Chapter IX. Criticism Of Mechanical Theories.In attempting to define our attitude to the mechanical theory of life, we have first of all to make sure that we have a right to take up a definite position at all. We should have less right, or perhaps none, if this theory of life were really of a purely“biological”nature, built up entirely from the expert knowledge and data which the biologist alone possesses. But the principles, assumptions, supplementary ideas and modes of expression along all the six lines we have discussed, the style and method according to which the hypothesis is constructed, the multitude of separate presuppositions with which it works, and indeed everything that helps to build up and knit the biological details into a scientific hypothesis, are the materials of rational synthesis in general, and as such are subject to general as well as to biological criticism. What is there, for instance, in Weismann's ingenious biophor-theory that can be called specifically biological, and not borrowed from other parts of the scientific system?One advantage, indeed, the biologist always has in this matter, apart from his special knowledge; that is,[pg 221]the technical instinct, the power of scenting out, so to speak, and immediately feeling the importance of the facts pertaining to his own discipline. It is this that gives every specialist the advantage over the layman in dealing with the data of his own subject. This power of instinctively appraising facts, which develops in the course of all special work, can, for instance in hypotheses in the domain of history, transform small details, which to the layman seem trivial, into weighty arguments. Similarly it may be that the success of the mechanical interpretation in regard to isolated processes may make its validity for many other allied processes certain, even though there is no precise proof of this. But we cannot regard this as a final demonstration of the applicability of the mechanical theory, since the same technical instinct in other experts leads them to reject the whole hypothesis.But here we are met with something surprising. May it not be that while we are impelled on general grounds to contend against the mechanical interpretation of vital phenomena, we are not so impelled onreligiousgrounds? May it not be that the instinct of the religious consciousness is misleading when it impels us—as probably every one will be able to certify from his own experience—to rebel against this mechanisation of life, the mechanical solution of its mysteries? Lotze, the energetic antagonist of“vital force,”the founder of the mechanical theory of vital processes, was himself a theist, and was so far from recognising any contradiction[pg 222]between the mechanical point of view and the Christian belief in God, that he included the former without ceremony in his theistic philosophical speculations. His view has become that of many theologians, and is often expressed in a definition of the boundaries between theology and natural science. According to the idea which was formulated by Lotze, and developed by others along his lines, the matter is quite simple. The interest which religion has in the processes of nature is at once and exclusively to be found in teleology. Are there purposes, plans, and ideas which govern and give meaning to the whole? The interest of natural science is purely in recognising inviolable causality; every phenomenon must have its compelling and sufficient reason in the system of causes preceding it. All that is and happens is absolutely determined by its causes, and nothing, nocausæ finalesfor instance, can co-operate with these causes in determining the result. But, as Lotze says, and as we have repeatedly pointed out, causal explanation does not exclude a consideration from the point of view of purpose, and the mechanical interpretation does not do so either. For this is nothing more than the causal explanation itself, only carried to complete consistency and definiteness. Purposes and ideas are not efficient causes but results. Where, for instance, there is a controlled purposive occurrence, the“purpose”nowhere appears as a factor co-operating with the series of causes, for these follow according to strict law, and the“purpose”reveals itself at the close[pg 223]of the series, as the result of a closed causal nexus, complete in itself, always provided that the initial links in the chain have been accurately estimated. The same is true of the processes of life. They are the ultimate result, strictly necessary and sufficiently accounted for in terms of mechanical sequence, of a long chain of causes whose initial links imply a definite constitution which could not be further reduced. Whether this ultimate result is merely a result or whether it is also a“purpose”is a question which, as we have seen twice already, it is wholly beyond the power of the causal mode of interpretation to answer. Given that an infinite intelligence in the world wished to realise purposes without instituting them as directly accomplished, but by letting them express themselves through a gradual“becoming,”the method would be exactly what is shown in the mechanical theory of life, that is, the primitive data and starting-points would have inherent in them a peculiar constitution and a rigidly inexorable orderliness of causal sequence. And Lotze emphasises that it would also be worthier of God to achieve the greatest by means of the simplest, and to work out the realisation of His eternal purposes according to the strict inevitableness of mechanism, than to attain His ends through the complicated means, the adventitious aids, and all the irregularities implied in the incommensurable activities of a“vital force.”(“God needs no minor gods.”)To Lotze himself these original data and starting[pg 224]points are the primitive forms of life, which, according to his view, are directly“given,”and cannot be referred back to anything else (except to“creation”). But it is obvious that his view can be enlarged and extended so as to refer the derivation of the whole animate world to the original raw materials of the cosmos (energy, matter, or whatsoever they may be), and to the orderly process by which these materials were combined in various configurations to form the chemical elements, the chemical compounds, living proteids, the first cell, and the whole series of higher forms. If this nexus has taken place, it is nothing else than the transformation of the“potential”into the“actual”through strict causality. And if this actuality proves itself to have claims, because of its own intrinsic worth, to be considered as intelligent“purpose,”the whole system of means, including the starting-point, can be recognised as the means to an end, and the original wisdom and the intelligence which ordained the purpose is only glorified the more through the great simplicity, the rational comprehensibility, and the inexorable necessity of the system, which excludes all chance, and therewith all possibility of error.This extension of Lotze's reconciliation of the mechanical causal with the teleological point of view is impressive and, as far as it goes, also quite convincing. It will never be given up, even if the point of view should change somewhat. And we have already seen that it is quite sufficient as long as we are dealing[pg 225]only with the question of teleology. But we must ask whether religion will be satisfied with“teleology”alone, or whether this is even the first requirement that it makes in regard to natural phenomena. We have already asked the question and attempted to clear the ground for an answer. Let us try to make it more definite.Many people will have a certain uneasiness in regard to the Lotzian ideas; they will be unable to rid themselves of a feeling that this way of looking at things is only apis allerfor the religious point of view, and that the fundamental requirements of religious feeling receive very inadequate satisfaction on this method. The world of life which has arisen thus is altogether too rational and transparent. It is calculable and mathematical. It satisfies well enough the need for teleology, and with that the need for a supreme, universally powerful and free intelligence; but it gives neither support nor nourishment to the essential element in religious feeling, through which alone faith becomes in the strict sense religious. Religion, even Christian religion, is, so to speak, a stratified structure, a graduated pyramid, expressing itself, at its second (and undoubtedly higher) level, in our recognition of purpose, the rationality of the world, our own spiritual and personal being and worth, but implying at its basis an inward sense of the mysterious, a joy in that which is incommensurable and unspeakable, which fills us with awe and devotion. And religion at the second[pg 226]stage must not sweep away the essence of the stage below, but must include it, at the same time informing it with new significance. Whoever does not possess his religion in this way will agree with, and will be quite satisfied with the Lotzian standpoint. But to any one who has experience of the most characteristic element in religion, it will be obvious that there must be a vague but deep-rooted antipathy between religion and the mathematical-mechanical conception of things. Evidence of the truth of this is to be found in the instinctive perceptions and valuations which mark even the naïve expressions of the religious consciousness.75For it is in full sympathy with a world which is riddled with what is inconceivable and incommensurable, in full sympathy with every evidence of the existence of such an element in the world of nature and mind, and therefore with every proof that the merely mechanical theory has its limits, that it does not suffice, and that its very insufficiency is a proof that the world is and remains in its depths mysterious. Now we have already said that the true sphere for such feeling is not the outer court[pg 227]of nature, but within the realm of the emotional life and of history, and, on the other hand, that even if the attempt to trace life back to the simpler forces of nature were successful, we should still be confronted with the riddle of the sphinx. But any one who would say frankly what he felt would at once be obliged to admit that the religious sense is very strongly stirred by the mystery of vital phenomena, and that in losing this he would lose a domain very dear to him. These sympathies and antipathies are in themselves sufficient to give an interest to the question of the insufficiency of the mechanical view of things.For it is by no means the case that the mechanical theory, with its premisses and principles, is the interpretation that best fits the facts, and that most naturally arises out of a calm consideration of the animate world. It is an artificial scheme, and astonishing energy has been expended on the attempt to fit it to the actual world, that it may make this orderly and translucent. It certainly yields this service so far, but not without often becoming a kind of strait-jacket, and revealing itself as an artificiality. In so far as the special problems of biology are concerned, we shall afterwards follow our previous method of taking our orientation from those specialists in the subject who, in reaction from the one-sidedness of the mechanical doctrine, have founded the“neo-vitalism”of to-day. Here we are only concerned with the generalities and presuppositions of the theory.[pg 228]We must dispute even the main justification of the theory, which is sought for in the old maxim of parsimony in the use of principles of explanation (entia, and alsoprincipia, præter necessitatem non esse multiplicanda), and in Kant's“regulative principle,”that science must proceed as if everything could ultimately be explained in terms of mechanism. For surely our task is to try to explain things, not at any cost with the fewest possible principles, but rather with the aid of those principles which appear most correct. If nature is not fundamentally simple, then it is not scientific but unscientific to simplify it theoretically. And the proposition bracketed above has its obvious converse side, that while entities and principles must not be multiplied except when it is necessary, on the other hand their number must not be arbitrarily lessened. To proceed according to the fundamental maxims of the mechanistic view can only be wholesome for a time and, so to speak, for pædagogical reasons. To apply them seriously and permanently would be highly injurious, for, by prejudging what is discoverable in nature, it would tend to prevent the calm, objective study of things which asks for nothing more than to see them as they are. It would thus destroy the fineness of our appreciation of what there really is in nature. This is true alike of forcible attempts to reduce the processes of life to mechanical processes, and of the Darwinian doctrine of the universal dominance of utility. Both bear unmistakably the stamp of foregone conclusions, and betray[pg 229]a desire for the simplest, rather than for the most correct principles of interpretation.There is one point which presses itself on the notice even of outsiders, and is probably realised even more keenly by specialists. The confidence of the supporters of the mechanical theories of earlier days, from Descartes onward, that animals and the bodies of men were machines, mechanical automata, down to the mechanical theories of Lamettrie and Holbach, ofl'homme machine, and of thesystème de la nature, was at least as great as, probably greater than, that of the supporters of the modern theories. Yet how naïve and presumptuous seem the crude and wooden theories upon which the mechanical system was formerly built up, and how falsely interpreted seem the physiological and other facts which lent them support, when seen in the light of our modern physiological knowledge. Vaucanson's or Drozsch's duck-automaton or clockwork-man, with which the mechanical theorists of bygone days amused themselves, would not go far to encourage the physiologist of to-day to pursue his mechanical studies, but would rather throw a vivid light on the impossibility of comparing the living“machine”with machines in the usual sense. For things emphatically do not happen within the living organism in the same way as in the automatic duck, and the more exact the resemblance to the functions of a“real”duck became, the more did the system of means by which the end was attained become unlike vital processes. It is difficult to resist the[pg 230]impression that in another hundred years,—perhaps again from the standpoint of new and definitely accepted mechanical explanations,—people will regard our developmental mechanics, cellular mechanics, and other vital mechanics much in the same way as we now look on Vaucanson's duck.Associated or even identical with this is the fact that in proportion as mechanical interpretation advances, the difficulties it has to surmount continually crop up anew. Processes which seem of the simplest kind and the most likely to be capable of purely mechanical explanation, processes such as those of assimilation, digestion, respiration, for which it was believed that exact parallels existed in the purely mechanical domain, as, for instance, in the osmotic processes of porous membranes, are seen when closely scrutinised as they occur in the living body to be extremely complex; in fact they have to be transferred“provisionally”from the mechanical to the vital rubric. To this category belong the whole modern development of the cell-theory, which replaces the previouslysinglemechanism in the living body by millions of them, every one of which raises as many problems as the one had done in the days of cruder interpretation. Every individual cell, as it appears to our understanding to-day, is at least as complicated a riddle as the whole organism formerly appeared.But further: the modern development of biology has emphasised a special problem, which was first formulated[pg 231]by Leibnitz (though it is in antithesis to his fundamental Monad-theory), and which appears incapable of solution on mechanical lines. Leibnitz declared living beings to be“machines,”but machines of a peculiar kind. Even the most complicated machine, in the ordinary sense, consists of a combination of smaller“machines,”that is to say, of wheels, systems of levers, &c., of a simpler kind. And these sub-machines may in their turn consist of still simpler ones, and so on. But ultimately a stage is reached when the component parts are homogeneous, and cannot be analysed into simpler machines. It is otherwise with the organism. According to Leibnitz it consists of machines made up of other machines, and so on, into the infinitely little. However far we can proceed in our analysis of the parts, we shall still find that they are syntheses, made up of most ingeniously complex component parts, and this as far as our powers of seeing and distinguishing will carry us. That is to say: organisation is continued on into the infinitely little.Leibnitz's illustration of the fish-pond is well known. He could have no better corroboration of his theory than the results of modern investigation afford. His doctrine of the continuation of organisation downwards into ever smaller expression is confirmed to a certain extent even by anatomy. By analysing structural organisation down to cells a definite point seemed to have been reached. But it now appears that at that point the problem is only beginning. One organisation is made[pg 232]up of other organisations—cells, protoplasm, nucleus, nucleolus, centrosomes, and so on, according to the power of the microscope; and these structures, instead of explaining the vital functions of growth, development, multiplication by division, and the rest, simply repeat them on a smaller scale, and are thus in their turn living units, the aggregation of which is illustrated better by the analogy of a social organism than by that of a mechanical structure.In order to follow the mechanical explanation along the six lines we have previously indicated, we shall, as we have already said, entrust ourselves to the specialists who are on the opposite side. The difficulties and objections which the mechanical theory has to face have forced themselves insistently upon us even in the course of a short sketch such as has just been given, but they will be clearly realised if we approach them from the other side. But, first of all, a word as to the fundamental and, it is alleged, unassailable doctrine on which the theory as a whole is based, the“law of the conservation of energy.”The appeal to this, at any rate in the way in which it is usually made, is apt to be so distorted that the case must first be clearly stated before we can get further with the discussion.The Law of the Conservation of Energy.Helmholtz's proof established mathematically what Kant had already, by direct insight, advanced as anà priorifundamental axiom: that in any given system[pg 233]the sum of energy can neither increase (impossibility of aperpetuum mobile) nor diminish (there is no disappearance of energy, but only transformation into another form). But even the vitalist had no need to deny this proposition. The“energy”which is required for the work of directing, setting agoing, changing and rearranging the chemico-physical processes in the body, and bringing about the effective reactions to stimuli which result in“development,”“transmission,”“regeneration,”and so on—if indeed any energy is required—of course could not come“from within”as a spontaneous increase of the existing sum of energy—that would, indeed, be a magical becoming out of nothing!—but must naturally be thought of as coming“from without.”The appeal to the law of the conservation of energy is therefore in itself irrelevant; but it conceals behind it an assertion of a totally different kind, namely, that in relation to physico-chemical sequences there can be no“without,”nothing transcending them—an assertion which Helmholtz's arguments cannot and were never intended to establish. But before any definite attitude to this newly imported assertion could be taken up, it would require to be distinctly defined, and that would lead us at once into all the depths of epistemological discussion. Here, therefore, we can only say so much: If this assertion is accepted it is well to see where it carries us; namely, back to the first-described naïve standpoint, which, without critical scruples, quite seriously accepts the world as it appears to it for the[pg 234]reality, and quite seriously speaks of an infinity lying in time behind us—and therefore come to an end—and is not in the least disturbed from its“dogmatic slumber”by this or any of the other great antinomies of our conception of the universe. And it remains, too, for this standpoint to come to terms with the fact that, in voluntary actions, of which we have the most direct knowledge, we have through our will the power of intervention in the physico-chemical nexus of our bodily energies—a fact which implies the existence of a“without,”from which interpolations or influences may flow into the physico-chemical system, even if there be none in regard to the domain of“vital”phenomena. And we should require to find out through what parallelistic or abruptly idealistic system the“without”was done away with in this case. For if a transcendental basis, or reverse side, or cause of things, be admitted—even if only in the form of our materialistic popular metaphysics (the“substance”of Haeckel's“world-riddle”)—then a“without,”from which primarily the cosmic system with its constant sum of matter and energy is explained, is also admitted, and it is difficult to see why it should have exhausted itself in this single effort.Criticisms of the Mechanistic Theory of Life.The course of the mechanistic theory of life has been surprisingly similar to that of its complement, the theory of the general evolution of the organic world.[pg 235]The two great doctrines of the schools, Darwinism on the one hand, the mechanical interpretation of life on the other, are both tottering, not because of the criticism of outsiders, but of specialists within the schools themselves. And the interest which religion has in this is the same in both cases: the transcendental nature of things, the mysterious depth of appearance, which these theories denied or obscured, become again apparent. The incommensurableness and mystery of the world, which are, perhaps, even more necessary to the very life of religion than the right to regard it teleologically, reassert themselves afresh in the all-too-comprehensible and mathematically-formulated world, and re-establish themselves, notwithstanding obstinate and persistent attempts to do away with them. This is perhaps to the advantage of both natural science and religion: to the advantage of religion because it can with difficulty co-exist with the universal dominance of the mathematical way of looking at things; to the advantage of natural science because, in giving up the one-sidedness of the purely quantitative outlook, it does not give up its“foundations,”its“right to exist,”but only apetitio principiiand a prejudice that compelled it to exploit nature rather than to explain it, and to prescribe its ways rather than to seek them out.The reaction from the one-sided mechanical theories shows itself in many different ways and degrees. It may, according to the individual naturalist, affect the[pg 236]theory as a whole, or only certain parts of it, or only particular lines. It starts with mere criticism and with objections, which go no further than saying that“in the meantime”we are still far from having reached a physico-chemical solution of the riddle of life; it may ascend through all stages up to an absolute rejection of the theory as an idiosyncrasy of the time which impedes the progress of investigation, and as an uncritical prejudice of the schools. It may remain at the level of mere protest, and content itself with demonstrating the insufficiency of the mechanical explanation, without attempting to formulate any independent theory for the domain of the vital; or it may construct a specifically biological theory, claiming independence amid other disciplines, and basing this claim on the autonomy of vital processes; or it may widen out deliberately into metaphysical study and speculation. Taken at all these levels it presents such a complete section of the trend of modern ideas and problems that it would be an attractive study even apart from the special interest which attaches to it from the point of view of religious and idealistic conceptions of the universe.Both Liebig and Johannes Müller remained vitalists, notwithstanding the discovery of the synthesis of urea and the increasing number of organic compounds which were built up artificially by purely chemical methods. It was only about the middle of the last century that the younger generation, under the leadership, in Germany, of Du Bois-Reymond in particular, went over[pg 237]decidedly to the mechanistic side, and carried the doctrines of the school to ever fresh victories. But opposition was not lacking from the outset, though it was restrained and cautious.Virchow's“Caution”.Here, as also in regard to“Darwinism,”which was advanced about the same time, the typical advocate of“caution”was Rudolf Virchow. His doubts and reservations found utterance very soon after the theory itself had been promulgated. In his“Cellular Pathologie,”76and in an essay on“The Old Vitalism and the New,”77he puts in a word for avis vitalis. The old vitalism, he declared, had been false because it assumed, not avis, but aspiritus vitalis. The substances in animate and in inanimate bodies have undoubtedly absolutely the same properties. Nevertheless,“we must at once rid ourselves of the scientific prudery of regarding the processes of life solely as the mechanical result of the molecular forces inherent in their constituent bodily parts.”The essential feature of life is a derived and communicated forceadditionalto the molecular forces. Whence it comes we are not told. He glided all round the problem with platitudinarian expressions, which were intended to show his own adherence as a matter of course to the new biological school, and which revealed at the same time his striking incapacity for defining a[pg 238]problem with any precision. At a“certain period in the evolution of the earth”this force arose, as the ordinary mechanical movements“swung over”into the vital. But it is thus a special form of movement, which detaches itself from the great constants of general movement, and runs its course alongside of, and in constant relation to, these. (Did ever vitalist assert more?) After thus preparing the way for a return of the veering process at a particular stage of evolution, and giving the necessary assurances against the“diametrically opposed dualistic position,”Virchow employs almost all the arguments against the mechanical theory which vitalists have ever brought forward. Even the catalytic properties of ferments are above the“ordinary”physical and chemical forces. The movement of crystallisation, too, cannot be compared with the vital movement. For vital force is not immanent in matter, but is always the product of previous life.78In the simplest processes of growth and nutrition thevis vitalisplays its vitalrôle. This is true in a much greater degree of the processes of development and morphogenesis. In the phenomena of irritability life reveals its spontaneity through“responses,”and so on.“Peu d'anatomie pathologique éloigne du vitalisme, beaucoup d'anatomie pathologique y ramène.”It is impossible to make much of this position. It leaves the theory with one of the opposing parties, the[pg 239]practice with the other, and the problem just where it was before.Preyer's Position.Along with Virchow, we must name another of the older generation, the physiologist William Preyer, who combated“vitalism,”“dualism,”and“mechanism”with equal vehemence, and issued a manifesto, already somewhat solemn and official, against“vital force.”And yet he must undoubtedly be regarded as a vitalist by mechanists and vitalists alike.79He is more definite than Virchow, for he does not content himself with general statements as to the“origin”of vital force, and of the“swinging over”of the merely mechanical energies into the domain of the vital, but holds decidedly to the propositionomne vivum e vivo. He therefore maintains that life has always existed in the cosmos, and entirely rejects spontaneous generation.The fallacy, he says, of the mechanistic claims was due to the increasing number of physical explanations of isolated vital phenomena, and of imitations of the chemical products of organic metabolism. A wrong conclusion was drawn from these.“Any one who hopes to deduce from the chemical and physical properties of the fertilised egg the necessity that an animal, tormented by hunger and love must, after a[pg 240]certain time, arise therefrom, has a pathetic resemblance to the miserable manufacturers of homunculi.”Life is one of the underivable and inexplicable fundamental functions of universal being. From all eternity life has only been produced from life.As Preyer accepts the Kant-Laplace theory of the origin of our earth from the sun, he reaches ideas which have points of contact with the“cosmo-organic”ideas of Fechner. Life was present even when the earth was a fiery fluid sphere, and was possibly more general and more abundant then than it is now. And life as we know it may only be a smaller and isolated expression of that more general life.80[pg 241]Among the younger generation of specialists, those most often quoted as opponents of the mechanical theory are probably Bunge, Rindfleisch, Kerner von Marilaun, Neumeister and Wolff. A special group among them, not very easy to classify, may be called the Tectonists. Associated with them is Reinke's“Theory of Dominants.”Driesch started from their ranks, and is a most interesting example of consistent development from a recognition of the impossibilities of the mechanistic position to an individually thought-out vitalistic theory. Hertwig, too, takes a very definite position of his own in regard to these matters. Perhaps the most original contribution in the whole field is Albrecht's“Theory of Different Modes of Regarding Things.”We may close the list with the name of K. C. Schneider, who has carried these modern ideas on into metaphysical speculation. Several others might be mentioned along with and connecting these representative names.81[pg 242]The Position Of Bunge and Other Physiologists.For a long time one of the most prominent figures in the controversy was Prof. G. Bunge, of Basle, who was one of the first modern physiologists to champion vitalism, and who has tried to show by analogies and illustrations what is necessarily implied in vital activity.82The mechanical reduction of vital phenomena to physico-chemical forces, he says, is impossible, and becomes more and more so as our knowledge deepens. He brings forward a series of convincing examples of the way in which apparent mechanical explanations have broken down. The absorption of the chyle through the walls of the intestine seemed to be a mechanically intelligible process[pg 243]of osmosis and diffusion. But in reality it proves to be rather a process of selection on the part of the epithelial cells of the intestine, analogous to the selection and rejection exercised elsewhere by unicellular organisms. In the same way the epithelial cells of the mammary glands“select”the suitable substances from the blood. It is impossible to explain in a mechanical way the power which directs the innumerable different chemical and physical processes within the organism, whether they be the bewilderingly purposeful reactions in the individual life of the cell, which seem to point to psychic processes within the plasm, or the riddles of development and of inheritance in particular; for how can a spermatozoon, so small that 500 millions can lie on a cubic line, be the bearer of all the peculiarities of the father to the son?In Lecture III. Bunge defines his attitude towards the law of the conservation of energy. In so doing he unconsciously follows the lines laid down by Descartes. All processes of movement and all functions exhibited by the living substance are the results of the accumulated potential energies, and the sums of work done and energy utilised remain the same. But the liberation and the direction of these energies is a factor by itself, which neither increases nor diminishes the sum of energies.“Occasiones”and“causæ”are brought into the field once more. The energies effect the phenomena, but they require“occasiones”to liberate them—thus a stone may fall to the ground by virtue of the[pg 244]potential energies stored in it at the time of its suspension, but it cannot fall until the thread by which it hangs has been cut. The function of the“occasio”itself is something quite outside of and without relation to the effect caused; it is a matter of indifference whether the thread be cut gently through with a razor or shot in two with a cannon ball.Kassowitz83is an instructive example of how much the force of criticism has been recognised even by those occupying a convinced mechanical point of view. He subjects all the different theories which attempt to explain the chief vital phenomena in mechanical terms to a long and exhaustive examination. The theories of the organism as a thermodynamic engine, osmotic theories, theories of ferments, interpretations in terms of electro-dynamics and molecular-physics—are all examined (chap. iv.); and the failure of all these hypotheses, notwithstanding the enormous amount of ingenuity expended in their construction, is summed up in an emphatic“Ignoramus.”“The failure is a striking one,”and it is frankly admitted that, in strong contrast to the earlier mood of confident hope, there now prevails a mood of resignation in regard to the mechanical-experimental investigation of the living organism, and that even specialists of the first rank are finding that they have to reckon again seriously with vital force. This breakdown and these admissions do not exactly tend to prejudice us in favour of the[pg 245]author's own attempt to substantiate new mechanical theories.In the comprehensive text-book of physiological chemistry by R. Neumeister, the mechanical standpoint seemed to be adhered to as the ideal. But the same writer forsakes it entirely, and disputes it energetically in his most recent work,“Betrachtungen über das Wesen der Lebenserscheinungen”84(“Considerations as to the Nature of Vital Phenomena”). He passes over all the larger problems, such as those of development, inheritance, regeneration, and confines himself in the main to the physiological functions of protoplasm, especially to those of the absorption of food and metabolism. And he shows, by means of illustrations, in part Bunge's, in part his own, and in close sympathy with Wundt's views, that even these vital phenomena cannot possibly be explained in terms of chemical affinity, physical osmosis, and the like. In processes of selection (such as, for instance, the excretion of urea and the retention of sugar in the blood), the“aim is obvious, but the causes cannot be recognised.”Psychical processes play a certain part in the functions of protoplasm in the form of qualitative and quantitative sensitiveness. All the mechanical processes in living organisms are initiated and directed by psychical processes. Physical, chemical and mechanical laws are perfectly valid, but they are not absolutely dominant. Living matter is to be defined as“a unique chemical[pg 246]system, the molecules of which, by their peculiar reciprocal action, give rise to psychical and material processes in such a way that the processes of the one kind are always causally conditioned and started by those of the other kind.”The psychical phenomena he regards as transcendental, supernatural,“mystical,”yet unquestionably also subject to a strict causal nexus, although the causality must remain for ever concealed. Starting from this basis, he analyses and rejects the explanations which have been offered in terms of the analogy of ferments, enzymes, or catalytic processes. In particular, he disputes Ostwald's“Energismus”and Verworn's Biogen hypothesis.85[pg 247]Among the vitalists of to-day, one of the most frequently cited, perhaps, except Driesch the most frequently cited, is G. Wolff, aPrivatdozent, formerly at Würzburg, now at Basle. He has only published short lectures and essays, and these deal not so much with the mechanical theory as with Darwinism.86But in these writings his main argument is that of his concluding chapter: the spontaneous adaptiveness of the organism, which nullifies all contingent theories to explain the purposiveness in ontogeny and phylogeny. And in his lecture,“Mechanismus und Vitalismus,”87in which he directs his attention especially to criticising Bütschli's defence of mechanism, the only problem to which prominence is given is the one with which we are here concerned. In spite of their brevity, these writings have given rise to much controversy, because what is peculiar to the two standpoints is described with precision, and the problem is clearly defined. His criticism had its starting-point in, and received a special impulse from an empirical proof, due to a very happy experiment of his own, of the marvellous regenerative capacity, and the inherent purposive[pg 248]activity of the living organism. He succeeded in proving that if the lens of the eye of the newt be excised, it may be regrown. The importance of this fact is greatly increased if we trace out in detail the various impossible rival mechanical interpretations which have grown up around this interesting case. As Driesch says,“It is not a restoration starting from the wound, it is a substitution starting from a different place.”
Chapter IX. Criticism Of Mechanical Theories.In attempting to define our attitude to the mechanical theory of life, we have first of all to make sure that we have a right to take up a definite position at all. We should have less right, or perhaps none, if this theory of life were really of a purely“biological”nature, built up entirely from the expert knowledge and data which the biologist alone possesses. But the principles, assumptions, supplementary ideas and modes of expression along all the six lines we have discussed, the style and method according to which the hypothesis is constructed, the multitude of separate presuppositions with which it works, and indeed everything that helps to build up and knit the biological details into a scientific hypothesis, are the materials of rational synthesis in general, and as such are subject to general as well as to biological criticism. What is there, for instance, in Weismann's ingenious biophor-theory that can be called specifically biological, and not borrowed from other parts of the scientific system?One advantage, indeed, the biologist always has in this matter, apart from his special knowledge; that is,[pg 221]the technical instinct, the power of scenting out, so to speak, and immediately feeling the importance of the facts pertaining to his own discipline. It is this that gives every specialist the advantage over the layman in dealing with the data of his own subject. This power of instinctively appraising facts, which develops in the course of all special work, can, for instance in hypotheses in the domain of history, transform small details, which to the layman seem trivial, into weighty arguments. Similarly it may be that the success of the mechanical interpretation in regard to isolated processes may make its validity for many other allied processes certain, even though there is no precise proof of this. But we cannot regard this as a final demonstration of the applicability of the mechanical theory, since the same technical instinct in other experts leads them to reject the whole hypothesis.But here we are met with something surprising. May it not be that while we are impelled on general grounds to contend against the mechanical interpretation of vital phenomena, we are not so impelled onreligiousgrounds? May it not be that the instinct of the religious consciousness is misleading when it impels us—as probably every one will be able to certify from his own experience—to rebel against this mechanisation of life, the mechanical solution of its mysteries? Lotze, the energetic antagonist of“vital force,”the founder of the mechanical theory of vital processes, was himself a theist, and was so far from recognising any contradiction[pg 222]between the mechanical point of view and the Christian belief in God, that he included the former without ceremony in his theistic philosophical speculations. His view has become that of many theologians, and is often expressed in a definition of the boundaries between theology and natural science. According to the idea which was formulated by Lotze, and developed by others along his lines, the matter is quite simple. The interest which religion has in the processes of nature is at once and exclusively to be found in teleology. Are there purposes, plans, and ideas which govern and give meaning to the whole? The interest of natural science is purely in recognising inviolable causality; every phenomenon must have its compelling and sufficient reason in the system of causes preceding it. All that is and happens is absolutely determined by its causes, and nothing, nocausæ finalesfor instance, can co-operate with these causes in determining the result. But, as Lotze says, and as we have repeatedly pointed out, causal explanation does not exclude a consideration from the point of view of purpose, and the mechanical interpretation does not do so either. For this is nothing more than the causal explanation itself, only carried to complete consistency and definiteness. Purposes and ideas are not efficient causes but results. Where, for instance, there is a controlled purposive occurrence, the“purpose”nowhere appears as a factor co-operating with the series of causes, for these follow according to strict law, and the“purpose”reveals itself at the close[pg 223]of the series, as the result of a closed causal nexus, complete in itself, always provided that the initial links in the chain have been accurately estimated. The same is true of the processes of life. They are the ultimate result, strictly necessary and sufficiently accounted for in terms of mechanical sequence, of a long chain of causes whose initial links imply a definite constitution which could not be further reduced. Whether this ultimate result is merely a result or whether it is also a“purpose”is a question which, as we have seen twice already, it is wholly beyond the power of the causal mode of interpretation to answer. Given that an infinite intelligence in the world wished to realise purposes without instituting them as directly accomplished, but by letting them express themselves through a gradual“becoming,”the method would be exactly what is shown in the mechanical theory of life, that is, the primitive data and starting-points would have inherent in them a peculiar constitution and a rigidly inexorable orderliness of causal sequence. And Lotze emphasises that it would also be worthier of God to achieve the greatest by means of the simplest, and to work out the realisation of His eternal purposes according to the strict inevitableness of mechanism, than to attain His ends through the complicated means, the adventitious aids, and all the irregularities implied in the incommensurable activities of a“vital force.”(“God needs no minor gods.”)To Lotze himself these original data and starting[pg 224]points are the primitive forms of life, which, according to his view, are directly“given,”and cannot be referred back to anything else (except to“creation”). But it is obvious that his view can be enlarged and extended so as to refer the derivation of the whole animate world to the original raw materials of the cosmos (energy, matter, or whatsoever they may be), and to the orderly process by which these materials were combined in various configurations to form the chemical elements, the chemical compounds, living proteids, the first cell, and the whole series of higher forms. If this nexus has taken place, it is nothing else than the transformation of the“potential”into the“actual”through strict causality. And if this actuality proves itself to have claims, because of its own intrinsic worth, to be considered as intelligent“purpose,”the whole system of means, including the starting-point, can be recognised as the means to an end, and the original wisdom and the intelligence which ordained the purpose is only glorified the more through the great simplicity, the rational comprehensibility, and the inexorable necessity of the system, which excludes all chance, and therewith all possibility of error.This extension of Lotze's reconciliation of the mechanical causal with the teleological point of view is impressive and, as far as it goes, also quite convincing. It will never be given up, even if the point of view should change somewhat. And we have already seen that it is quite sufficient as long as we are dealing[pg 225]only with the question of teleology. But we must ask whether religion will be satisfied with“teleology”alone, or whether this is even the first requirement that it makes in regard to natural phenomena. We have already asked the question and attempted to clear the ground for an answer. Let us try to make it more definite.Many people will have a certain uneasiness in regard to the Lotzian ideas; they will be unable to rid themselves of a feeling that this way of looking at things is only apis allerfor the religious point of view, and that the fundamental requirements of religious feeling receive very inadequate satisfaction on this method. The world of life which has arisen thus is altogether too rational and transparent. It is calculable and mathematical. It satisfies well enough the need for teleology, and with that the need for a supreme, universally powerful and free intelligence; but it gives neither support nor nourishment to the essential element in religious feeling, through which alone faith becomes in the strict sense religious. Religion, even Christian religion, is, so to speak, a stratified structure, a graduated pyramid, expressing itself, at its second (and undoubtedly higher) level, in our recognition of purpose, the rationality of the world, our own spiritual and personal being and worth, but implying at its basis an inward sense of the mysterious, a joy in that which is incommensurable and unspeakable, which fills us with awe and devotion. And religion at the second[pg 226]stage must not sweep away the essence of the stage below, but must include it, at the same time informing it with new significance. Whoever does not possess his religion in this way will agree with, and will be quite satisfied with the Lotzian standpoint. But to any one who has experience of the most characteristic element in religion, it will be obvious that there must be a vague but deep-rooted antipathy between religion and the mathematical-mechanical conception of things. Evidence of the truth of this is to be found in the instinctive perceptions and valuations which mark even the naïve expressions of the religious consciousness.75For it is in full sympathy with a world which is riddled with what is inconceivable and incommensurable, in full sympathy with every evidence of the existence of such an element in the world of nature and mind, and therefore with every proof that the merely mechanical theory has its limits, that it does not suffice, and that its very insufficiency is a proof that the world is and remains in its depths mysterious. Now we have already said that the true sphere for such feeling is not the outer court[pg 227]of nature, but within the realm of the emotional life and of history, and, on the other hand, that even if the attempt to trace life back to the simpler forces of nature were successful, we should still be confronted with the riddle of the sphinx. But any one who would say frankly what he felt would at once be obliged to admit that the religious sense is very strongly stirred by the mystery of vital phenomena, and that in losing this he would lose a domain very dear to him. These sympathies and antipathies are in themselves sufficient to give an interest to the question of the insufficiency of the mechanical view of things.For it is by no means the case that the mechanical theory, with its premisses and principles, is the interpretation that best fits the facts, and that most naturally arises out of a calm consideration of the animate world. It is an artificial scheme, and astonishing energy has been expended on the attempt to fit it to the actual world, that it may make this orderly and translucent. It certainly yields this service so far, but not without often becoming a kind of strait-jacket, and revealing itself as an artificiality. In so far as the special problems of biology are concerned, we shall afterwards follow our previous method of taking our orientation from those specialists in the subject who, in reaction from the one-sidedness of the mechanical doctrine, have founded the“neo-vitalism”of to-day. Here we are only concerned with the generalities and presuppositions of the theory.[pg 228]We must dispute even the main justification of the theory, which is sought for in the old maxim of parsimony in the use of principles of explanation (entia, and alsoprincipia, præter necessitatem non esse multiplicanda), and in Kant's“regulative principle,”that science must proceed as if everything could ultimately be explained in terms of mechanism. For surely our task is to try to explain things, not at any cost with the fewest possible principles, but rather with the aid of those principles which appear most correct. If nature is not fundamentally simple, then it is not scientific but unscientific to simplify it theoretically. And the proposition bracketed above has its obvious converse side, that while entities and principles must not be multiplied except when it is necessary, on the other hand their number must not be arbitrarily lessened. To proceed according to the fundamental maxims of the mechanistic view can only be wholesome for a time and, so to speak, for pædagogical reasons. To apply them seriously and permanently would be highly injurious, for, by prejudging what is discoverable in nature, it would tend to prevent the calm, objective study of things which asks for nothing more than to see them as they are. It would thus destroy the fineness of our appreciation of what there really is in nature. This is true alike of forcible attempts to reduce the processes of life to mechanical processes, and of the Darwinian doctrine of the universal dominance of utility. Both bear unmistakably the stamp of foregone conclusions, and betray[pg 229]a desire for the simplest, rather than for the most correct principles of interpretation.There is one point which presses itself on the notice even of outsiders, and is probably realised even more keenly by specialists. The confidence of the supporters of the mechanical theories of earlier days, from Descartes onward, that animals and the bodies of men were machines, mechanical automata, down to the mechanical theories of Lamettrie and Holbach, ofl'homme machine, and of thesystème de la nature, was at least as great as, probably greater than, that of the supporters of the modern theories. Yet how naïve and presumptuous seem the crude and wooden theories upon which the mechanical system was formerly built up, and how falsely interpreted seem the physiological and other facts which lent them support, when seen in the light of our modern physiological knowledge. Vaucanson's or Drozsch's duck-automaton or clockwork-man, with which the mechanical theorists of bygone days amused themselves, would not go far to encourage the physiologist of to-day to pursue his mechanical studies, but would rather throw a vivid light on the impossibility of comparing the living“machine”with machines in the usual sense. For things emphatically do not happen within the living organism in the same way as in the automatic duck, and the more exact the resemblance to the functions of a“real”duck became, the more did the system of means by which the end was attained become unlike vital processes. It is difficult to resist the[pg 230]impression that in another hundred years,—perhaps again from the standpoint of new and definitely accepted mechanical explanations,—people will regard our developmental mechanics, cellular mechanics, and other vital mechanics much in the same way as we now look on Vaucanson's duck.Associated or even identical with this is the fact that in proportion as mechanical interpretation advances, the difficulties it has to surmount continually crop up anew. Processes which seem of the simplest kind and the most likely to be capable of purely mechanical explanation, processes such as those of assimilation, digestion, respiration, for which it was believed that exact parallels existed in the purely mechanical domain, as, for instance, in the osmotic processes of porous membranes, are seen when closely scrutinised as they occur in the living body to be extremely complex; in fact they have to be transferred“provisionally”from the mechanical to the vital rubric. To this category belong the whole modern development of the cell-theory, which replaces the previouslysinglemechanism in the living body by millions of them, every one of which raises as many problems as the one had done in the days of cruder interpretation. Every individual cell, as it appears to our understanding to-day, is at least as complicated a riddle as the whole organism formerly appeared.But further: the modern development of biology has emphasised a special problem, which was first formulated[pg 231]by Leibnitz (though it is in antithesis to his fundamental Monad-theory), and which appears incapable of solution on mechanical lines. Leibnitz declared living beings to be“machines,”but machines of a peculiar kind. Even the most complicated machine, in the ordinary sense, consists of a combination of smaller“machines,”that is to say, of wheels, systems of levers, &c., of a simpler kind. And these sub-machines may in their turn consist of still simpler ones, and so on. But ultimately a stage is reached when the component parts are homogeneous, and cannot be analysed into simpler machines. It is otherwise with the organism. According to Leibnitz it consists of machines made up of other machines, and so on, into the infinitely little. However far we can proceed in our analysis of the parts, we shall still find that they are syntheses, made up of most ingeniously complex component parts, and this as far as our powers of seeing and distinguishing will carry us. That is to say: organisation is continued on into the infinitely little.Leibnitz's illustration of the fish-pond is well known. He could have no better corroboration of his theory than the results of modern investigation afford. His doctrine of the continuation of organisation downwards into ever smaller expression is confirmed to a certain extent even by anatomy. By analysing structural organisation down to cells a definite point seemed to have been reached. But it now appears that at that point the problem is only beginning. One organisation is made[pg 232]up of other organisations—cells, protoplasm, nucleus, nucleolus, centrosomes, and so on, according to the power of the microscope; and these structures, instead of explaining the vital functions of growth, development, multiplication by division, and the rest, simply repeat them on a smaller scale, and are thus in their turn living units, the aggregation of which is illustrated better by the analogy of a social organism than by that of a mechanical structure.In order to follow the mechanical explanation along the six lines we have previously indicated, we shall, as we have already said, entrust ourselves to the specialists who are on the opposite side. The difficulties and objections which the mechanical theory has to face have forced themselves insistently upon us even in the course of a short sketch such as has just been given, but they will be clearly realised if we approach them from the other side. But, first of all, a word as to the fundamental and, it is alleged, unassailable doctrine on which the theory as a whole is based, the“law of the conservation of energy.”The appeal to this, at any rate in the way in which it is usually made, is apt to be so distorted that the case must first be clearly stated before we can get further with the discussion.The Law of the Conservation of Energy.Helmholtz's proof established mathematically what Kant had already, by direct insight, advanced as anà priorifundamental axiom: that in any given system[pg 233]the sum of energy can neither increase (impossibility of aperpetuum mobile) nor diminish (there is no disappearance of energy, but only transformation into another form). But even the vitalist had no need to deny this proposition. The“energy”which is required for the work of directing, setting agoing, changing and rearranging the chemico-physical processes in the body, and bringing about the effective reactions to stimuli which result in“development,”“transmission,”“regeneration,”and so on—if indeed any energy is required—of course could not come“from within”as a spontaneous increase of the existing sum of energy—that would, indeed, be a magical becoming out of nothing!—but must naturally be thought of as coming“from without.”The appeal to the law of the conservation of energy is therefore in itself irrelevant; but it conceals behind it an assertion of a totally different kind, namely, that in relation to physico-chemical sequences there can be no“without,”nothing transcending them—an assertion which Helmholtz's arguments cannot and were never intended to establish. But before any definite attitude to this newly imported assertion could be taken up, it would require to be distinctly defined, and that would lead us at once into all the depths of epistemological discussion. Here, therefore, we can only say so much: If this assertion is accepted it is well to see where it carries us; namely, back to the first-described naïve standpoint, which, without critical scruples, quite seriously accepts the world as it appears to it for the[pg 234]reality, and quite seriously speaks of an infinity lying in time behind us—and therefore come to an end—and is not in the least disturbed from its“dogmatic slumber”by this or any of the other great antinomies of our conception of the universe. And it remains, too, for this standpoint to come to terms with the fact that, in voluntary actions, of which we have the most direct knowledge, we have through our will the power of intervention in the physico-chemical nexus of our bodily energies—a fact which implies the existence of a“without,”from which interpolations or influences may flow into the physico-chemical system, even if there be none in regard to the domain of“vital”phenomena. And we should require to find out through what parallelistic or abruptly idealistic system the“without”was done away with in this case. For if a transcendental basis, or reverse side, or cause of things, be admitted—even if only in the form of our materialistic popular metaphysics (the“substance”of Haeckel's“world-riddle”)—then a“without,”from which primarily the cosmic system with its constant sum of matter and energy is explained, is also admitted, and it is difficult to see why it should have exhausted itself in this single effort.Criticisms of the Mechanistic Theory of Life.The course of the mechanistic theory of life has been surprisingly similar to that of its complement, the theory of the general evolution of the organic world.[pg 235]The two great doctrines of the schools, Darwinism on the one hand, the mechanical interpretation of life on the other, are both tottering, not because of the criticism of outsiders, but of specialists within the schools themselves. And the interest which religion has in this is the same in both cases: the transcendental nature of things, the mysterious depth of appearance, which these theories denied or obscured, become again apparent. The incommensurableness and mystery of the world, which are, perhaps, even more necessary to the very life of religion than the right to regard it teleologically, reassert themselves afresh in the all-too-comprehensible and mathematically-formulated world, and re-establish themselves, notwithstanding obstinate and persistent attempts to do away with them. This is perhaps to the advantage of both natural science and religion: to the advantage of religion because it can with difficulty co-exist with the universal dominance of the mathematical way of looking at things; to the advantage of natural science because, in giving up the one-sidedness of the purely quantitative outlook, it does not give up its“foundations,”its“right to exist,”but only apetitio principiiand a prejudice that compelled it to exploit nature rather than to explain it, and to prescribe its ways rather than to seek them out.The reaction from the one-sided mechanical theories shows itself in many different ways and degrees. It may, according to the individual naturalist, affect the[pg 236]theory as a whole, or only certain parts of it, or only particular lines. It starts with mere criticism and with objections, which go no further than saying that“in the meantime”we are still far from having reached a physico-chemical solution of the riddle of life; it may ascend through all stages up to an absolute rejection of the theory as an idiosyncrasy of the time which impedes the progress of investigation, and as an uncritical prejudice of the schools. It may remain at the level of mere protest, and content itself with demonstrating the insufficiency of the mechanical explanation, without attempting to formulate any independent theory for the domain of the vital; or it may construct a specifically biological theory, claiming independence amid other disciplines, and basing this claim on the autonomy of vital processes; or it may widen out deliberately into metaphysical study and speculation. Taken at all these levels it presents such a complete section of the trend of modern ideas and problems that it would be an attractive study even apart from the special interest which attaches to it from the point of view of religious and idealistic conceptions of the universe.Both Liebig and Johannes Müller remained vitalists, notwithstanding the discovery of the synthesis of urea and the increasing number of organic compounds which were built up artificially by purely chemical methods. It was only about the middle of the last century that the younger generation, under the leadership, in Germany, of Du Bois-Reymond in particular, went over[pg 237]decidedly to the mechanistic side, and carried the doctrines of the school to ever fresh victories. But opposition was not lacking from the outset, though it was restrained and cautious.Virchow's“Caution”.Here, as also in regard to“Darwinism,”which was advanced about the same time, the typical advocate of“caution”was Rudolf Virchow. His doubts and reservations found utterance very soon after the theory itself had been promulgated. In his“Cellular Pathologie,”76and in an essay on“The Old Vitalism and the New,”77he puts in a word for avis vitalis. The old vitalism, he declared, had been false because it assumed, not avis, but aspiritus vitalis. The substances in animate and in inanimate bodies have undoubtedly absolutely the same properties. Nevertheless,“we must at once rid ourselves of the scientific prudery of regarding the processes of life solely as the mechanical result of the molecular forces inherent in their constituent bodily parts.”The essential feature of life is a derived and communicated forceadditionalto the molecular forces. Whence it comes we are not told. He glided all round the problem with platitudinarian expressions, which were intended to show his own adherence as a matter of course to the new biological school, and which revealed at the same time his striking incapacity for defining a[pg 238]problem with any precision. At a“certain period in the evolution of the earth”this force arose, as the ordinary mechanical movements“swung over”into the vital. But it is thus a special form of movement, which detaches itself from the great constants of general movement, and runs its course alongside of, and in constant relation to, these. (Did ever vitalist assert more?) After thus preparing the way for a return of the veering process at a particular stage of evolution, and giving the necessary assurances against the“diametrically opposed dualistic position,”Virchow employs almost all the arguments against the mechanical theory which vitalists have ever brought forward. Even the catalytic properties of ferments are above the“ordinary”physical and chemical forces. The movement of crystallisation, too, cannot be compared with the vital movement. For vital force is not immanent in matter, but is always the product of previous life.78In the simplest processes of growth and nutrition thevis vitalisplays its vitalrôle. This is true in a much greater degree of the processes of development and morphogenesis. In the phenomena of irritability life reveals its spontaneity through“responses,”and so on.“Peu d'anatomie pathologique éloigne du vitalisme, beaucoup d'anatomie pathologique y ramène.”It is impossible to make much of this position. It leaves the theory with one of the opposing parties, the[pg 239]practice with the other, and the problem just where it was before.Preyer's Position.Along with Virchow, we must name another of the older generation, the physiologist William Preyer, who combated“vitalism,”“dualism,”and“mechanism”with equal vehemence, and issued a manifesto, already somewhat solemn and official, against“vital force.”And yet he must undoubtedly be regarded as a vitalist by mechanists and vitalists alike.79He is more definite than Virchow, for he does not content himself with general statements as to the“origin”of vital force, and of the“swinging over”of the merely mechanical energies into the domain of the vital, but holds decidedly to the propositionomne vivum e vivo. He therefore maintains that life has always existed in the cosmos, and entirely rejects spontaneous generation.The fallacy, he says, of the mechanistic claims was due to the increasing number of physical explanations of isolated vital phenomena, and of imitations of the chemical products of organic metabolism. A wrong conclusion was drawn from these.“Any one who hopes to deduce from the chemical and physical properties of the fertilised egg the necessity that an animal, tormented by hunger and love must, after a[pg 240]certain time, arise therefrom, has a pathetic resemblance to the miserable manufacturers of homunculi.”Life is one of the underivable and inexplicable fundamental functions of universal being. From all eternity life has only been produced from life.As Preyer accepts the Kant-Laplace theory of the origin of our earth from the sun, he reaches ideas which have points of contact with the“cosmo-organic”ideas of Fechner. Life was present even when the earth was a fiery fluid sphere, and was possibly more general and more abundant then than it is now. And life as we know it may only be a smaller and isolated expression of that more general life.80[pg 241]Among the younger generation of specialists, those most often quoted as opponents of the mechanical theory are probably Bunge, Rindfleisch, Kerner von Marilaun, Neumeister and Wolff. A special group among them, not very easy to classify, may be called the Tectonists. Associated with them is Reinke's“Theory of Dominants.”Driesch started from their ranks, and is a most interesting example of consistent development from a recognition of the impossibilities of the mechanistic position to an individually thought-out vitalistic theory. Hertwig, too, takes a very definite position of his own in regard to these matters. Perhaps the most original contribution in the whole field is Albrecht's“Theory of Different Modes of Regarding Things.”We may close the list with the name of K. C. Schneider, who has carried these modern ideas on into metaphysical speculation. Several others might be mentioned along with and connecting these representative names.81[pg 242]The Position Of Bunge and Other Physiologists.For a long time one of the most prominent figures in the controversy was Prof. G. Bunge, of Basle, who was one of the first modern physiologists to champion vitalism, and who has tried to show by analogies and illustrations what is necessarily implied in vital activity.82The mechanical reduction of vital phenomena to physico-chemical forces, he says, is impossible, and becomes more and more so as our knowledge deepens. He brings forward a series of convincing examples of the way in which apparent mechanical explanations have broken down. The absorption of the chyle through the walls of the intestine seemed to be a mechanically intelligible process[pg 243]of osmosis and diffusion. But in reality it proves to be rather a process of selection on the part of the epithelial cells of the intestine, analogous to the selection and rejection exercised elsewhere by unicellular organisms. In the same way the epithelial cells of the mammary glands“select”the suitable substances from the blood. It is impossible to explain in a mechanical way the power which directs the innumerable different chemical and physical processes within the organism, whether they be the bewilderingly purposeful reactions in the individual life of the cell, which seem to point to psychic processes within the plasm, or the riddles of development and of inheritance in particular; for how can a spermatozoon, so small that 500 millions can lie on a cubic line, be the bearer of all the peculiarities of the father to the son?In Lecture III. Bunge defines his attitude towards the law of the conservation of energy. In so doing he unconsciously follows the lines laid down by Descartes. All processes of movement and all functions exhibited by the living substance are the results of the accumulated potential energies, and the sums of work done and energy utilised remain the same. But the liberation and the direction of these energies is a factor by itself, which neither increases nor diminishes the sum of energies.“Occasiones”and“causæ”are brought into the field once more. The energies effect the phenomena, but they require“occasiones”to liberate them—thus a stone may fall to the ground by virtue of the[pg 244]potential energies stored in it at the time of its suspension, but it cannot fall until the thread by which it hangs has been cut. The function of the“occasio”itself is something quite outside of and without relation to the effect caused; it is a matter of indifference whether the thread be cut gently through with a razor or shot in two with a cannon ball.Kassowitz83is an instructive example of how much the force of criticism has been recognised even by those occupying a convinced mechanical point of view. He subjects all the different theories which attempt to explain the chief vital phenomena in mechanical terms to a long and exhaustive examination. The theories of the organism as a thermodynamic engine, osmotic theories, theories of ferments, interpretations in terms of electro-dynamics and molecular-physics—are all examined (chap. iv.); and the failure of all these hypotheses, notwithstanding the enormous amount of ingenuity expended in their construction, is summed up in an emphatic“Ignoramus.”“The failure is a striking one,”and it is frankly admitted that, in strong contrast to the earlier mood of confident hope, there now prevails a mood of resignation in regard to the mechanical-experimental investigation of the living organism, and that even specialists of the first rank are finding that they have to reckon again seriously with vital force. This breakdown and these admissions do not exactly tend to prejudice us in favour of the[pg 245]author's own attempt to substantiate new mechanical theories.In the comprehensive text-book of physiological chemistry by R. Neumeister, the mechanical standpoint seemed to be adhered to as the ideal. But the same writer forsakes it entirely, and disputes it energetically in his most recent work,“Betrachtungen über das Wesen der Lebenserscheinungen”84(“Considerations as to the Nature of Vital Phenomena”). He passes over all the larger problems, such as those of development, inheritance, regeneration, and confines himself in the main to the physiological functions of protoplasm, especially to those of the absorption of food and metabolism. And he shows, by means of illustrations, in part Bunge's, in part his own, and in close sympathy with Wundt's views, that even these vital phenomena cannot possibly be explained in terms of chemical affinity, physical osmosis, and the like. In processes of selection (such as, for instance, the excretion of urea and the retention of sugar in the blood), the“aim is obvious, but the causes cannot be recognised.”Psychical processes play a certain part in the functions of protoplasm in the form of qualitative and quantitative sensitiveness. All the mechanical processes in living organisms are initiated and directed by psychical processes. Physical, chemical and mechanical laws are perfectly valid, but they are not absolutely dominant. Living matter is to be defined as“a unique chemical[pg 246]system, the molecules of which, by their peculiar reciprocal action, give rise to psychical and material processes in such a way that the processes of the one kind are always causally conditioned and started by those of the other kind.”The psychical phenomena he regards as transcendental, supernatural,“mystical,”yet unquestionably also subject to a strict causal nexus, although the causality must remain for ever concealed. Starting from this basis, he analyses and rejects the explanations which have been offered in terms of the analogy of ferments, enzymes, or catalytic processes. In particular, he disputes Ostwald's“Energismus”and Verworn's Biogen hypothesis.85[pg 247]Among the vitalists of to-day, one of the most frequently cited, perhaps, except Driesch the most frequently cited, is G. Wolff, aPrivatdozent, formerly at Würzburg, now at Basle. He has only published short lectures and essays, and these deal not so much with the mechanical theory as with Darwinism.86But in these writings his main argument is that of his concluding chapter: the spontaneous adaptiveness of the organism, which nullifies all contingent theories to explain the purposiveness in ontogeny and phylogeny. And in his lecture,“Mechanismus und Vitalismus,”87in which he directs his attention especially to criticising Bütschli's defence of mechanism, the only problem to which prominence is given is the one with which we are here concerned. In spite of their brevity, these writings have given rise to much controversy, because what is peculiar to the two standpoints is described with precision, and the problem is clearly defined. His criticism had its starting-point in, and received a special impulse from an empirical proof, due to a very happy experiment of his own, of the marvellous regenerative capacity, and the inherent purposive[pg 248]activity of the living organism. He succeeded in proving that if the lens of the eye of the newt be excised, it may be regrown. The importance of this fact is greatly increased if we trace out in detail the various impossible rival mechanical interpretations which have grown up around this interesting case. As Driesch says,“It is not a restoration starting from the wound, it is a substitution starting from a different place.”
Chapter IX. Criticism Of Mechanical Theories.In attempting to define our attitude to the mechanical theory of life, we have first of all to make sure that we have a right to take up a definite position at all. We should have less right, or perhaps none, if this theory of life were really of a purely“biological”nature, built up entirely from the expert knowledge and data which the biologist alone possesses. But the principles, assumptions, supplementary ideas and modes of expression along all the six lines we have discussed, the style and method according to which the hypothesis is constructed, the multitude of separate presuppositions with which it works, and indeed everything that helps to build up and knit the biological details into a scientific hypothesis, are the materials of rational synthesis in general, and as such are subject to general as well as to biological criticism. What is there, for instance, in Weismann's ingenious biophor-theory that can be called specifically biological, and not borrowed from other parts of the scientific system?One advantage, indeed, the biologist always has in this matter, apart from his special knowledge; that is,[pg 221]the technical instinct, the power of scenting out, so to speak, and immediately feeling the importance of the facts pertaining to his own discipline. It is this that gives every specialist the advantage over the layman in dealing with the data of his own subject. This power of instinctively appraising facts, which develops in the course of all special work, can, for instance in hypotheses in the domain of history, transform small details, which to the layman seem trivial, into weighty arguments. Similarly it may be that the success of the mechanical interpretation in regard to isolated processes may make its validity for many other allied processes certain, even though there is no precise proof of this. But we cannot regard this as a final demonstration of the applicability of the mechanical theory, since the same technical instinct in other experts leads them to reject the whole hypothesis.But here we are met with something surprising. May it not be that while we are impelled on general grounds to contend against the mechanical interpretation of vital phenomena, we are not so impelled onreligiousgrounds? May it not be that the instinct of the religious consciousness is misleading when it impels us—as probably every one will be able to certify from his own experience—to rebel against this mechanisation of life, the mechanical solution of its mysteries? Lotze, the energetic antagonist of“vital force,”the founder of the mechanical theory of vital processes, was himself a theist, and was so far from recognising any contradiction[pg 222]between the mechanical point of view and the Christian belief in God, that he included the former without ceremony in his theistic philosophical speculations. His view has become that of many theologians, and is often expressed in a definition of the boundaries between theology and natural science. According to the idea which was formulated by Lotze, and developed by others along his lines, the matter is quite simple. The interest which religion has in the processes of nature is at once and exclusively to be found in teleology. Are there purposes, plans, and ideas which govern and give meaning to the whole? The interest of natural science is purely in recognising inviolable causality; every phenomenon must have its compelling and sufficient reason in the system of causes preceding it. All that is and happens is absolutely determined by its causes, and nothing, nocausæ finalesfor instance, can co-operate with these causes in determining the result. But, as Lotze says, and as we have repeatedly pointed out, causal explanation does not exclude a consideration from the point of view of purpose, and the mechanical interpretation does not do so either. For this is nothing more than the causal explanation itself, only carried to complete consistency and definiteness. Purposes and ideas are not efficient causes but results. Where, for instance, there is a controlled purposive occurrence, the“purpose”nowhere appears as a factor co-operating with the series of causes, for these follow according to strict law, and the“purpose”reveals itself at the close[pg 223]of the series, as the result of a closed causal nexus, complete in itself, always provided that the initial links in the chain have been accurately estimated. The same is true of the processes of life. They are the ultimate result, strictly necessary and sufficiently accounted for in terms of mechanical sequence, of a long chain of causes whose initial links imply a definite constitution which could not be further reduced. Whether this ultimate result is merely a result or whether it is also a“purpose”is a question which, as we have seen twice already, it is wholly beyond the power of the causal mode of interpretation to answer. Given that an infinite intelligence in the world wished to realise purposes without instituting them as directly accomplished, but by letting them express themselves through a gradual“becoming,”the method would be exactly what is shown in the mechanical theory of life, that is, the primitive data and starting-points would have inherent in them a peculiar constitution and a rigidly inexorable orderliness of causal sequence. And Lotze emphasises that it would also be worthier of God to achieve the greatest by means of the simplest, and to work out the realisation of His eternal purposes according to the strict inevitableness of mechanism, than to attain His ends through the complicated means, the adventitious aids, and all the irregularities implied in the incommensurable activities of a“vital force.”(“God needs no minor gods.”)To Lotze himself these original data and starting[pg 224]points are the primitive forms of life, which, according to his view, are directly“given,”and cannot be referred back to anything else (except to“creation”). But it is obvious that his view can be enlarged and extended so as to refer the derivation of the whole animate world to the original raw materials of the cosmos (energy, matter, or whatsoever they may be), and to the orderly process by which these materials were combined in various configurations to form the chemical elements, the chemical compounds, living proteids, the first cell, and the whole series of higher forms. If this nexus has taken place, it is nothing else than the transformation of the“potential”into the“actual”through strict causality. And if this actuality proves itself to have claims, because of its own intrinsic worth, to be considered as intelligent“purpose,”the whole system of means, including the starting-point, can be recognised as the means to an end, and the original wisdom and the intelligence which ordained the purpose is only glorified the more through the great simplicity, the rational comprehensibility, and the inexorable necessity of the system, which excludes all chance, and therewith all possibility of error.This extension of Lotze's reconciliation of the mechanical causal with the teleological point of view is impressive and, as far as it goes, also quite convincing. It will never be given up, even if the point of view should change somewhat. And we have already seen that it is quite sufficient as long as we are dealing[pg 225]only with the question of teleology. But we must ask whether religion will be satisfied with“teleology”alone, or whether this is even the first requirement that it makes in regard to natural phenomena. We have already asked the question and attempted to clear the ground for an answer. Let us try to make it more definite.Many people will have a certain uneasiness in regard to the Lotzian ideas; they will be unable to rid themselves of a feeling that this way of looking at things is only apis allerfor the religious point of view, and that the fundamental requirements of religious feeling receive very inadequate satisfaction on this method. The world of life which has arisen thus is altogether too rational and transparent. It is calculable and mathematical. It satisfies well enough the need for teleology, and with that the need for a supreme, universally powerful and free intelligence; but it gives neither support nor nourishment to the essential element in religious feeling, through which alone faith becomes in the strict sense religious. Religion, even Christian religion, is, so to speak, a stratified structure, a graduated pyramid, expressing itself, at its second (and undoubtedly higher) level, in our recognition of purpose, the rationality of the world, our own spiritual and personal being and worth, but implying at its basis an inward sense of the mysterious, a joy in that which is incommensurable and unspeakable, which fills us with awe and devotion. And religion at the second[pg 226]stage must not sweep away the essence of the stage below, but must include it, at the same time informing it with new significance. Whoever does not possess his religion in this way will agree with, and will be quite satisfied with the Lotzian standpoint. But to any one who has experience of the most characteristic element in religion, it will be obvious that there must be a vague but deep-rooted antipathy between religion and the mathematical-mechanical conception of things. Evidence of the truth of this is to be found in the instinctive perceptions and valuations which mark even the naïve expressions of the religious consciousness.75For it is in full sympathy with a world which is riddled with what is inconceivable and incommensurable, in full sympathy with every evidence of the existence of such an element in the world of nature and mind, and therefore with every proof that the merely mechanical theory has its limits, that it does not suffice, and that its very insufficiency is a proof that the world is and remains in its depths mysterious. Now we have already said that the true sphere for such feeling is not the outer court[pg 227]of nature, but within the realm of the emotional life and of history, and, on the other hand, that even if the attempt to trace life back to the simpler forces of nature were successful, we should still be confronted with the riddle of the sphinx. But any one who would say frankly what he felt would at once be obliged to admit that the religious sense is very strongly stirred by the mystery of vital phenomena, and that in losing this he would lose a domain very dear to him. These sympathies and antipathies are in themselves sufficient to give an interest to the question of the insufficiency of the mechanical view of things.For it is by no means the case that the mechanical theory, with its premisses and principles, is the interpretation that best fits the facts, and that most naturally arises out of a calm consideration of the animate world. It is an artificial scheme, and astonishing energy has been expended on the attempt to fit it to the actual world, that it may make this orderly and translucent. It certainly yields this service so far, but not without often becoming a kind of strait-jacket, and revealing itself as an artificiality. In so far as the special problems of biology are concerned, we shall afterwards follow our previous method of taking our orientation from those specialists in the subject who, in reaction from the one-sidedness of the mechanical doctrine, have founded the“neo-vitalism”of to-day. Here we are only concerned with the generalities and presuppositions of the theory.[pg 228]We must dispute even the main justification of the theory, which is sought for in the old maxim of parsimony in the use of principles of explanation (entia, and alsoprincipia, præter necessitatem non esse multiplicanda), and in Kant's“regulative principle,”that science must proceed as if everything could ultimately be explained in terms of mechanism. For surely our task is to try to explain things, not at any cost with the fewest possible principles, but rather with the aid of those principles which appear most correct. If nature is not fundamentally simple, then it is not scientific but unscientific to simplify it theoretically. And the proposition bracketed above has its obvious converse side, that while entities and principles must not be multiplied except when it is necessary, on the other hand their number must not be arbitrarily lessened. To proceed according to the fundamental maxims of the mechanistic view can only be wholesome for a time and, so to speak, for pædagogical reasons. To apply them seriously and permanently would be highly injurious, for, by prejudging what is discoverable in nature, it would tend to prevent the calm, objective study of things which asks for nothing more than to see them as they are. It would thus destroy the fineness of our appreciation of what there really is in nature. This is true alike of forcible attempts to reduce the processes of life to mechanical processes, and of the Darwinian doctrine of the universal dominance of utility. Both bear unmistakably the stamp of foregone conclusions, and betray[pg 229]a desire for the simplest, rather than for the most correct principles of interpretation.There is one point which presses itself on the notice even of outsiders, and is probably realised even more keenly by specialists. The confidence of the supporters of the mechanical theories of earlier days, from Descartes onward, that animals and the bodies of men were machines, mechanical automata, down to the mechanical theories of Lamettrie and Holbach, ofl'homme machine, and of thesystème de la nature, was at least as great as, probably greater than, that of the supporters of the modern theories. Yet how naïve and presumptuous seem the crude and wooden theories upon which the mechanical system was formerly built up, and how falsely interpreted seem the physiological and other facts which lent them support, when seen in the light of our modern physiological knowledge. Vaucanson's or Drozsch's duck-automaton or clockwork-man, with which the mechanical theorists of bygone days amused themselves, would not go far to encourage the physiologist of to-day to pursue his mechanical studies, but would rather throw a vivid light on the impossibility of comparing the living“machine”with machines in the usual sense. For things emphatically do not happen within the living organism in the same way as in the automatic duck, and the more exact the resemblance to the functions of a“real”duck became, the more did the system of means by which the end was attained become unlike vital processes. It is difficult to resist the[pg 230]impression that in another hundred years,—perhaps again from the standpoint of new and definitely accepted mechanical explanations,—people will regard our developmental mechanics, cellular mechanics, and other vital mechanics much in the same way as we now look on Vaucanson's duck.Associated or even identical with this is the fact that in proportion as mechanical interpretation advances, the difficulties it has to surmount continually crop up anew. Processes which seem of the simplest kind and the most likely to be capable of purely mechanical explanation, processes such as those of assimilation, digestion, respiration, for which it was believed that exact parallels existed in the purely mechanical domain, as, for instance, in the osmotic processes of porous membranes, are seen when closely scrutinised as they occur in the living body to be extremely complex; in fact they have to be transferred“provisionally”from the mechanical to the vital rubric. To this category belong the whole modern development of the cell-theory, which replaces the previouslysinglemechanism in the living body by millions of them, every one of which raises as many problems as the one had done in the days of cruder interpretation. Every individual cell, as it appears to our understanding to-day, is at least as complicated a riddle as the whole organism formerly appeared.But further: the modern development of biology has emphasised a special problem, which was first formulated[pg 231]by Leibnitz (though it is in antithesis to his fundamental Monad-theory), and which appears incapable of solution on mechanical lines. Leibnitz declared living beings to be“machines,”but machines of a peculiar kind. Even the most complicated machine, in the ordinary sense, consists of a combination of smaller“machines,”that is to say, of wheels, systems of levers, &c., of a simpler kind. And these sub-machines may in their turn consist of still simpler ones, and so on. But ultimately a stage is reached when the component parts are homogeneous, and cannot be analysed into simpler machines. It is otherwise with the organism. According to Leibnitz it consists of machines made up of other machines, and so on, into the infinitely little. However far we can proceed in our analysis of the parts, we shall still find that they are syntheses, made up of most ingeniously complex component parts, and this as far as our powers of seeing and distinguishing will carry us. That is to say: organisation is continued on into the infinitely little.Leibnitz's illustration of the fish-pond is well known. He could have no better corroboration of his theory than the results of modern investigation afford. His doctrine of the continuation of organisation downwards into ever smaller expression is confirmed to a certain extent even by anatomy. By analysing structural organisation down to cells a definite point seemed to have been reached. But it now appears that at that point the problem is only beginning. One organisation is made[pg 232]up of other organisations—cells, protoplasm, nucleus, nucleolus, centrosomes, and so on, according to the power of the microscope; and these structures, instead of explaining the vital functions of growth, development, multiplication by division, and the rest, simply repeat them on a smaller scale, and are thus in their turn living units, the aggregation of which is illustrated better by the analogy of a social organism than by that of a mechanical structure.In order to follow the mechanical explanation along the six lines we have previously indicated, we shall, as we have already said, entrust ourselves to the specialists who are on the opposite side. The difficulties and objections which the mechanical theory has to face have forced themselves insistently upon us even in the course of a short sketch such as has just been given, but they will be clearly realised if we approach them from the other side. But, first of all, a word as to the fundamental and, it is alleged, unassailable doctrine on which the theory as a whole is based, the“law of the conservation of energy.”The appeal to this, at any rate in the way in which it is usually made, is apt to be so distorted that the case must first be clearly stated before we can get further with the discussion.The Law of the Conservation of Energy.Helmholtz's proof established mathematically what Kant had already, by direct insight, advanced as anà priorifundamental axiom: that in any given system[pg 233]the sum of energy can neither increase (impossibility of aperpetuum mobile) nor diminish (there is no disappearance of energy, but only transformation into another form). But even the vitalist had no need to deny this proposition. The“energy”which is required for the work of directing, setting agoing, changing and rearranging the chemico-physical processes in the body, and bringing about the effective reactions to stimuli which result in“development,”“transmission,”“regeneration,”and so on—if indeed any energy is required—of course could not come“from within”as a spontaneous increase of the existing sum of energy—that would, indeed, be a magical becoming out of nothing!—but must naturally be thought of as coming“from without.”The appeal to the law of the conservation of energy is therefore in itself irrelevant; but it conceals behind it an assertion of a totally different kind, namely, that in relation to physico-chemical sequences there can be no“without,”nothing transcending them—an assertion which Helmholtz's arguments cannot and were never intended to establish. But before any definite attitude to this newly imported assertion could be taken up, it would require to be distinctly defined, and that would lead us at once into all the depths of epistemological discussion. Here, therefore, we can only say so much: If this assertion is accepted it is well to see where it carries us; namely, back to the first-described naïve standpoint, which, without critical scruples, quite seriously accepts the world as it appears to it for the[pg 234]reality, and quite seriously speaks of an infinity lying in time behind us—and therefore come to an end—and is not in the least disturbed from its“dogmatic slumber”by this or any of the other great antinomies of our conception of the universe. And it remains, too, for this standpoint to come to terms with the fact that, in voluntary actions, of which we have the most direct knowledge, we have through our will the power of intervention in the physico-chemical nexus of our bodily energies—a fact which implies the existence of a“without,”from which interpolations or influences may flow into the physico-chemical system, even if there be none in regard to the domain of“vital”phenomena. And we should require to find out through what parallelistic or abruptly idealistic system the“without”was done away with in this case. For if a transcendental basis, or reverse side, or cause of things, be admitted—even if only in the form of our materialistic popular metaphysics (the“substance”of Haeckel's“world-riddle”)—then a“without,”from which primarily the cosmic system with its constant sum of matter and energy is explained, is also admitted, and it is difficult to see why it should have exhausted itself in this single effort.Criticisms of the Mechanistic Theory of Life.The course of the mechanistic theory of life has been surprisingly similar to that of its complement, the theory of the general evolution of the organic world.[pg 235]The two great doctrines of the schools, Darwinism on the one hand, the mechanical interpretation of life on the other, are both tottering, not because of the criticism of outsiders, but of specialists within the schools themselves. And the interest which religion has in this is the same in both cases: the transcendental nature of things, the mysterious depth of appearance, which these theories denied or obscured, become again apparent. The incommensurableness and mystery of the world, which are, perhaps, even more necessary to the very life of religion than the right to regard it teleologically, reassert themselves afresh in the all-too-comprehensible and mathematically-formulated world, and re-establish themselves, notwithstanding obstinate and persistent attempts to do away with them. This is perhaps to the advantage of both natural science and religion: to the advantage of religion because it can with difficulty co-exist with the universal dominance of the mathematical way of looking at things; to the advantage of natural science because, in giving up the one-sidedness of the purely quantitative outlook, it does not give up its“foundations,”its“right to exist,”but only apetitio principiiand a prejudice that compelled it to exploit nature rather than to explain it, and to prescribe its ways rather than to seek them out.The reaction from the one-sided mechanical theories shows itself in many different ways and degrees. It may, according to the individual naturalist, affect the[pg 236]theory as a whole, or only certain parts of it, or only particular lines. It starts with mere criticism and with objections, which go no further than saying that“in the meantime”we are still far from having reached a physico-chemical solution of the riddle of life; it may ascend through all stages up to an absolute rejection of the theory as an idiosyncrasy of the time which impedes the progress of investigation, and as an uncritical prejudice of the schools. It may remain at the level of mere protest, and content itself with demonstrating the insufficiency of the mechanical explanation, without attempting to formulate any independent theory for the domain of the vital; or it may construct a specifically biological theory, claiming independence amid other disciplines, and basing this claim on the autonomy of vital processes; or it may widen out deliberately into metaphysical study and speculation. Taken at all these levels it presents such a complete section of the trend of modern ideas and problems that it would be an attractive study even apart from the special interest which attaches to it from the point of view of religious and idealistic conceptions of the universe.Both Liebig and Johannes Müller remained vitalists, notwithstanding the discovery of the synthesis of urea and the increasing number of organic compounds which were built up artificially by purely chemical methods. It was only about the middle of the last century that the younger generation, under the leadership, in Germany, of Du Bois-Reymond in particular, went over[pg 237]decidedly to the mechanistic side, and carried the doctrines of the school to ever fresh victories. But opposition was not lacking from the outset, though it was restrained and cautious.Virchow's“Caution”.Here, as also in regard to“Darwinism,”which was advanced about the same time, the typical advocate of“caution”was Rudolf Virchow. His doubts and reservations found utterance very soon after the theory itself had been promulgated. In his“Cellular Pathologie,”76and in an essay on“The Old Vitalism and the New,”77he puts in a word for avis vitalis. The old vitalism, he declared, had been false because it assumed, not avis, but aspiritus vitalis. The substances in animate and in inanimate bodies have undoubtedly absolutely the same properties. Nevertheless,“we must at once rid ourselves of the scientific prudery of regarding the processes of life solely as the mechanical result of the molecular forces inherent in their constituent bodily parts.”The essential feature of life is a derived and communicated forceadditionalto the molecular forces. Whence it comes we are not told. He glided all round the problem with platitudinarian expressions, which were intended to show his own adherence as a matter of course to the new biological school, and which revealed at the same time his striking incapacity for defining a[pg 238]problem with any precision. At a“certain period in the evolution of the earth”this force arose, as the ordinary mechanical movements“swung over”into the vital. But it is thus a special form of movement, which detaches itself from the great constants of general movement, and runs its course alongside of, and in constant relation to, these. (Did ever vitalist assert more?) After thus preparing the way for a return of the veering process at a particular stage of evolution, and giving the necessary assurances against the“diametrically opposed dualistic position,”Virchow employs almost all the arguments against the mechanical theory which vitalists have ever brought forward. Even the catalytic properties of ferments are above the“ordinary”physical and chemical forces. The movement of crystallisation, too, cannot be compared with the vital movement. For vital force is not immanent in matter, but is always the product of previous life.78In the simplest processes of growth and nutrition thevis vitalisplays its vitalrôle. This is true in a much greater degree of the processes of development and morphogenesis. In the phenomena of irritability life reveals its spontaneity through“responses,”and so on.“Peu d'anatomie pathologique éloigne du vitalisme, beaucoup d'anatomie pathologique y ramène.”It is impossible to make much of this position. It leaves the theory with one of the opposing parties, the[pg 239]practice with the other, and the problem just where it was before.Preyer's Position.Along with Virchow, we must name another of the older generation, the physiologist William Preyer, who combated“vitalism,”“dualism,”and“mechanism”with equal vehemence, and issued a manifesto, already somewhat solemn and official, against“vital force.”And yet he must undoubtedly be regarded as a vitalist by mechanists and vitalists alike.79He is more definite than Virchow, for he does not content himself with general statements as to the“origin”of vital force, and of the“swinging over”of the merely mechanical energies into the domain of the vital, but holds decidedly to the propositionomne vivum e vivo. He therefore maintains that life has always existed in the cosmos, and entirely rejects spontaneous generation.The fallacy, he says, of the mechanistic claims was due to the increasing number of physical explanations of isolated vital phenomena, and of imitations of the chemical products of organic metabolism. A wrong conclusion was drawn from these.“Any one who hopes to deduce from the chemical and physical properties of the fertilised egg the necessity that an animal, tormented by hunger and love must, after a[pg 240]certain time, arise therefrom, has a pathetic resemblance to the miserable manufacturers of homunculi.”Life is one of the underivable and inexplicable fundamental functions of universal being. From all eternity life has only been produced from life.As Preyer accepts the Kant-Laplace theory of the origin of our earth from the sun, he reaches ideas which have points of contact with the“cosmo-organic”ideas of Fechner. Life was present even when the earth was a fiery fluid sphere, and was possibly more general and more abundant then than it is now. And life as we know it may only be a smaller and isolated expression of that more general life.80[pg 241]Among the younger generation of specialists, those most often quoted as opponents of the mechanical theory are probably Bunge, Rindfleisch, Kerner von Marilaun, Neumeister and Wolff. A special group among them, not very easy to classify, may be called the Tectonists. Associated with them is Reinke's“Theory of Dominants.”Driesch started from their ranks, and is a most interesting example of consistent development from a recognition of the impossibilities of the mechanistic position to an individually thought-out vitalistic theory. Hertwig, too, takes a very definite position of his own in regard to these matters. Perhaps the most original contribution in the whole field is Albrecht's“Theory of Different Modes of Regarding Things.”We may close the list with the name of K. C. Schneider, who has carried these modern ideas on into metaphysical speculation. Several others might be mentioned along with and connecting these representative names.81[pg 242]The Position Of Bunge and Other Physiologists.For a long time one of the most prominent figures in the controversy was Prof. G. Bunge, of Basle, who was one of the first modern physiologists to champion vitalism, and who has tried to show by analogies and illustrations what is necessarily implied in vital activity.82The mechanical reduction of vital phenomena to physico-chemical forces, he says, is impossible, and becomes more and more so as our knowledge deepens. He brings forward a series of convincing examples of the way in which apparent mechanical explanations have broken down. The absorption of the chyle through the walls of the intestine seemed to be a mechanically intelligible process[pg 243]of osmosis and diffusion. But in reality it proves to be rather a process of selection on the part of the epithelial cells of the intestine, analogous to the selection and rejection exercised elsewhere by unicellular organisms. In the same way the epithelial cells of the mammary glands“select”the suitable substances from the blood. It is impossible to explain in a mechanical way the power which directs the innumerable different chemical and physical processes within the organism, whether they be the bewilderingly purposeful reactions in the individual life of the cell, which seem to point to psychic processes within the plasm, or the riddles of development and of inheritance in particular; for how can a spermatozoon, so small that 500 millions can lie on a cubic line, be the bearer of all the peculiarities of the father to the son?In Lecture III. Bunge defines his attitude towards the law of the conservation of energy. In so doing he unconsciously follows the lines laid down by Descartes. All processes of movement and all functions exhibited by the living substance are the results of the accumulated potential energies, and the sums of work done and energy utilised remain the same. But the liberation and the direction of these energies is a factor by itself, which neither increases nor diminishes the sum of energies.“Occasiones”and“causæ”are brought into the field once more. The energies effect the phenomena, but they require“occasiones”to liberate them—thus a stone may fall to the ground by virtue of the[pg 244]potential energies stored in it at the time of its suspension, but it cannot fall until the thread by which it hangs has been cut. The function of the“occasio”itself is something quite outside of and without relation to the effect caused; it is a matter of indifference whether the thread be cut gently through with a razor or shot in two with a cannon ball.Kassowitz83is an instructive example of how much the force of criticism has been recognised even by those occupying a convinced mechanical point of view. He subjects all the different theories which attempt to explain the chief vital phenomena in mechanical terms to a long and exhaustive examination. The theories of the organism as a thermodynamic engine, osmotic theories, theories of ferments, interpretations in terms of electro-dynamics and molecular-physics—are all examined (chap. iv.); and the failure of all these hypotheses, notwithstanding the enormous amount of ingenuity expended in their construction, is summed up in an emphatic“Ignoramus.”“The failure is a striking one,”and it is frankly admitted that, in strong contrast to the earlier mood of confident hope, there now prevails a mood of resignation in regard to the mechanical-experimental investigation of the living organism, and that even specialists of the first rank are finding that they have to reckon again seriously with vital force. This breakdown and these admissions do not exactly tend to prejudice us in favour of the[pg 245]author's own attempt to substantiate new mechanical theories.In the comprehensive text-book of physiological chemistry by R. Neumeister, the mechanical standpoint seemed to be adhered to as the ideal. But the same writer forsakes it entirely, and disputes it energetically in his most recent work,“Betrachtungen über das Wesen der Lebenserscheinungen”84(“Considerations as to the Nature of Vital Phenomena”). He passes over all the larger problems, such as those of development, inheritance, regeneration, and confines himself in the main to the physiological functions of protoplasm, especially to those of the absorption of food and metabolism. And he shows, by means of illustrations, in part Bunge's, in part his own, and in close sympathy with Wundt's views, that even these vital phenomena cannot possibly be explained in terms of chemical affinity, physical osmosis, and the like. In processes of selection (such as, for instance, the excretion of urea and the retention of sugar in the blood), the“aim is obvious, but the causes cannot be recognised.”Psychical processes play a certain part in the functions of protoplasm in the form of qualitative and quantitative sensitiveness. All the mechanical processes in living organisms are initiated and directed by psychical processes. Physical, chemical and mechanical laws are perfectly valid, but they are not absolutely dominant. Living matter is to be defined as“a unique chemical[pg 246]system, the molecules of which, by their peculiar reciprocal action, give rise to psychical and material processes in such a way that the processes of the one kind are always causally conditioned and started by those of the other kind.”The psychical phenomena he regards as transcendental, supernatural,“mystical,”yet unquestionably also subject to a strict causal nexus, although the causality must remain for ever concealed. Starting from this basis, he analyses and rejects the explanations which have been offered in terms of the analogy of ferments, enzymes, or catalytic processes. In particular, he disputes Ostwald's“Energismus”and Verworn's Biogen hypothesis.85[pg 247]Among the vitalists of to-day, one of the most frequently cited, perhaps, except Driesch the most frequently cited, is G. Wolff, aPrivatdozent, formerly at Würzburg, now at Basle. He has only published short lectures and essays, and these deal not so much with the mechanical theory as with Darwinism.86But in these writings his main argument is that of his concluding chapter: the spontaneous adaptiveness of the organism, which nullifies all contingent theories to explain the purposiveness in ontogeny and phylogeny. And in his lecture,“Mechanismus und Vitalismus,”87in which he directs his attention especially to criticising Bütschli's defence of mechanism, the only problem to which prominence is given is the one with which we are here concerned. In spite of their brevity, these writings have given rise to much controversy, because what is peculiar to the two standpoints is described with precision, and the problem is clearly defined. His criticism had its starting-point in, and received a special impulse from an empirical proof, due to a very happy experiment of his own, of the marvellous regenerative capacity, and the inherent purposive[pg 248]activity of the living organism. He succeeded in proving that if the lens of the eye of the newt be excised, it may be regrown. The importance of this fact is greatly increased if we trace out in detail the various impossible rival mechanical interpretations which have grown up around this interesting case. As Driesch says,“It is not a restoration starting from the wound, it is a substitution starting from a different place.”
In attempting to define our attitude to the mechanical theory of life, we have first of all to make sure that we have a right to take up a definite position at all. We should have less right, or perhaps none, if this theory of life were really of a purely“biological”nature, built up entirely from the expert knowledge and data which the biologist alone possesses. But the principles, assumptions, supplementary ideas and modes of expression along all the six lines we have discussed, the style and method according to which the hypothesis is constructed, the multitude of separate presuppositions with which it works, and indeed everything that helps to build up and knit the biological details into a scientific hypothesis, are the materials of rational synthesis in general, and as such are subject to general as well as to biological criticism. What is there, for instance, in Weismann's ingenious biophor-theory that can be called specifically biological, and not borrowed from other parts of the scientific system?
One advantage, indeed, the biologist always has in this matter, apart from his special knowledge; that is,[pg 221]the technical instinct, the power of scenting out, so to speak, and immediately feeling the importance of the facts pertaining to his own discipline. It is this that gives every specialist the advantage over the layman in dealing with the data of his own subject. This power of instinctively appraising facts, which develops in the course of all special work, can, for instance in hypotheses in the domain of history, transform small details, which to the layman seem trivial, into weighty arguments. Similarly it may be that the success of the mechanical interpretation in regard to isolated processes may make its validity for many other allied processes certain, even though there is no precise proof of this. But we cannot regard this as a final demonstration of the applicability of the mechanical theory, since the same technical instinct in other experts leads them to reject the whole hypothesis.
But here we are met with something surprising. May it not be that while we are impelled on general grounds to contend against the mechanical interpretation of vital phenomena, we are not so impelled onreligiousgrounds? May it not be that the instinct of the religious consciousness is misleading when it impels us—as probably every one will be able to certify from his own experience—to rebel against this mechanisation of life, the mechanical solution of its mysteries? Lotze, the energetic antagonist of“vital force,”the founder of the mechanical theory of vital processes, was himself a theist, and was so far from recognising any contradiction[pg 222]between the mechanical point of view and the Christian belief in God, that he included the former without ceremony in his theistic philosophical speculations. His view has become that of many theologians, and is often expressed in a definition of the boundaries between theology and natural science. According to the idea which was formulated by Lotze, and developed by others along his lines, the matter is quite simple. The interest which religion has in the processes of nature is at once and exclusively to be found in teleology. Are there purposes, plans, and ideas which govern and give meaning to the whole? The interest of natural science is purely in recognising inviolable causality; every phenomenon must have its compelling and sufficient reason in the system of causes preceding it. All that is and happens is absolutely determined by its causes, and nothing, nocausæ finalesfor instance, can co-operate with these causes in determining the result. But, as Lotze says, and as we have repeatedly pointed out, causal explanation does not exclude a consideration from the point of view of purpose, and the mechanical interpretation does not do so either. For this is nothing more than the causal explanation itself, only carried to complete consistency and definiteness. Purposes and ideas are not efficient causes but results. Where, for instance, there is a controlled purposive occurrence, the“purpose”nowhere appears as a factor co-operating with the series of causes, for these follow according to strict law, and the“purpose”reveals itself at the close[pg 223]of the series, as the result of a closed causal nexus, complete in itself, always provided that the initial links in the chain have been accurately estimated. The same is true of the processes of life. They are the ultimate result, strictly necessary and sufficiently accounted for in terms of mechanical sequence, of a long chain of causes whose initial links imply a definite constitution which could not be further reduced. Whether this ultimate result is merely a result or whether it is also a“purpose”is a question which, as we have seen twice already, it is wholly beyond the power of the causal mode of interpretation to answer. Given that an infinite intelligence in the world wished to realise purposes without instituting them as directly accomplished, but by letting them express themselves through a gradual“becoming,”the method would be exactly what is shown in the mechanical theory of life, that is, the primitive data and starting-points would have inherent in them a peculiar constitution and a rigidly inexorable orderliness of causal sequence. And Lotze emphasises that it would also be worthier of God to achieve the greatest by means of the simplest, and to work out the realisation of His eternal purposes according to the strict inevitableness of mechanism, than to attain His ends through the complicated means, the adventitious aids, and all the irregularities implied in the incommensurable activities of a“vital force.”(“God needs no minor gods.”)
To Lotze himself these original data and starting[pg 224]points are the primitive forms of life, which, according to his view, are directly“given,”and cannot be referred back to anything else (except to“creation”). But it is obvious that his view can be enlarged and extended so as to refer the derivation of the whole animate world to the original raw materials of the cosmos (energy, matter, or whatsoever they may be), and to the orderly process by which these materials were combined in various configurations to form the chemical elements, the chemical compounds, living proteids, the first cell, and the whole series of higher forms. If this nexus has taken place, it is nothing else than the transformation of the“potential”into the“actual”through strict causality. And if this actuality proves itself to have claims, because of its own intrinsic worth, to be considered as intelligent“purpose,”the whole system of means, including the starting-point, can be recognised as the means to an end, and the original wisdom and the intelligence which ordained the purpose is only glorified the more through the great simplicity, the rational comprehensibility, and the inexorable necessity of the system, which excludes all chance, and therewith all possibility of error.
This extension of Lotze's reconciliation of the mechanical causal with the teleological point of view is impressive and, as far as it goes, also quite convincing. It will never be given up, even if the point of view should change somewhat. And we have already seen that it is quite sufficient as long as we are dealing[pg 225]only with the question of teleology. But we must ask whether religion will be satisfied with“teleology”alone, or whether this is even the first requirement that it makes in regard to natural phenomena. We have already asked the question and attempted to clear the ground for an answer. Let us try to make it more definite.
Many people will have a certain uneasiness in regard to the Lotzian ideas; they will be unable to rid themselves of a feeling that this way of looking at things is only apis allerfor the religious point of view, and that the fundamental requirements of religious feeling receive very inadequate satisfaction on this method. The world of life which has arisen thus is altogether too rational and transparent. It is calculable and mathematical. It satisfies well enough the need for teleology, and with that the need for a supreme, universally powerful and free intelligence; but it gives neither support nor nourishment to the essential element in religious feeling, through which alone faith becomes in the strict sense religious. Religion, even Christian religion, is, so to speak, a stratified structure, a graduated pyramid, expressing itself, at its second (and undoubtedly higher) level, in our recognition of purpose, the rationality of the world, our own spiritual and personal being and worth, but implying at its basis an inward sense of the mysterious, a joy in that which is incommensurable and unspeakable, which fills us with awe and devotion. And religion at the second[pg 226]stage must not sweep away the essence of the stage below, but must include it, at the same time informing it with new significance. Whoever does not possess his religion in this way will agree with, and will be quite satisfied with the Lotzian standpoint. But to any one who has experience of the most characteristic element in religion, it will be obvious that there must be a vague but deep-rooted antipathy between religion and the mathematical-mechanical conception of things. Evidence of the truth of this is to be found in the instinctive perceptions and valuations which mark even the naïve expressions of the religious consciousness.75For it is in full sympathy with a world which is riddled with what is inconceivable and incommensurable, in full sympathy with every evidence of the existence of such an element in the world of nature and mind, and therefore with every proof that the merely mechanical theory has its limits, that it does not suffice, and that its very insufficiency is a proof that the world is and remains in its depths mysterious. Now we have already said that the true sphere for such feeling is not the outer court[pg 227]of nature, but within the realm of the emotional life and of history, and, on the other hand, that even if the attempt to trace life back to the simpler forces of nature were successful, we should still be confronted with the riddle of the sphinx. But any one who would say frankly what he felt would at once be obliged to admit that the religious sense is very strongly stirred by the mystery of vital phenomena, and that in losing this he would lose a domain very dear to him. These sympathies and antipathies are in themselves sufficient to give an interest to the question of the insufficiency of the mechanical view of things.
For it is by no means the case that the mechanical theory, with its premisses and principles, is the interpretation that best fits the facts, and that most naturally arises out of a calm consideration of the animate world. It is an artificial scheme, and astonishing energy has been expended on the attempt to fit it to the actual world, that it may make this orderly and translucent. It certainly yields this service so far, but not without often becoming a kind of strait-jacket, and revealing itself as an artificiality. In so far as the special problems of biology are concerned, we shall afterwards follow our previous method of taking our orientation from those specialists in the subject who, in reaction from the one-sidedness of the mechanical doctrine, have founded the“neo-vitalism”of to-day. Here we are only concerned with the generalities and presuppositions of the theory.
We must dispute even the main justification of the theory, which is sought for in the old maxim of parsimony in the use of principles of explanation (entia, and alsoprincipia, præter necessitatem non esse multiplicanda), and in Kant's“regulative principle,”that science must proceed as if everything could ultimately be explained in terms of mechanism. For surely our task is to try to explain things, not at any cost with the fewest possible principles, but rather with the aid of those principles which appear most correct. If nature is not fundamentally simple, then it is not scientific but unscientific to simplify it theoretically. And the proposition bracketed above has its obvious converse side, that while entities and principles must not be multiplied except when it is necessary, on the other hand their number must not be arbitrarily lessened. To proceed according to the fundamental maxims of the mechanistic view can only be wholesome for a time and, so to speak, for pædagogical reasons. To apply them seriously and permanently would be highly injurious, for, by prejudging what is discoverable in nature, it would tend to prevent the calm, objective study of things which asks for nothing more than to see them as they are. It would thus destroy the fineness of our appreciation of what there really is in nature. This is true alike of forcible attempts to reduce the processes of life to mechanical processes, and of the Darwinian doctrine of the universal dominance of utility. Both bear unmistakably the stamp of foregone conclusions, and betray[pg 229]a desire for the simplest, rather than for the most correct principles of interpretation.
There is one point which presses itself on the notice even of outsiders, and is probably realised even more keenly by specialists. The confidence of the supporters of the mechanical theories of earlier days, from Descartes onward, that animals and the bodies of men were machines, mechanical automata, down to the mechanical theories of Lamettrie and Holbach, ofl'homme machine, and of thesystème de la nature, was at least as great as, probably greater than, that of the supporters of the modern theories. Yet how naïve and presumptuous seem the crude and wooden theories upon which the mechanical system was formerly built up, and how falsely interpreted seem the physiological and other facts which lent them support, when seen in the light of our modern physiological knowledge. Vaucanson's or Drozsch's duck-automaton or clockwork-man, with which the mechanical theorists of bygone days amused themselves, would not go far to encourage the physiologist of to-day to pursue his mechanical studies, but would rather throw a vivid light on the impossibility of comparing the living“machine”with machines in the usual sense. For things emphatically do not happen within the living organism in the same way as in the automatic duck, and the more exact the resemblance to the functions of a“real”duck became, the more did the system of means by which the end was attained become unlike vital processes. It is difficult to resist the[pg 230]impression that in another hundred years,—perhaps again from the standpoint of new and definitely accepted mechanical explanations,—people will regard our developmental mechanics, cellular mechanics, and other vital mechanics much in the same way as we now look on Vaucanson's duck.
Associated or even identical with this is the fact that in proportion as mechanical interpretation advances, the difficulties it has to surmount continually crop up anew. Processes which seem of the simplest kind and the most likely to be capable of purely mechanical explanation, processes such as those of assimilation, digestion, respiration, for which it was believed that exact parallels existed in the purely mechanical domain, as, for instance, in the osmotic processes of porous membranes, are seen when closely scrutinised as they occur in the living body to be extremely complex; in fact they have to be transferred“provisionally”from the mechanical to the vital rubric. To this category belong the whole modern development of the cell-theory, which replaces the previouslysinglemechanism in the living body by millions of them, every one of which raises as many problems as the one had done in the days of cruder interpretation. Every individual cell, as it appears to our understanding to-day, is at least as complicated a riddle as the whole organism formerly appeared.
But further: the modern development of biology has emphasised a special problem, which was first formulated[pg 231]by Leibnitz (though it is in antithesis to his fundamental Monad-theory), and which appears incapable of solution on mechanical lines. Leibnitz declared living beings to be“machines,”but machines of a peculiar kind. Even the most complicated machine, in the ordinary sense, consists of a combination of smaller“machines,”that is to say, of wheels, systems of levers, &c., of a simpler kind. And these sub-machines may in their turn consist of still simpler ones, and so on. But ultimately a stage is reached when the component parts are homogeneous, and cannot be analysed into simpler machines. It is otherwise with the organism. According to Leibnitz it consists of machines made up of other machines, and so on, into the infinitely little. However far we can proceed in our analysis of the parts, we shall still find that they are syntheses, made up of most ingeniously complex component parts, and this as far as our powers of seeing and distinguishing will carry us. That is to say: organisation is continued on into the infinitely little.
Leibnitz's illustration of the fish-pond is well known. He could have no better corroboration of his theory than the results of modern investigation afford. His doctrine of the continuation of organisation downwards into ever smaller expression is confirmed to a certain extent even by anatomy. By analysing structural organisation down to cells a definite point seemed to have been reached. But it now appears that at that point the problem is only beginning. One organisation is made[pg 232]up of other organisations—cells, protoplasm, nucleus, nucleolus, centrosomes, and so on, according to the power of the microscope; and these structures, instead of explaining the vital functions of growth, development, multiplication by division, and the rest, simply repeat them on a smaller scale, and are thus in their turn living units, the aggregation of which is illustrated better by the analogy of a social organism than by that of a mechanical structure.
In order to follow the mechanical explanation along the six lines we have previously indicated, we shall, as we have already said, entrust ourselves to the specialists who are on the opposite side. The difficulties and objections which the mechanical theory has to face have forced themselves insistently upon us even in the course of a short sketch such as has just been given, but they will be clearly realised if we approach them from the other side. But, first of all, a word as to the fundamental and, it is alleged, unassailable doctrine on which the theory as a whole is based, the“law of the conservation of energy.”The appeal to this, at any rate in the way in which it is usually made, is apt to be so distorted that the case must first be clearly stated before we can get further with the discussion.
The Law of the Conservation of Energy.Helmholtz's proof established mathematically what Kant had already, by direct insight, advanced as anà priorifundamental axiom: that in any given system[pg 233]the sum of energy can neither increase (impossibility of aperpetuum mobile) nor diminish (there is no disappearance of energy, but only transformation into another form). But even the vitalist had no need to deny this proposition. The“energy”which is required for the work of directing, setting agoing, changing and rearranging the chemico-physical processes in the body, and bringing about the effective reactions to stimuli which result in“development,”“transmission,”“regeneration,”and so on—if indeed any energy is required—of course could not come“from within”as a spontaneous increase of the existing sum of energy—that would, indeed, be a magical becoming out of nothing!—but must naturally be thought of as coming“from without.”The appeal to the law of the conservation of energy is therefore in itself irrelevant; but it conceals behind it an assertion of a totally different kind, namely, that in relation to physico-chemical sequences there can be no“without,”nothing transcending them—an assertion which Helmholtz's arguments cannot and were never intended to establish. But before any definite attitude to this newly imported assertion could be taken up, it would require to be distinctly defined, and that would lead us at once into all the depths of epistemological discussion. Here, therefore, we can only say so much: If this assertion is accepted it is well to see where it carries us; namely, back to the first-described naïve standpoint, which, without critical scruples, quite seriously accepts the world as it appears to it for the[pg 234]reality, and quite seriously speaks of an infinity lying in time behind us—and therefore come to an end—and is not in the least disturbed from its“dogmatic slumber”by this or any of the other great antinomies of our conception of the universe. And it remains, too, for this standpoint to come to terms with the fact that, in voluntary actions, of which we have the most direct knowledge, we have through our will the power of intervention in the physico-chemical nexus of our bodily energies—a fact which implies the existence of a“without,”from which interpolations or influences may flow into the physico-chemical system, even if there be none in regard to the domain of“vital”phenomena. And we should require to find out through what parallelistic or abruptly idealistic system the“without”was done away with in this case. For if a transcendental basis, or reverse side, or cause of things, be admitted—even if only in the form of our materialistic popular metaphysics (the“substance”of Haeckel's“world-riddle”)—then a“without,”from which primarily the cosmic system with its constant sum of matter and energy is explained, is also admitted, and it is difficult to see why it should have exhausted itself in this single effort.
Helmholtz's proof established mathematically what Kant had already, by direct insight, advanced as anà priorifundamental axiom: that in any given system[pg 233]the sum of energy can neither increase (impossibility of aperpetuum mobile) nor diminish (there is no disappearance of energy, but only transformation into another form). But even the vitalist had no need to deny this proposition. The“energy”which is required for the work of directing, setting agoing, changing and rearranging the chemico-physical processes in the body, and bringing about the effective reactions to stimuli which result in“development,”“transmission,”“regeneration,”and so on—if indeed any energy is required—of course could not come“from within”as a spontaneous increase of the existing sum of energy—that would, indeed, be a magical becoming out of nothing!—but must naturally be thought of as coming“from without.”The appeal to the law of the conservation of energy is therefore in itself irrelevant; but it conceals behind it an assertion of a totally different kind, namely, that in relation to physico-chemical sequences there can be no“without,”nothing transcending them—an assertion which Helmholtz's arguments cannot and were never intended to establish. But before any definite attitude to this newly imported assertion could be taken up, it would require to be distinctly defined, and that would lead us at once into all the depths of epistemological discussion. Here, therefore, we can only say so much: If this assertion is accepted it is well to see where it carries us; namely, back to the first-described naïve standpoint, which, without critical scruples, quite seriously accepts the world as it appears to it for the[pg 234]reality, and quite seriously speaks of an infinity lying in time behind us—and therefore come to an end—and is not in the least disturbed from its“dogmatic slumber”by this or any of the other great antinomies of our conception of the universe. And it remains, too, for this standpoint to come to terms with the fact that, in voluntary actions, of which we have the most direct knowledge, we have through our will the power of intervention in the physico-chemical nexus of our bodily energies—a fact which implies the existence of a“without,”from which interpolations or influences may flow into the physico-chemical system, even if there be none in regard to the domain of“vital”phenomena. And we should require to find out through what parallelistic or abruptly idealistic system the“without”was done away with in this case. For if a transcendental basis, or reverse side, or cause of things, be admitted—even if only in the form of our materialistic popular metaphysics (the“substance”of Haeckel's“world-riddle”)—then a“without,”from which primarily the cosmic system with its constant sum of matter and energy is explained, is also admitted, and it is difficult to see why it should have exhausted itself in this single effort.
Criticisms of the Mechanistic Theory of Life.The course of the mechanistic theory of life has been surprisingly similar to that of its complement, the theory of the general evolution of the organic world.[pg 235]The two great doctrines of the schools, Darwinism on the one hand, the mechanical interpretation of life on the other, are both tottering, not because of the criticism of outsiders, but of specialists within the schools themselves. And the interest which religion has in this is the same in both cases: the transcendental nature of things, the mysterious depth of appearance, which these theories denied or obscured, become again apparent. The incommensurableness and mystery of the world, which are, perhaps, even more necessary to the very life of religion than the right to regard it teleologically, reassert themselves afresh in the all-too-comprehensible and mathematically-formulated world, and re-establish themselves, notwithstanding obstinate and persistent attempts to do away with them. This is perhaps to the advantage of both natural science and religion: to the advantage of religion because it can with difficulty co-exist with the universal dominance of the mathematical way of looking at things; to the advantage of natural science because, in giving up the one-sidedness of the purely quantitative outlook, it does not give up its“foundations,”its“right to exist,”but only apetitio principiiand a prejudice that compelled it to exploit nature rather than to explain it, and to prescribe its ways rather than to seek them out.The reaction from the one-sided mechanical theories shows itself in many different ways and degrees. It may, according to the individual naturalist, affect the[pg 236]theory as a whole, or only certain parts of it, or only particular lines. It starts with mere criticism and with objections, which go no further than saying that“in the meantime”we are still far from having reached a physico-chemical solution of the riddle of life; it may ascend through all stages up to an absolute rejection of the theory as an idiosyncrasy of the time which impedes the progress of investigation, and as an uncritical prejudice of the schools. It may remain at the level of mere protest, and content itself with demonstrating the insufficiency of the mechanical explanation, without attempting to formulate any independent theory for the domain of the vital; or it may construct a specifically biological theory, claiming independence amid other disciplines, and basing this claim on the autonomy of vital processes; or it may widen out deliberately into metaphysical study and speculation. Taken at all these levels it presents such a complete section of the trend of modern ideas and problems that it would be an attractive study even apart from the special interest which attaches to it from the point of view of religious and idealistic conceptions of the universe.Both Liebig and Johannes Müller remained vitalists, notwithstanding the discovery of the synthesis of urea and the increasing number of organic compounds which were built up artificially by purely chemical methods. It was only about the middle of the last century that the younger generation, under the leadership, in Germany, of Du Bois-Reymond in particular, went over[pg 237]decidedly to the mechanistic side, and carried the doctrines of the school to ever fresh victories. But opposition was not lacking from the outset, though it was restrained and cautious.
The course of the mechanistic theory of life has been surprisingly similar to that of its complement, the theory of the general evolution of the organic world.[pg 235]The two great doctrines of the schools, Darwinism on the one hand, the mechanical interpretation of life on the other, are both tottering, not because of the criticism of outsiders, but of specialists within the schools themselves. And the interest which religion has in this is the same in both cases: the transcendental nature of things, the mysterious depth of appearance, which these theories denied or obscured, become again apparent. The incommensurableness and mystery of the world, which are, perhaps, even more necessary to the very life of religion than the right to regard it teleologically, reassert themselves afresh in the all-too-comprehensible and mathematically-formulated world, and re-establish themselves, notwithstanding obstinate and persistent attempts to do away with them. This is perhaps to the advantage of both natural science and religion: to the advantage of religion because it can with difficulty co-exist with the universal dominance of the mathematical way of looking at things; to the advantage of natural science because, in giving up the one-sidedness of the purely quantitative outlook, it does not give up its“foundations,”its“right to exist,”but only apetitio principiiand a prejudice that compelled it to exploit nature rather than to explain it, and to prescribe its ways rather than to seek them out.
The reaction from the one-sided mechanical theories shows itself in many different ways and degrees. It may, according to the individual naturalist, affect the[pg 236]theory as a whole, or only certain parts of it, or only particular lines. It starts with mere criticism and with objections, which go no further than saying that“in the meantime”we are still far from having reached a physico-chemical solution of the riddle of life; it may ascend through all stages up to an absolute rejection of the theory as an idiosyncrasy of the time which impedes the progress of investigation, and as an uncritical prejudice of the schools. It may remain at the level of mere protest, and content itself with demonstrating the insufficiency of the mechanical explanation, without attempting to formulate any independent theory for the domain of the vital; or it may construct a specifically biological theory, claiming independence amid other disciplines, and basing this claim on the autonomy of vital processes; or it may widen out deliberately into metaphysical study and speculation. Taken at all these levels it presents such a complete section of the trend of modern ideas and problems that it would be an attractive study even apart from the special interest which attaches to it from the point of view of religious and idealistic conceptions of the universe.
Both Liebig and Johannes Müller remained vitalists, notwithstanding the discovery of the synthesis of urea and the increasing number of organic compounds which were built up artificially by purely chemical methods. It was only about the middle of the last century that the younger generation, under the leadership, in Germany, of Du Bois-Reymond in particular, went over[pg 237]decidedly to the mechanistic side, and carried the doctrines of the school to ever fresh victories. But opposition was not lacking from the outset, though it was restrained and cautious.
Virchow's“Caution”.Here, as also in regard to“Darwinism,”which was advanced about the same time, the typical advocate of“caution”was Rudolf Virchow. His doubts and reservations found utterance very soon after the theory itself had been promulgated. In his“Cellular Pathologie,”76and in an essay on“The Old Vitalism and the New,”77he puts in a word for avis vitalis. The old vitalism, he declared, had been false because it assumed, not avis, but aspiritus vitalis. The substances in animate and in inanimate bodies have undoubtedly absolutely the same properties. Nevertheless,“we must at once rid ourselves of the scientific prudery of regarding the processes of life solely as the mechanical result of the molecular forces inherent in their constituent bodily parts.”The essential feature of life is a derived and communicated forceadditionalto the molecular forces. Whence it comes we are not told. He glided all round the problem with platitudinarian expressions, which were intended to show his own adherence as a matter of course to the new biological school, and which revealed at the same time his striking incapacity for defining a[pg 238]problem with any precision. At a“certain period in the evolution of the earth”this force arose, as the ordinary mechanical movements“swung over”into the vital. But it is thus a special form of movement, which detaches itself from the great constants of general movement, and runs its course alongside of, and in constant relation to, these. (Did ever vitalist assert more?) After thus preparing the way for a return of the veering process at a particular stage of evolution, and giving the necessary assurances against the“diametrically opposed dualistic position,”Virchow employs almost all the arguments against the mechanical theory which vitalists have ever brought forward. Even the catalytic properties of ferments are above the“ordinary”physical and chemical forces. The movement of crystallisation, too, cannot be compared with the vital movement. For vital force is not immanent in matter, but is always the product of previous life.78In the simplest processes of growth and nutrition thevis vitalisplays its vitalrôle. This is true in a much greater degree of the processes of development and morphogenesis. In the phenomena of irritability life reveals its spontaneity through“responses,”and so on.“Peu d'anatomie pathologique éloigne du vitalisme, beaucoup d'anatomie pathologique y ramène.”It is impossible to make much of this position. It leaves the theory with one of the opposing parties, the[pg 239]practice with the other, and the problem just where it was before.
Here, as also in regard to“Darwinism,”which was advanced about the same time, the typical advocate of“caution”was Rudolf Virchow. His doubts and reservations found utterance very soon after the theory itself had been promulgated. In his“Cellular Pathologie,”76and in an essay on“The Old Vitalism and the New,”77he puts in a word for avis vitalis. The old vitalism, he declared, had been false because it assumed, not avis, but aspiritus vitalis. The substances in animate and in inanimate bodies have undoubtedly absolutely the same properties. Nevertheless,“we must at once rid ourselves of the scientific prudery of regarding the processes of life solely as the mechanical result of the molecular forces inherent in their constituent bodily parts.”The essential feature of life is a derived and communicated forceadditionalto the molecular forces. Whence it comes we are not told. He glided all round the problem with platitudinarian expressions, which were intended to show his own adherence as a matter of course to the new biological school, and which revealed at the same time his striking incapacity for defining a[pg 238]problem with any precision. At a“certain period in the evolution of the earth”this force arose, as the ordinary mechanical movements“swung over”into the vital. But it is thus a special form of movement, which detaches itself from the great constants of general movement, and runs its course alongside of, and in constant relation to, these. (Did ever vitalist assert more?) After thus preparing the way for a return of the veering process at a particular stage of evolution, and giving the necessary assurances against the“diametrically opposed dualistic position,”Virchow employs almost all the arguments against the mechanical theory which vitalists have ever brought forward. Even the catalytic properties of ferments are above the“ordinary”physical and chemical forces. The movement of crystallisation, too, cannot be compared with the vital movement. For vital force is not immanent in matter, but is always the product of previous life.78In the simplest processes of growth and nutrition thevis vitalisplays its vitalrôle. This is true in a much greater degree of the processes of development and morphogenesis. In the phenomena of irritability life reveals its spontaneity through“responses,”and so on.“Peu d'anatomie pathologique éloigne du vitalisme, beaucoup d'anatomie pathologique y ramène.”
It is impossible to make much of this position. It leaves the theory with one of the opposing parties, the[pg 239]practice with the other, and the problem just where it was before.
Preyer's Position.Along with Virchow, we must name another of the older generation, the physiologist William Preyer, who combated“vitalism,”“dualism,”and“mechanism”with equal vehemence, and issued a manifesto, already somewhat solemn and official, against“vital force.”And yet he must undoubtedly be regarded as a vitalist by mechanists and vitalists alike.79He is more definite than Virchow, for he does not content himself with general statements as to the“origin”of vital force, and of the“swinging over”of the merely mechanical energies into the domain of the vital, but holds decidedly to the propositionomne vivum e vivo. He therefore maintains that life has always existed in the cosmos, and entirely rejects spontaneous generation.The fallacy, he says, of the mechanistic claims was due to the increasing number of physical explanations of isolated vital phenomena, and of imitations of the chemical products of organic metabolism. A wrong conclusion was drawn from these.“Any one who hopes to deduce from the chemical and physical properties of the fertilised egg the necessity that an animal, tormented by hunger and love must, after a[pg 240]certain time, arise therefrom, has a pathetic resemblance to the miserable manufacturers of homunculi.”Life is one of the underivable and inexplicable fundamental functions of universal being. From all eternity life has only been produced from life.As Preyer accepts the Kant-Laplace theory of the origin of our earth from the sun, he reaches ideas which have points of contact with the“cosmo-organic”ideas of Fechner. Life was present even when the earth was a fiery fluid sphere, and was possibly more general and more abundant then than it is now. And life as we know it may only be a smaller and isolated expression of that more general life.80[pg 241]Among the younger generation of specialists, those most often quoted as opponents of the mechanical theory are probably Bunge, Rindfleisch, Kerner von Marilaun, Neumeister and Wolff. A special group among them, not very easy to classify, may be called the Tectonists. Associated with them is Reinke's“Theory of Dominants.”Driesch started from their ranks, and is a most interesting example of consistent development from a recognition of the impossibilities of the mechanistic position to an individually thought-out vitalistic theory. Hertwig, too, takes a very definite position of his own in regard to these matters. Perhaps the most original contribution in the whole field is Albrecht's“Theory of Different Modes of Regarding Things.”We may close the list with the name of K. C. Schneider, who has carried these modern ideas on into metaphysical speculation. Several others might be mentioned along with and connecting these representative names.81
Along with Virchow, we must name another of the older generation, the physiologist William Preyer, who combated“vitalism,”“dualism,”and“mechanism”with equal vehemence, and issued a manifesto, already somewhat solemn and official, against“vital force.”And yet he must undoubtedly be regarded as a vitalist by mechanists and vitalists alike.79He is more definite than Virchow, for he does not content himself with general statements as to the“origin”of vital force, and of the“swinging over”of the merely mechanical energies into the domain of the vital, but holds decidedly to the propositionomne vivum e vivo. He therefore maintains that life has always existed in the cosmos, and entirely rejects spontaneous generation.
The fallacy, he says, of the mechanistic claims was due to the increasing number of physical explanations of isolated vital phenomena, and of imitations of the chemical products of organic metabolism. A wrong conclusion was drawn from these.“Any one who hopes to deduce from the chemical and physical properties of the fertilised egg the necessity that an animal, tormented by hunger and love must, after a[pg 240]certain time, arise therefrom, has a pathetic resemblance to the miserable manufacturers of homunculi.”Life is one of the underivable and inexplicable fundamental functions of universal being. From all eternity life has only been produced from life.
As Preyer accepts the Kant-Laplace theory of the origin of our earth from the sun, he reaches ideas which have points of contact with the“cosmo-organic”ideas of Fechner. Life was present even when the earth was a fiery fluid sphere, and was possibly more general and more abundant then than it is now. And life as we know it may only be a smaller and isolated expression of that more general life.80
Among the younger generation of specialists, those most often quoted as opponents of the mechanical theory are probably Bunge, Rindfleisch, Kerner von Marilaun, Neumeister and Wolff. A special group among them, not very easy to classify, may be called the Tectonists. Associated with them is Reinke's“Theory of Dominants.”Driesch started from their ranks, and is a most interesting example of consistent development from a recognition of the impossibilities of the mechanistic position to an individually thought-out vitalistic theory. Hertwig, too, takes a very definite position of his own in regard to these matters. Perhaps the most original contribution in the whole field is Albrecht's“Theory of Different Modes of Regarding Things.”We may close the list with the name of K. C. Schneider, who has carried these modern ideas on into metaphysical speculation. Several others might be mentioned along with and connecting these representative names.81
The Position Of Bunge and Other Physiologists.For a long time one of the most prominent figures in the controversy was Prof. G. Bunge, of Basle, who was one of the first modern physiologists to champion vitalism, and who has tried to show by analogies and illustrations what is necessarily implied in vital activity.82The mechanical reduction of vital phenomena to physico-chemical forces, he says, is impossible, and becomes more and more so as our knowledge deepens. He brings forward a series of convincing examples of the way in which apparent mechanical explanations have broken down. The absorption of the chyle through the walls of the intestine seemed to be a mechanically intelligible process[pg 243]of osmosis and diffusion. But in reality it proves to be rather a process of selection on the part of the epithelial cells of the intestine, analogous to the selection and rejection exercised elsewhere by unicellular organisms. In the same way the epithelial cells of the mammary glands“select”the suitable substances from the blood. It is impossible to explain in a mechanical way the power which directs the innumerable different chemical and physical processes within the organism, whether they be the bewilderingly purposeful reactions in the individual life of the cell, which seem to point to psychic processes within the plasm, or the riddles of development and of inheritance in particular; for how can a spermatozoon, so small that 500 millions can lie on a cubic line, be the bearer of all the peculiarities of the father to the son?In Lecture III. Bunge defines his attitude towards the law of the conservation of energy. In so doing he unconsciously follows the lines laid down by Descartes. All processes of movement and all functions exhibited by the living substance are the results of the accumulated potential energies, and the sums of work done and energy utilised remain the same. But the liberation and the direction of these energies is a factor by itself, which neither increases nor diminishes the sum of energies.“Occasiones”and“causæ”are brought into the field once more. The energies effect the phenomena, but they require“occasiones”to liberate them—thus a stone may fall to the ground by virtue of the[pg 244]potential energies stored in it at the time of its suspension, but it cannot fall until the thread by which it hangs has been cut. The function of the“occasio”itself is something quite outside of and without relation to the effect caused; it is a matter of indifference whether the thread be cut gently through with a razor or shot in two with a cannon ball.Kassowitz83is an instructive example of how much the force of criticism has been recognised even by those occupying a convinced mechanical point of view. He subjects all the different theories which attempt to explain the chief vital phenomena in mechanical terms to a long and exhaustive examination. The theories of the organism as a thermodynamic engine, osmotic theories, theories of ferments, interpretations in terms of electro-dynamics and molecular-physics—are all examined (chap. iv.); and the failure of all these hypotheses, notwithstanding the enormous amount of ingenuity expended in their construction, is summed up in an emphatic“Ignoramus.”“The failure is a striking one,”and it is frankly admitted that, in strong contrast to the earlier mood of confident hope, there now prevails a mood of resignation in regard to the mechanical-experimental investigation of the living organism, and that even specialists of the first rank are finding that they have to reckon again seriously with vital force. This breakdown and these admissions do not exactly tend to prejudice us in favour of the[pg 245]author's own attempt to substantiate new mechanical theories.In the comprehensive text-book of physiological chemistry by R. Neumeister, the mechanical standpoint seemed to be adhered to as the ideal. But the same writer forsakes it entirely, and disputes it energetically in his most recent work,“Betrachtungen über das Wesen der Lebenserscheinungen”84(“Considerations as to the Nature of Vital Phenomena”). He passes over all the larger problems, such as those of development, inheritance, regeneration, and confines himself in the main to the physiological functions of protoplasm, especially to those of the absorption of food and metabolism. And he shows, by means of illustrations, in part Bunge's, in part his own, and in close sympathy with Wundt's views, that even these vital phenomena cannot possibly be explained in terms of chemical affinity, physical osmosis, and the like. In processes of selection (such as, for instance, the excretion of urea and the retention of sugar in the blood), the“aim is obvious, but the causes cannot be recognised.”Psychical processes play a certain part in the functions of protoplasm in the form of qualitative and quantitative sensitiveness. All the mechanical processes in living organisms are initiated and directed by psychical processes. Physical, chemical and mechanical laws are perfectly valid, but they are not absolutely dominant. Living matter is to be defined as“a unique chemical[pg 246]system, the molecules of which, by their peculiar reciprocal action, give rise to psychical and material processes in such a way that the processes of the one kind are always causally conditioned and started by those of the other kind.”The psychical phenomena he regards as transcendental, supernatural,“mystical,”yet unquestionably also subject to a strict causal nexus, although the causality must remain for ever concealed. Starting from this basis, he analyses and rejects the explanations which have been offered in terms of the analogy of ferments, enzymes, or catalytic processes. In particular, he disputes Ostwald's“Energismus”and Verworn's Biogen hypothesis.85[pg 247]Among the vitalists of to-day, one of the most frequently cited, perhaps, except Driesch the most frequently cited, is G. Wolff, aPrivatdozent, formerly at Würzburg, now at Basle. He has only published short lectures and essays, and these deal not so much with the mechanical theory as with Darwinism.86But in these writings his main argument is that of his concluding chapter: the spontaneous adaptiveness of the organism, which nullifies all contingent theories to explain the purposiveness in ontogeny and phylogeny. And in his lecture,“Mechanismus und Vitalismus,”87in which he directs his attention especially to criticising Bütschli's defence of mechanism, the only problem to which prominence is given is the one with which we are here concerned. In spite of their brevity, these writings have given rise to much controversy, because what is peculiar to the two standpoints is described with precision, and the problem is clearly defined. His criticism had its starting-point in, and received a special impulse from an empirical proof, due to a very happy experiment of his own, of the marvellous regenerative capacity, and the inherent purposive[pg 248]activity of the living organism. He succeeded in proving that if the lens of the eye of the newt be excised, it may be regrown. The importance of this fact is greatly increased if we trace out in detail the various impossible rival mechanical interpretations which have grown up around this interesting case. As Driesch says,“It is not a restoration starting from the wound, it is a substitution starting from a different place.”
For a long time one of the most prominent figures in the controversy was Prof. G. Bunge, of Basle, who was one of the first modern physiologists to champion vitalism, and who has tried to show by analogies and illustrations what is necessarily implied in vital activity.82The mechanical reduction of vital phenomena to physico-chemical forces, he says, is impossible, and becomes more and more so as our knowledge deepens. He brings forward a series of convincing examples of the way in which apparent mechanical explanations have broken down. The absorption of the chyle through the walls of the intestine seemed to be a mechanically intelligible process[pg 243]of osmosis and diffusion. But in reality it proves to be rather a process of selection on the part of the epithelial cells of the intestine, analogous to the selection and rejection exercised elsewhere by unicellular organisms. In the same way the epithelial cells of the mammary glands“select”the suitable substances from the blood. It is impossible to explain in a mechanical way the power which directs the innumerable different chemical and physical processes within the organism, whether they be the bewilderingly purposeful reactions in the individual life of the cell, which seem to point to psychic processes within the plasm, or the riddles of development and of inheritance in particular; for how can a spermatozoon, so small that 500 millions can lie on a cubic line, be the bearer of all the peculiarities of the father to the son?
In Lecture III. Bunge defines his attitude towards the law of the conservation of energy. In so doing he unconsciously follows the lines laid down by Descartes. All processes of movement and all functions exhibited by the living substance are the results of the accumulated potential energies, and the sums of work done and energy utilised remain the same. But the liberation and the direction of these energies is a factor by itself, which neither increases nor diminishes the sum of energies.“Occasiones”and“causæ”are brought into the field once more. The energies effect the phenomena, but they require“occasiones”to liberate them—thus a stone may fall to the ground by virtue of the[pg 244]potential energies stored in it at the time of its suspension, but it cannot fall until the thread by which it hangs has been cut. The function of the“occasio”itself is something quite outside of and without relation to the effect caused; it is a matter of indifference whether the thread be cut gently through with a razor or shot in two with a cannon ball.
Kassowitz83is an instructive example of how much the force of criticism has been recognised even by those occupying a convinced mechanical point of view. He subjects all the different theories which attempt to explain the chief vital phenomena in mechanical terms to a long and exhaustive examination. The theories of the organism as a thermodynamic engine, osmotic theories, theories of ferments, interpretations in terms of electro-dynamics and molecular-physics—are all examined (chap. iv.); and the failure of all these hypotheses, notwithstanding the enormous amount of ingenuity expended in their construction, is summed up in an emphatic“Ignoramus.”“The failure is a striking one,”and it is frankly admitted that, in strong contrast to the earlier mood of confident hope, there now prevails a mood of resignation in regard to the mechanical-experimental investigation of the living organism, and that even specialists of the first rank are finding that they have to reckon again seriously with vital force. This breakdown and these admissions do not exactly tend to prejudice us in favour of the[pg 245]author's own attempt to substantiate new mechanical theories.
In the comprehensive text-book of physiological chemistry by R. Neumeister, the mechanical standpoint seemed to be adhered to as the ideal. But the same writer forsakes it entirely, and disputes it energetically in his most recent work,“Betrachtungen über das Wesen der Lebenserscheinungen”84(“Considerations as to the Nature of Vital Phenomena”). He passes over all the larger problems, such as those of development, inheritance, regeneration, and confines himself in the main to the physiological functions of protoplasm, especially to those of the absorption of food and metabolism. And he shows, by means of illustrations, in part Bunge's, in part his own, and in close sympathy with Wundt's views, that even these vital phenomena cannot possibly be explained in terms of chemical affinity, physical osmosis, and the like. In processes of selection (such as, for instance, the excretion of urea and the retention of sugar in the blood), the“aim is obvious, but the causes cannot be recognised.”Psychical processes play a certain part in the functions of protoplasm in the form of qualitative and quantitative sensitiveness. All the mechanical processes in living organisms are initiated and directed by psychical processes. Physical, chemical and mechanical laws are perfectly valid, but they are not absolutely dominant. Living matter is to be defined as“a unique chemical[pg 246]system, the molecules of which, by their peculiar reciprocal action, give rise to psychical and material processes in such a way that the processes of the one kind are always causally conditioned and started by those of the other kind.”The psychical phenomena he regards as transcendental, supernatural,“mystical,”yet unquestionably also subject to a strict causal nexus, although the causality must remain for ever concealed. Starting from this basis, he analyses and rejects the explanations which have been offered in terms of the analogy of ferments, enzymes, or catalytic processes. In particular, he disputes Ostwald's“Energismus”and Verworn's Biogen hypothesis.85
Among the vitalists of to-day, one of the most frequently cited, perhaps, except Driesch the most frequently cited, is G. Wolff, aPrivatdozent, formerly at Würzburg, now at Basle. He has only published short lectures and essays, and these deal not so much with the mechanical theory as with Darwinism.86But in these writings his main argument is that of his concluding chapter: the spontaneous adaptiveness of the organism, which nullifies all contingent theories to explain the purposiveness in ontogeny and phylogeny. And in his lecture,“Mechanismus und Vitalismus,”87in which he directs his attention especially to criticising Bütschli's defence of mechanism, the only problem to which prominence is given is the one with which we are here concerned. In spite of their brevity, these writings have given rise to much controversy, because what is peculiar to the two standpoints is described with precision, and the problem is clearly defined. His criticism had its starting-point in, and received a special impulse from an empirical proof, due to a very happy experiment of his own, of the marvellous regenerative capacity, and the inherent purposive[pg 248]activity of the living organism. He succeeded in proving that if the lens of the eye of the newt be excised, it may be regrown. The importance of this fact is greatly increased if we trace out in detail the various impossible rival mechanical interpretations which have grown up around this interesting case. As Driesch says,“It is not a restoration starting from the wound, it is a substitution starting from a different place.”