It is well for the reputation of Aristotle that he could apply himself with such devotion to the arduous and, in his time, inglorious researches of natural history and comparative anatomy, since it was only in those departments that he made any real contributions to physical science. In the studies which were to him the noblest and most entrancing of any, his speculations are one long record of wearisome, hopeless, unqualified delusion. If, in the philosophy of practice and the philosophy of art, he afforded no real guidance at all, in the philosophy of Nature his guidance hasalways led men fatally astray. So far as his means of observation extended, there was nothing that he did not attempt to explain, and in every single instance he was wrong. He has written about the general laws of matter and motion, astronomy, chemistry, meteorology, and physiology, with the result that he has probably made more blunders on those subjects than any human being ever made before or after him. And, if there is one thing more astounding than his unbroken infelicity of speculation, it is the imperturbable self-confidence with which he puts forward his fallacies as demonstrated scientific certainties. Had he been right, it was no ‘slight or partial glimpses of the beloved’ that would have been vouchsafed him, but the ‘fullest and nearest revelation’ of her beauties. But the more he looked the less he saw. Instead of drawing aside he only thickened and darkened the veils of sense which obscured her, by mistaking them for the glorious forms that lay concealed beneath.
Modern admirers of Aristotle labour to prove that his errors were inevitable, and belonged more to his age than to himself; that without the mechanical appliances of modern times science could not be cultivated with any hope of success. But what are we to say when we find that on one point after another the true explanation had already been surmised by Aristotle’s predecessors or contemporaries, only to be scornfully rejected by Aristotle himself? Their hypotheses may often have been very imperfect, and supported by insufficient evidence; but it must have been something more than chance which always led him wrong when they were so often right. To begin with, the infinity of space is not even now, nor will it ever be, established by improved instruments of observation and measurement; it is deduced by a very simple process of reasoning, of which Democritus and others were capable, while Aristotle apparently was not. He rejects the idea because it is inconsistent with certain very arbitrary assumptions and definitions of his own, whereas he should haverejected them because they were inconsistent with it. He further rejects the idea of a vacuum, and with it the atomic theory, entirely onà priorigrounds, although, even in the then existing state of knowledge, atomism explained various phenomena in a perfectly rational manner which he could only explain by unmeaning or nonsensical phrases.195It had been already maintained, in his time, that the apparent movements of the heavenly bodies were due to the rotation of the earth on its own axis.196Had Aristotle accepted this theory one can imagine how highly his sagacity would have been extolled. We may, therefore, fairly take his rejection of it as a proof of blind adherence to old-fashioned opinions. When he argues that none of the heavenly bodies rotate, because we can see that the moon does not, as is evident from her always turning the same side to us,197nothing is needed but the simplest mathematics to demonstrate the fallacy of his reasoning. Others had surmised that the Milky Way was a collection of stars, and that comets were bodies of the same nature as planets. Aristotle is satisfied that both are appearances like meteors, and the aurora borealis—caused by the friction of our atmosphere against the solid aether above it. A similar origin is ascribed to the heat and light derived from the sun and stars; for it would be derogatory to the dignity of those luminaries to suppose, with Anaxagoras, that they are formed of anything so familiar and perishable as fire. On the contrary, they consist of pure aether like the spheres on which they are fixed as protuberances; thoughhow such an arrangement can co-exist with absolute contact between each sphere and that next below it, or how the effects of friction could be transmitted through such enormous thicknesses of solid crystal, is left unexplained.198By a happy anticipation of Roemer, Empedocles conjectured that the transmission of light occupied a certain time: Aristotle declares it to be instantaneous.199
On passing to terrestrial physics, we find that Aristotle is, as usual, the dupe of superficial appearances, against which other thinkers were on their guard. Seeing that fire always moved up, he assumed that it did so by virtue of a natural tendency towards the circumference of the universe, as opposed to earth, which always moved towards the centre. The atomists erroneously held that all matter gravitated downwards through infinite space, but correctly explained the ascent of heated particles by the pressure of surrounding matter, in accordance, most probably, with the analogy of floating bodies.200Chemistry as a science is, of course, an entirely modern creation, but the first approach to it was made by Democritus, while no ancient philosopher stood farther from its essential principles than Aristotle. He analyses bodies, not into their material elements, but into the sensuous qualities, hot and cold, wet and dry, between which he supposes the underlying substance to be perpetually oscillating; a theory which, if it were true, would make any fixed laws of nature impossible.
It might have been expected that, on reaching physiology, the Stagirite would stand on firmer ground than any of his contemporaries. Such, however, is not the case. As already observed, his achievements belong entirely to the dominion of anatomy and descriptive zoology. The whole internal economy of the animal body is, according to him, designed for the purpose of creating and moderating the vital heat;and in apportioning their functions to the different organs he is entirely dominated by this fundamental error. It was a common notion among the Greeks, suggested by sufficiently obvious considerations, that the brain is the seat of the psychic activities. These, however, Aristotle transports to the heart, which, in his system, not only propels the blood through the body, but is also the source of heat, the common centre where the different special sensations meet to be compared, and the organ of imagination and of passion. The sole function of the brain is to cool down the blood—a purpose which the lungs also subserve. Some persons believe that air is a kind of food, and is inhaled in order to feed the internal fire; but their theory would involve the absurd consequence that all animals breathe, for all have some heat. Anaxagoras and Diogenes did, indeed, make that assertion, and the latter even went so far as to say that fish breathe with their gills, absorbing the air held in solution by the water passed through them—a misapprehension, says Aristotle, which arose from not having studied the final cause of respiration.201His physiological theory of generation is equally unfortunate. In accordance with his metaphysical system, hereafter to be explained, he distinguishes two elements in the reproductive process, of which one, that contributed by the male, is exclusively formative; and the other, that contributed by the female, exclusively material. The prevalent opinion was evidently, what we know now to be true, that each parent has both a formative and a material share in the composition of the embryo. Again, Aristotle, strangely enough, regards the generative element in both sexes as an unappropriated portion of the animal’s nutriment, the last and most refined product of digestion, and therefore not a portion of the parental system at all; while other biologists, anticipating Mr. Darwin’s theory of pangenesis in a very wonderful manner, taught that the semen is a conflux of molecules derived from every part of the body, and thus strove to account for the hereditary transmission of individual peculiarities to offspring.202
All these, however, are mere questions of detail. It is on a subject of the profoundest philosophical importance that Aristotle differs most consciously, most radically, and most fatally from his predecessors. They were evolutionists, and he was a stationarist. They were mechanicists, and he was a teleologist. They were uniformitarians, and he was a dualist. It is true that, as we mentioned at the beginning of this chapter, Mr. Edwin Wallace makes him ‘recognise the genesis of things by evolution and development,’ but the meaning of this phrase requires to be cleared up. In one sense it is, of course, almost an identical proposition. The genesis of things must be by genesis of some kind or other. The great question is, what things have been evolved, and how have they been evolved? Modern science tells us, that not only have all particular aggregates of matter and motion now existing come into being within a finite period of time, but also that the specific types under which we arrange those aggregates have equally been generated; and that their characteristics, whether structural or functional, can only be understood by tracing out their origin and history. And it further teaches us that the properties of every aggregate result from the properties of its ultimate elements, which, within the limits of our experience, remain absolutely unchanged. Now, Aristotle taught very nearly the contrary of all this. He believed that the cosmos, as we now know it, had existed, and would continue to exist, unchanged through all eternity. The sun, moon, planets, and stars, together with the orbs containing them, are composed of an absolutely ungenerable, incorruptible substance. The earth, a cold, heavy, solid sphere, though liable to superficial changes, has always occupied its present position in the centre of the universe.The specific forms of animal life—except a few which are produced spontaneously—have, in like manner, been preserved unaltered through an infinite series of generations. Man shares the common lot. There is no continuous progress of civilisation. Every invention and discovery has been made and lost an infinite number of times. Our philosopher could not, of course, deny that individual living things come into existence and gradually grow to maturity; but he insists that their formation is teleologically determined by the parental type which they are striving to realise. He asks whether we should study a thing by examining how it grows, or by examining its completed form: and Mr. Wallace quotes the question without quoting the answer.203Aristotle tells us that the genetic method was followed by his predecessors, but that the other method is his. And he goes on to censure Empedocles for saying that many things in the animal body are due simply to mechanical causation; for example, the segmented structure of the backbone, which that philosopher attributes to continued doubling and twisting—the very same explanation, we believe, that would be given of it by a modern evolutionist.204Finally, Aristotle assumes the only sort of transformation which we deny, and which Democritus equally denied—that is to say, the transformation of the ultimate elements into one another by the oscillation of an indeterminate matter between opposite qualities.
The truth is that while our philosopher had one of the most powerful intellects ever possessed by any man, it was an intellect strictly limited to the surface of things. He was utterly incapable of divining the hidden forces by which inorganic nature and life and human society are moved. He had neither the genius which can reconstruct the past, nor the genius which partly moulds, partly foretells the future. But wherever he has to observe or to report, to enumerate or to analyse, to describe or to define, to classify or to compare; and whatever be the subject, a mollusc or a mammal, a mouse or an elephant; the structure and habits of wild animals; the different stages in the development of an embryo bird; the variations of a single organ or function through the entire zoological series; the hierarchy of intellectual faculties; the laws of mental association; the specific types of virtuous character; the relation of equity to law; the relation of reason to impulse; the ideals of friendship; the different members of a household; the different orders in a State; the possible variations of political constitutions, or within the same constitution; the elements of dramatic or epic poetry; the modes of predication; the principles of definition, classification, judgment, and reasoning; the different systems of philosophy; all varieties of passion, all motives to action, all sources of conviction;—there we find an enormous accumulation of knowledge, an unwearied patience of research, a sweep of comprehension, a subtlety of discrimination, an accuracy of statement, an impartiality of decision, and an all-absorbing enthusiasm for science, which, if they do not raise him to the supreme level of creative genius, entitle him to rank a very little way below it.
It was natural that one who ranged with such consummate mastery over the whole world of apparent reality, should believe in no other reality; that for him truth should onlymean the systematisation of sense and language, of opinion, and of thought. The visible order of nature was present to his imagination in such precise determination and fulness of detail that it resisted any attempt he might have made to conceive it under a different form. Each of his conclusions was supported by analogies from every other department of enquiry, because he carried the peculiar limitations of his thinking faculty with him wherever he turned, and unconsciously accommodated every subject to the framework which they imposed. The clearness of his ideas necessitated the use of sharply-drawn distinctions, which prevented the free play of generalisation and fruitful interchange of principles between the different sciences. And we shall have occasion to show hereafter, that, when he attempted to combine rival theories, it was done by placing them in juxtaposition rather than by mutual interpenetration. Again, with his vivid perceptions, it was impossible for him to believe in the justification of any method claiming to supersede, or even to supplement, their authority. Hence he was hardly less opposed to the atomism of Democritus than to the scepticism of Protagoras or the idealism of Plato. Hence, also, his dislike for all explanations which assumed that there were hidden processes at work below the surface of things, even taking surface in its most literal sense. Thus, in discussing the question why the sea is salt, he will not accept the theory that rivers dissolve out the salt from the strata through which they pass, and carry it down to the sea, because river-water tastes fresh; and propounds in its stead the utterly false hypothesis of a dry saline evaporation from the earth’s surface, which he supposes to be swept seawards by the wind.205Even in his own especial province of natural history the same tendency leads him astray. He asserts that the spider throws off its web from the surface of its body like a skin, instead of evolving it from within, as Democritus had taught.206The same thinker hadendeavoured to prove by analogical reasoning that the invertebrate animals must have viscera, and that only their extreme minuteness prevents us from perceiving them; a view which his successor will not admit.207In fact, wherever the line between the visible and the invisible is crossed, Aristotle’s powers are suddenly paralysed, as if by enchantment.
Another circumstance which led Aristotle to disregard the happy aperçus of earlier philosophers was his vast superiority to them in positive knowledge. It never occurred to him that their sagacity might be greater than his, precisely because its exercise was less impeded by the labour of acquiring and retaining such immense masses of irrelevant facts. And his confidence was still further enhanced by the conviction that all previous systems were absorbed into his own, their scattered truths co-ordinated, their aberrations corrected, and their discords reconciled. But in striking a general average of existing philosophies, he was in reality bringing them back to that anonymous philosophy which is embodied in common language and common opinion. And if he afterwards ruled the minds of men with a more despotic sway than any other intellectual master, it was because he gave an organised expression to the principle of authority, which, if it could, would stereotype and perpetuate the existing type of civilisation for all time.
Here, then, are three main points of distinction between our philosopher and his precursors, the advantage being, so far, entirely on their side. He did not, like the Ionian physiologists, anticipate in outline our theories of evolution. He held that the cosmos had always been, by the strictest necessity, arranged in the same manner; the starry revolutions never changing; the four elements preserving a constant balance; the earth always solid; land and water always distributed according to their present proportions; livingspecies transmitting the same unalterable type through an infinite series of generations; the human race enjoying an eternal duration, but from time to time losing all its conquests in some great physical catastrophe, and obliged to begin over again with the depressing consciousness that nothing could be devised which had not been thought of an infinite number of times already; the existing distinctions between Hellenes and barbarians, masters and slaves, men and women, grounded on everlasting necessities of nature. He did not, like Democritus, distinguish between objective and subjective properties of matter; nor admit that void space extends to infinity round the starry sphere, and honeycombs the objects which seem most incompressible and continuous to our senses. He did not hope, like Socrates, for the regeneration of the individual, nor, like Plato, for the regeneration of the race, by enlightened thought. It seemed as if Philosophy, abdicating her high function, and obstructing the paths which she had first opened, were now content to systematise the forces of prejudice, blindness, immobility, and despair.
For the restrictions under which Aristotle thought were not determined by his personality alone; they followed on the logical development of speculation, and would have imposed themselves on any other thinker equally capable of carrying that development to its predetermined goal. The Ionian search for a primary cause and substance of nature led to the distinction, made almost simultaneously, although from opposite points of view, by Parmenides and Heracleitus, between appearance and reality. From that distinction sprang the idea of mind, organised by Socrates into a systematic study of ethics and dialectics. Time and space, the necessary conditions of physical causality, were eliminated from a method having for its form the eternal relations of difference and resemblance, for its matter the present interests of humanity. Socrates taught that before enquiring whence things come we must first determine what it is they are.Hence he reduced science to the framing of exact definitions. Plato followed on the same track, and refused to answer a single question about anything until the subject of investigation had been clearly determined. But the form of causation had taken such a powerful hold on Greek thought, that it could not be immediately shaken off; and Plato, as he devoted more and more attention to the material universe, saw himself compelled, like the older philosophers, to explain its construction by tracing out the history of its growth. What is even more significant, he applied the same method to ethics and politics, finding it easier to describe how the various virtues and types of social union came into existence, than to analyse and classify them as fixed ideas without reference to time. Again, while taking up the Eleatic antithesis of reality and appearance, and re-interpreting it as a distinction between noumena and phenomena, ideas and sensations, spirit and matter, he was impelled by the necessity of explaining himself, and by the actual limitations of experience to assimilate the two opposing series, or, at least, to view the fleeting, superficial images as a reflection and adumbration of the being which they concealed. And of all material objects, it seemed as if the heavenly bodies, with their orderly, unchanging movements, their clear brilliant light, and their remoteness from earthly impurities, best represented the philosopher’s ideal. Thus, Plato, while on the one side he reaches back to the pre-Socratic age, on the other reaches forward to the Aristotelian system.
Nor was this all. As the world of sense was coming back into favour, the world of reason was falling into disrepute. Just as the old physical philosophy had been decomposed by the Sophisticism of Protagoras and Gorgias, so also the dialectic of Socrates was corrupted into the sophistry of Eubulides and Euthydêmus. Plato himself discovered that by reasoning deductively from purely abstract premises, contradictory conclusions could be established with apparentlyequal force. It was difficult to see how a decision could be arrived at except by appealing to the testimony of sense. And a moral reform could hardly be effected except by similarly taking into account the existing beliefs and customs of mankind.
It is possible, we think, to trace a similar evolution in the history of the Attic drama. The tragedies of Aeschylus resemble the old Ionian philosophy in this, that they are filled with material imagery, and that they deal with remote interests, remote times, and remote places. Sophocles withdraws his action into the subjective sphere, and simultaneously works out a pervading contrast between the illusions by which men are either lulled to false security or racked with needless anguish, and the terrible or consolatory reality to which they finally awaken. We have also, in his well-known irony, in the unconscious self-betrayal of his characters, that subtle evanescent allusiveness to a hidden truth, that gleaming of reality through appearance which constitutes, first the dialectic, then the mythical illustration, and finally the physics of Plato. In Aeschylus also we have the spectacle of sudden and violent vicissitudes, the abasement of insolent prosperity, and the punishment of long successful crime; only with him the characters which attract most interest are not the blind victims, but the accomplices or the confidants of destiny—the great figures of a Prometheus, a Darius, an Eteocles, a Clytemnestra, and a Cassandra, who are raised above the common level to an eminence where the secrets of past and future are unfolded to their gaze. Far otherwise with Sophocles. The leading actors in his most characteristic works, Oedipus, Electra, Dejanira, Ajax, and Philoctetes, are surrounded by forces which they can neither control nor understand; moving in a world of illusion, if they help to work out their own destinies it is unconsciously, or even in direct opposition to their own designs.208Hence in Aeschylus we have somethinglike that superb self-confidence which distinguishes a Parmenides and a Heracleitus; in Sophocles that confession of human ignorance which the Athenian philosophers made on their own behalf, or strove to extract from others. Euripides introduces us to another mode of thought, more akin to that which characterises Aristotle. For, although there is abundance of mystery in his tragedies, it has not the profound religious significance of the Sophoclean irony; he uses it rather for romantic and sentimental purposes, for the construction of an intricate plot, or for the creation of pathetic situations. His whole power is thrown into the immediate and detailed representation of living passion, and of the surroundings in which it is displayed, without going far back into its historical antecedents like Aeschylus, or, like Sophocles, into the divine purposes which underlie it. On the other hand, as a Greek writer could not be other than philosophical, he uses particular incidents as an occasion for wide generalisations and dialectical discussions; these, and not the idea of justice or of destiny, being the pedestal on which his figures are set. And it may be noticed as another curious coincidence that, like Aristotle again, he is disposed to criticise his predecessors, or at least one of them, Aeschylus, with some degree of asperity.
The critical tendency just alluded to suggests one more reason why philosophy, from having been a method of discovery, should at last become a mere method of description and arrangement. The materials accumulated by nearly three centuries of observation and reasoning were so enormous that they began to stifle the imaginative faculty. If there was any opening for originality it lay in the task of carrying order into this chaos by reducing it to a few general heads, by mapping out the whole field of knowledge, and subjecting each particular branch to the new-found processes of definitionand classification. And along with the incapacity for framing new theories there arose a desire to diminish the number of those already existing, to frame, if possible, a system which should select and combine whatever was good in any or all of them.
This, then, was the revolution effected by Aristotle, that he found Greek thought in the form of a solid, and unrolled into a surface of the utmost possible tenuity, transparency, and extension. In so doing, he completed what Socrates and Plato had begun, he paralleled the course already described by Greek poetry, and he offered the first example of what since then has more than once recurred in the history of philosophy. It was thus that the residual substance of Locke and Berkeley was resolved into phenomenal succession by Hume. It was thus that the unexplained reality of Kant and Fichte was drawn out into a play of logical relations by Hegel. And, if we may venture on a forecast of the future towards which speculation is now advancing, it is thus that the limits imposed on human knowledge by positivists and agnostics in our own day, are yielding to the criticism of those who wish to establish either a perfect identity or a perfect equation between consciousness and being. This is the position represented in France by M. Taine, a thinker offering many points of resemblance to Aristotle, which it would be interesting to work out had we space at our command for the purpose. The forces which are now guiding English philosophy in an analogous direction have hitherto escaped observation on account of their disunion among themselves, and their intermixture with others of a different character. But on the whole we may say that the philosophy of Mill and his school corresponds very nearly in its practical idealism to Plato’s teaching; that Mr. Herbert Spencer approachesAristotle on the side of theorising systematisation, while sharing to a more limited extent the metaphysical and political realism which accompanied it: that Lewes was carrying the same transformation a step further in his unfinishedProblems of Life and Mind; that the philosophy of Mr. Shadworth Hodgson is marked by the same spirit of actuality, though not without a vista of multitudinous possibilities in the background; that the Neo-Hegelian school are trying to do over again for us what their master did in Germany; and that the lamented Professor Clifford had already given promise of one more great attempt to widen the area of our possible experience into co-extension with the whole domain of Nature.209
The systematising power of Aristotle, his faculty for bringing the isolated parts of a surface into co-ordination and continuity, is apparent even in those sciences with whose material truths he was utterly unacquainted. Apart from the falseness of their fundamental assumptions, his scientific treatises are, for their time, masterpieces of method. In this respect they far surpass his moral and metaphysical works, and they are also written in a much more vigorous style, occasionally even rising into eloquence. He evidently moves with much more assurance on the solid ground of external nature than in the cloudland of Platonic dialectics, or among the possibilities of an ideal morality. If, for example, we open hisPhysics, we shall find such notions as Causation, Infinity, Matter, Space, Time, Motion, and Force, for the first time in history separately discussed, defined, and made the foundation of natural philosophy. The treatiseOn the Heavensvery properly regards the celestial movements as a purely mechanical problem, and strives throughout to bring theory and practiceinto complete agreement. While directly contradicting the truths of modern astronomy, it stands on the same ground with them; and anyone who had mastered it would be far better prepared to receive those truths than if he were only acquainted with such a work as Plato’sTimaeus. The remaining portions of Aristotle’s scientific encyclopaedia follow in perfect logical order, and correspond very nearly to Auguste Comte’s classification, if, indeed, they did not directly or indirectly suggest it. We cannot, however, view the labours of Aristotle with unmixed satisfaction until he comes on to deal with the provinces of natural history, comparative anatomy, and comparative psychology. Here, as we have shown, the subject exactly suited the comprehensive observation and systematising formalism in which he excelled. Here, accordingly, not only the method but the matter of his teaching is good. In theorising about the causes of phenomena he was behind the best science of his age; in dissecting the phenomena themselves he was far before it. Of course very much of what he tells was learned at second-hand, and some of it is not authentic. But to collect such masses of information from the reports of uneducated hunters, fishermen, grooms, shepherds, beemasters, and the like, required an extraordinary power of putting pertinent questions, such as could only be acquired in the school of Socratic dialectic. Nor should we omit to notice the vivid intelligence which enabled even ordinary Greeks to supply him with the facts required for his generalisations. But some of his most important researches must be entirely original. For instance, he must have traced the development of the embryo chicken with his own eyes; and, here, we have it on good authority that his observations are remarkable for their accuracy, in a field where accuracy, according to Caspar Friedrich Wolff, is almost impossible.210
Still more important than these observations themselves is the great truth he derives from them—since rediscovered and worked out in detail by Von Baer—that in the development of each individual the generic characters make their appearance before the specific characters.211Nor is this a mere accidental or isolated remark, but, as we shall show in the next chapter, intimately connected with one of the philosopher’s metaphysical theories. Although not an evolutionist, he has made other contributions to biology, the importance of which has been first realised in the light of the evolution theory. Thus he notices the antagonism between individuation and reproduction;212the connexion of increased size with increased vitality;213the connexion of greater mobility,214and of greater intelligence,215with increased complexity of structure; the physiological division of labour in the higher animals;216the formation of heterogeneous organs out of homogeneous tissues;217the tendency towards greater centralisation in the higher organisms218—a remark connected with his two great anatomical discoveries, the central position of the heart in the vascular system, and the possession of a backbone by all red-blooded animals;219the resemblance of animal intelligence to a rudimentary human intelligence, especially as manifested in children;220and, finally, he attempts to trace a continuous series of gradations connecting the inorganic with the organic world, plants with animals, and the lower animals with man.221
The last mentioned principle gives one more illustration of the distinction between Aristotle’s system and that of the evolutionist, properly so called. The continuity recognisedby the former only obtains among a number of coexisting types; it is a purely logical or ideal arrangement, facilitating the acquisition and retention of knowledge, but adding nothing to its real content. The continuity of the latter implies a causal connexion between successive types evolved from each other by the action of mechanical forces. Moreover, our modern theory, while accounting for whatever is true in Aristotle’s conception, serves, at the same time, to correct its exaggeration. The totality of existing species only imperfectly fill up the interval between the highest human life and the inorganic matter from which we assume it to be derived, because they are collaterally, and not lineally, related. Probably no one of them corresponds to any less developed stage of another, although some have preserved, with more constancy than others, the features of a common parent. In diverging from a single stock (if we accept the monogenetic hypothesis,) they have become separated by considerable spaces, which the innumerable multitude of extinct species alone could fill up.
Our preliminary survey of the subject is now completed. So far, we have been engaged in studying the mind of Aristotle rather than his system of philosophy. In the next chapter we shall attempt to give a more complete account of that system in its internal organisation not less than in its relations to modern science and modern thought.