The pragmatist doctrine and attitude will perhaps be easier to understand if we take it in regard to a particular instance of truth and error in regard to fundamental notions. In the last four or five years a new principle has been formulated in Physics, named the Principle of Relativity. It revolutionises the current conceptions of space and time. It is so recent that probably some of my readers now hear of it for the first time, and therefore before I refer to its formulation by mathematicians I will give a simple illustration to explain what it is. Suppose that you are walking up and down the deck of a steamer, and let us suppose that the steamer is proceeding at the speed of four miles an hour, the space that you cover and the interval of time that you occupy are exactly the same for you whether you are moving up the deck in the direction the steamer is going or down the deck in the direction which is the reverse of the steamer's movement. But suppose some one on the shore could observe you moving while the ship was invisible to him, your movement would appear to him entirely different to what it is to you. When you were walking up the deck you would seem to be going at twice the speed you would be going, and when you were going down the deck you would seem not to be moving at all. The time measurement would also seem different to the observer on the shore, for while to you each moment would be measured by an equalspace covered, to him one moment you would be moving rapidly, the next at rest. This is simple and easy to understand. Now suppose that both you and the observer were each observing a natural phenomenon, say a thunder-storm, it would seem that each of you ought to observe it with a difference—a difference strictly calculable from the system of movement, the ship, in which you were placed in relation to him. The propagation of the sound and of the light would have to undergo a correction if each of you described your experience to the other. If you were moving in the direction of the light waves they would be slower for you than for him, and if against their direction they would be faster for you than for him. Of course the immense velocity of the light waves, about 200,000 miles a second, would make the difference in a movement of four miles an hour so infinitesimal as to be altogether inappreciable, but it would not be nothing, and you would feel quite confident that if it could be measured the infinitesimal quantity would appear in the result. Now suppose that we could measure it with absolute accuracy, and that the result was the discovery that the supposed difference did not exist at all—and of course, we suppose that there is no doubt whatever about the measurement—what, then, should we be obliged to think? We should be forced to believe that as the velocity of light was the same for the two observers, one moving, one at rest, therefore the space and the time must be different for each. Now, however strange it may seem, such a measurement has been made, and with this surprising result. In consequence there has been formulated a new principle in Physics named the Principle of Relativity. I take this Principle of Relativity for my illustration because it is based on reasoning that practically admits of no doubt, and becauseit requires us to form new conceptions of space and time which seem to alter fundamentally what we have hitherto considered as the evident and unmistakable nature of those realities. It has always seemed that the distance separating two points, and the interval of time separating two events, were each independent of the other and each absolute. However different the distance and the interval may appear to observers in movement or to observers in different systems of movement in relation to ourselves and to one another, in themselves they are the same distance and the same interval for all. They are the same for the man in the express train as for the man standing on the station platform. The Principle of Relativity requires us to think that this is not so, but that, contrary to all our settled notions, the actual space and time vary—really undergo an alteration, a contraction or expansion—with each different system of movement of translation to which the observer is bound. Events that for an observer belonging to one system of movement happen in the same place, for another observer in a different system of movement happen in different places. Events that for one observer happen simultaneously, for other observers are separated by a time interval according to the movement of translation of the system to which they belong. So that space, which Newton described as rigid, and time which he described as flowing at a constant rate, and which for him was absolute, are for the new theory relative, different for an observer in every different system of movement of translation. Or we may state it in the opposite way, and say that the Principle of Relativity shows us that the reason why natural phenomena, such as the rate of propagation of light, undergo no alteration when we pass from one system of movement of translation to another, as weare constantly doing in the changing velocity of the earth's movement round the sun, is that space and time alter with the velocity. I cannot here give the argument or describe the experiments which have given this result—I am simply taking it as an illustration.[1] It seems to me admirably suited to compare the pragmatist method and the pragmatist attitude with that of scientific realism and of absolute idealism.
[1] The Principle of Relativity is mainly the result of the recent mathematical work of H. A. Lorentz, Einstein, and the late Professor Minkowski. A very interesting and not excessively difficult, account of it is contained inDernières Pensées, by the late Henri Poincaré; Paris, Alcan.
Here, then, is a question in which the truth of our accepted notions is called in question, and new notions claim to be true. The sole question involved, pragmatism insists, is the truth of conceptions, not the reality of things, and there is but one way of testing the truth of conceptions—and that is by comparing the rival conceptions in respect of the practical consequences that follow from them and adopting those that will work. If the old conceptions of space and time fail to conform to a new need, then what was true before the need was revealed is no longer true, the new conception has become true. By verifying the new conception, we make it true. But, objects the realist, an idea cannot become true; what is now true always was true, and what is no longer true never was true, though we may have worked with the false notion ignorant that it was false. Behind truth there is reality. The earth was spherical even when all mankind believed it flat and found the belief work. To this the pragmatist reply is that reality is only our objectification of truth; it possesses no meaning divorced from human purposes. Had anyone announced that the earth was a spherewhen it was generally held to be flat, unless his announcement had some relevance to a defect in the flat earth notion, or a claim to revise that notion, his announcement would have been neither a truth nor a falsehood in any intelligible meaning of the term—he would have been making an irrelevant remark. The notions of space and time that Newton held worked, and were therefore true; if a new need requires us to replace them with other notions, and these other notions will work and are therefore true, they have become true and Newton's notions have become false. If it is still objected that the new notions were also true for Newton, although he was ignorant of them, the need for them not having arisen, the only reply is that truth, or reality, in complete detachment from human purposes, cannot be either affirmed or denied.
With this view the idealist will be in agreement; his objection is of a different kind. He rejects, as the pragmatist does, the notion of a reality independent of human nature that forces upon us the changes that our conceptions undergo. These changes, he holds, are the inner working of the conceptions themselves, the manifestation of our intellectual nature, ever striving for an ideal of logical consistency. Truth is this ideal. We do not make it; we move towards it. If we compare, then, the idealist and the pragmatist doctrine, it will seem that, while for the idealist truth is growing with advancing knowledge into an ever larger because more comprehensive system of reality, for the pragmatist it is ever narrowing, discarding failures as useless and irrelevant to present purpose. How indeed, the idealist will ask, if practical consequences be the meaning of truth, is it possible to understand that knowledge has advanced or can advance? Does not the history of science prove a continual expansion, an increasingcomprehension? It is within the conception that the inconsistency is revealed, not in any mere outward use of the conceptions, and the intellectual effort is to reconcile the contradiction by relating the conception to a more comprehensive whole. How, then, does the idealist meet this case which we have specially instanced, the demand for new notions of space and time made by the Principle of Relativity? He denies that the new conceptions are called forth by human needs in the narrow sense—that is to say, in the sense that working hypotheses or practical postulates are required. The need is purely logical. The inconsistency revealed in the notions that have hitherto served us can only be reconciled by apprehending a higher unity. If the older notions of space and time are inadequate to the more comprehensive view of the universe as a co-ordination of systems of movement, then this very negation of the older notions is the affirmation of the new, and from the negation by pure logic the content and meaning which are the truth of the new notions are derived. To this objection the pragmatist reply is that if this be the meaning of the truth there is no way shown by which it can be distinguished from error. There is in fact for idealism no error, no illusion, no falsehood; as real facts, there are only degrees of truth. But a theory of truth which ignores such stubborn realities as illusion, falsehood, and error is, from whatever standpoint we view it, useless. On the other hand, pragmatism offers a test by which we can discriminate between true and false—namely, the method of judging conceptions by their practical consequences. Can we or can we not make our conceptions work? That is the whole meaning of asking, Are they true or false? And now, lest the reader is alarmed at the prospect of having to revise his working ideas of space andtime, I will, to reassure him, quote the words with which Henri Poincaré concluded his account of the new conceptions, and which admirably express and illustrate the pragmatist's attitude: "What is to be our position in view of these new conceptions? Are we about to be forced to modify our conclusions? No, indeed: we had adopted a convention because it seemed to us convenient, and we declared that nothing could compel us to abandon it. To-day certain physicists wish to adopt a new convention. It is not because they are compelled to; they judge this new convention to be more convenient—that is all; and those who are not of this opinion can legitimately keep the old and so leave their old habits undisturbed. I think, between ourselves, that this is what they will do for a long time to come."
I have so far considered pragmatism rather as a criticism than as a doctrine. I will now try and characterise it on its positive side. It declares that there is no such thing as pure thought, but that all thinking is personal and purposive; that all knowing is directed, controlled, and qualified by psychological conditions such as interest, attention, desire, emotion, and the like; and that we cannot, as formal logic does, abstract from any of these, for logic itself is part of a psychical process. Truth therefore depends upon belief; truths are matters of belief, and beliefs are rules of action. It is this doctrine that gives to pragmatism its paradoxical, some have even said its grotesque, character. It seems to say that the same proposition is both true and false—true for the man who believes it, false for the man who cannot. It seems to say that we can make anything true by believing it, and we can believe anything so long as the consequences of acting on it are not absolutely disastrous. And the proposition, All truths work, seems to involve the conclusion that all that works is true; and the proposition, The true is the useful, seems to imply thatwhatever is useful is therefore true. No small part of the pragmatist controversy has been directed to the attempt to show that all and each of these corollaries are, or arise from, misconceptions of the doctrine. I think, and I shall endeavour to show, that there is a serious defect in the pragmatist statement, and that these misconceptions are in a great part due to it. Nevertheless, we must accept the pragmatist disavowal. And there is no difficulty in doing so, for the meaning of the theory is sufficiently clear. Truth, according to pragmatism, is a value and not a fact. Truth is thus connected with the conception of "good." In saying that truth is useful, we say that it is a means to an end, a good. It is not a moral end, but a cognitive end, just as "beauty" is an esthetic end. Truth, beauty, and goodness thus stand together as judgments of value or worth. It is only by recognising that truth is a value that we can possess an actual criterion to distinguish it from error, for if truth is a judgment of fact, if it asserts existence, so also does error.
The pragmatist principle has an important bearing on religion. It justifies the Faith attitude. It shows that the good aimed at by a "truth claim" is only attainable by the exercise of the will to believe. Thus it replaces the intellectual maxim, Believe in nothing you can possibly doubt, with the practical maxim, Resolve not to quench any impulse to believe because doubts of the truth are possible. Belief may even be a condition of the success of the truth claim.
We have seen in the last chapter that pragmatism is both a criticism and a theory. It shows us that thenotion that truth is correspondence involves the conception of an "impossible" knowledge, and the notion that truth is coherence or consistency involves the conception of a "useless" knowledge. The explanation pragmatism itself offers is of the kind that is called in the technical language of philosophy teleological. This means that to explain or to give a meaning to truth all we can do is to point out the purpose on account of which it exists. This is not scientific explanation. Physical science explains a fact or an event by showing the conditions which give rise to it or that determine its character. Pragmatism recognises no conditions determining truth such as those which science embodies in the conception of a natural law—that is, the idea of a connection of natural events with one another which is not dependent on human thoughts about them nor on human purposes in regard to them. Truth is in intimate association with human practical activity; its meaning lies wholly in its utility. We must therefore now examine somewhat closely this notion of utility.
There appears to me to be a serious defect in the pragmatist conception and application of the principle of utility; it is based on a conception altogether too narrow. A theory that condemns any purely logical process as resulting in "useless" knowledge can only justify itself by insisting on an application of the principle of utility that will be found to exclude not merely the Absolute of philosophy but most if not all of the results of pure mathematics and physics, for these sciences apply a method of pure logical deduction and induction indistinguishable from that which pragmatism condemns. The intellectual nature of man is an endowment which sharply distinguishes him from other forms of living creatures. So supreme a position does our intellect assign to us, so wide is the gap that separatesus from other creatures little different from ourselves in respect of perfection of material organisation and adaptation to environment, that it seems almost natural to suppose that our intellect is that for which we exist, and not merely a mode of controlling, directing, and advancing our life. Now it is possible to hold—and this is the view that I shall endeavour in what follows to develop—that the intellect is subservient to life, and that we can show the manner and method of its working and the purpose it serves. So far we may agree with the pragmatist, but it is not the same thing to say that the intellect serves a useful purpose and to say that truth, the ideal of the intellect, the end which it strives for, is itself only a utility. Were there no meaning in truth except that it is what works, were there no meaning independent of and altogether distinct from the practical consequences of belief, of what value to us would the intellect be? If the meaning the intellect assigns to truth is itself not true, how can the intellect serve us? The very essence of its service is reduced to nought; for what else but the conception of an objective truth, a logical reality independent of any and every psychological condition, is the utility that the intellect puts us in possession of? It is this conception alone that constitutes it an effective mode of activity. Therefore, if we hold with the pragmatist that the intellect is subservient to life, truth is indeed a utility, but it is a utility just because it has a meaning distinct from usefulness. On the other hand, to condemn any knowledge as "useless" is to deny utility to the intellect.
Before I try to show that the logical method of the idealist philosophy, which pragmatism condemns because it leads to "useless" knowledge, is identical in every respect with the method employed in pure mathematics and physics, I will give for comparison two illustrationsthat seem to me instances of a narrow and of a wide use of the concept of utility.
A short time ago an orang-utang escaped from its cage in the Zoological Gardens under somewhat singular and very interesting circumstances. The cage was secured with meshed wire of great strength, judged sufficient to resist the direct impact of the most powerful of the carnivora; but the ape, by attention to the twisting of the plied wire, had by constant trying succeeded in loosening and finally in unwinding a large section. It escaped from its enclosure, and after doing considerable damage in the corridor, including the tearing out of a window frame, made its way into the grounds and took refuge in a tree, twisting the branches into a platform said to be similar to the constructions it makes in its native forests.
In taking this action as an illustration, I am not concerned with the question of what may be the distinction between action that is intelligent and action that is instinctive. If we take intelligence in a wide and general meaning, we may compare the intelligence shown by this ape with the intelligence shown by man in the highest processes of the mind. Psychologists would, I think, be unanimous in holding that in the mind of the ape there was no conception of freedom, no kind of mental image of unrestricted life and of a distinct means of attaining it, no clearly purposed end, the means of attaining which was what prompted the undoing of the wire, such as we should certainly suppose in the case of a man in a similar situation. It was the kind of intelligent action that psychologists denote by the description "trial and error." It seems to me, however, that this exactly fulfils the conditions that the pragmatist doctrine of the meaning of truth require. We see the intellect of the ape making true by finding out what works.We can suppose an entire absence of the idea of objective truth to which reality must conform, of truth unaffected by purpose. Here, then, we seem to have the pure type of truth in its simplest conditions, a practical activity using intelligence to discover what works. Is the difference between this practical activity and the higher mental activities as we employ them in the abstract sciences one of degree of complexity only, or is it different in kind?
Let us consider now, as an illustration of the method of the abstract sciences, the well-known case of the discovery of the planet Neptune. This planet was discovered by calculation and deduction, and was only seen when its position had been so accurately determined that the astronomers who searched for it knew exactly the point of the heavens to which to direct their telescopes. The calculation was one of extraordinary intricacy, and was made independently by two mathematicians, Adams of Cambridge and Leverrier of Paris, between the years 1843 and 1846. Each communicated his result independently—Adams to the astronomer Challis, the Director of the Cambridge Observatory, and Leverrier to Dr. Galle of the Berlin Observatory. Within six weeks of one another and entirely unknown to one another, in August and September 1846, each of these astronomers observed the planet where he had been told to look for it. This is one of the romances of modern science. It is not the discovery but the method that led to it which may throw light on our problem of the nature of truth.
At first sight this seems exactly to accord with and even to illustrate the pragmatist theory, that truth is what works. The investigation is prompted by the discrepancies between the actual and the calculated positions of Uranus, the outermost planet, as it was then supposed, of the system. This revealed a need, and thisneed was met by the practical postulate of the existence of another planet as yet unseen. The hypothesis was found to work even before the actual observation put the final seal of actuality on the discovery. What else but the practical consequences of the truth claim in the form of the hypothesis of an undiscovered planet were ever in question? Yes, we reply, but the actual method adopted, and the knowledge sought for by the method, are precisely of the kind that pragmatism rejects as "useless" knowledge. Why were not the observed movements of Uranus accepted as what they were? Why was it felt that they must be other than they were seen to be unless there was another planet? The need lay in the idea of system. It was inconsistent with the system then believed complete, and the need was to find the complete system in which it would harmonise. The truth that was sought for was a harmonious individual whole, and the method employed precisely that which the Absolutist theory of reality employs. There is observed a discrepancy, an inconsistency, a contradiction within the whole conceived as a system. This negation is treated as a defect, is calculated and accurately determined, and is then positively affirmed of the reality. Now, what is distinctive in this method is that reality is conceived as a complete system. If the felt defect in this system cannot be made good by direct discovery, its place is supplied by a fiction, using the term in its etymological meaning to express something made and not in its derived meaning to express something found false. This intellectual process of construction is purely logical; no psychological element in the sense of the will to believe enters into it or colours it in any way.
This is not an isolated instance, it illustrates the method of science in all theorising. An even morestriking illustration than that we have just given is the case of the hypothesis of the luminiferous æther—a supposed existence, a fiction, that has served a useful, even an indispensable service in the history of modern physics. To many physicists, even to Lord Kelvin, the hypothesis seemed so surely established that its nonexistence hardly seemed thinkable, yet all the experiments designed to detect its presence have been uniformly negative in result, and it now seems not even necessary as a hypothesis, and likely to disappear. The æther was not only not discovered, it was not even suspected to exist, as in the case of the unknown planet Neptune—it was logically constructed. It was required to support the theory of the undulatory nature of light and to fulfil the possibility of light propagation in space. It was therefore a postulate, called forth by a need—so far we may adopt the pragmatist account. But what was the nature of the need, and what was the method by which the postulate was called forth? It is in answering this question that the pragmatist criterion fails. The need was intellectual in the purely logical meaning of the term, and it was met by a purely logical construction. The need was a practical human need only in so far as the intellect working by logical process is a human endowment but not in any personal sense such as is conveyed by the term psychological. Willingness or unwillingness to believe, desire, aversion, interest were all irrelevant. Given the intellect, the logical necessity was the only need that called forth by logical process the "truth-claiming" hypothesis of the æther. But even so, the pragmatist will urge, is its truth anything else but its usefulness as shown in the practical consequences of believing it? Was it not true while it was useful, and is it not only now false, if it is false, if it is actually discovered not to be useful?The reply is that no mathematician or physicist would recognise the possibility of working with a conception of truth that simply identified truth with utility, and for this reason that he can only conceive reality as a system whose truth is symbolised in an equation. It is the system that determines and characterises the postulate, and not the postulate advanced at a venture, tried and verified, that constitutes the system. The mathematician begins by placing symbols to represent the unknown factors in his equation, and proceeds by means of his known factors to determine their value. The æther is at first a pure fiction constructed to supply an unknown existence recognised as a defect. Its truth cannot mean that it works for it cannot but work, having been constructed purely for that purpose. Its truth means that it corresponds to some actual existence at present unknown. To prove its truth the physicist does not appeal to its value as a hypothesis, but devises experiments by which, if it does exist, its existence will be demonstrated. In this actual case the experiments have had a uniformly negative result, and therefore the truth of the hypothesis is made doubtful or denied. The hypothesis continues to work as well as it ever did, and physicists will probably long continue to use it, but it has failed to establish its truth claim. The result is the modern Principle of Relativity, which, as we have already said, has produced a revolution in modern physics. The abolition of the æther would have been impossible if the physicist had been content with the utility of his hypothesis and had not experimented to prove its truth. The relation between truth and utility is thus proved to be that it is useful to know what is true.
These two illustrations of scientific method—namely, the discovery of Neptune and the negative discoverythat the æther is non-existent—make it evident that verification is the intellectual process not of making true, but of finding true. We can, indeed, distinguish quite clearly the two processes. The first process, that of making true, is the constructing of the fiction by which we complete an incomplete system, and the second is the testing of that fiction to see if it corresponds to anything actually existing. No kind of intellectual activity will make an idea true, and conversely we may say that were truth only a utility, then knowledge instead of being systematic would be chaotic. Existence has its roots in reality, not in knowledge. Reality does not depend on truth. Truth is the intellectual apprehension of reality.
If the pragmatist objects that in this argument I have throughout supposed him to be urging the narrow meaning of utility, namely, that it is usefulness in the strictly practical sense, whereas he intends it in the widest possible meaning—a meaning that includes theoretical usefulness—then the trouble is a different one; it is to know how and where the pragmatist stops short of the coherence theory of truth, and wherein his method differs from that of the idealist.
This brings me to the consideration of another theory in which the concept of utility plays a large, indeed a predominant part. This is the theory of the relation of knowledge to life that is given to us in the philosophy of Bergson. I have in one of the volumes of this series given an account of this philosophy; I am here only dealing with its relation to this special problem of the nature of truth. It has been claimed that this philosophy is only a form of pragmatism, but it is not a theory of truth, and it has this essential difference from pragmatism that it is the intellect and not truth that is a utility. Before we consider the question that it givesrise to in regard to truth, let us first examine the theory of the intellect, and the nature of its utility. The intellect is a mode of activity, an endowment acquired in the course of evolution, and which has been retained and perfected because of its utility. This does not mean that the intellect directs us to what is useful and inhibits us from courses fatal to life, neither does it mean that it gives us any power to make true what is not already true, it means that the power to acquire knowledge is useful. There is a contrast in our own existence between our life and our intellect.
To understand the way in which the intellect serves the living creature endowed with it, we need only regard it from the standpoint of ordinary experience. We know in ourselves that our life is wider than our intellect, and that our intellect serves the activity of our life. The common expressions we employ, such as using our wits, taking an intelligent interest, trying to think, all imply a utility distinct from the intellect. So viewed, our life appears as an active principle within us, maintaining our organism in its relations, active and passive, and reactive to the reality outside and independent of it. Our intellect also seems both active and passive. It receives the influences that stream in upon us from the reality around us, it apprehends and interprets them, and works out the lines of our possible action in regard to them. The influences that flow in upon us from the outside world are already selected before our intellect apprehends them, for they flow in by the avenues of our senses, and the senses are natural instruments of selection. If we picture these influences as vibrations, then we may say that a certain group of vibrations of a very rapid frequency are selected by the eye and give rise to vision, that another group of very much lower frequency are selected by the ear andgive the sensation of sound, and other groups are selected by taste, smell, and touch. Many groups are known indirectly by means of artificial instruments, and all the infinite series that unite these groups of the actually experienced vibrations escape our apprehension altogether—we have no means of selecting them. But all these sense data, as we may call them, come to us without exertion or activity on our part; it is the intellect which gives them meaning, which interprets them, which makes them the apprehension or awareness of objects or things. And the active part that the intellect plays is also a process of selection. This is evident if we reflect upon the universal form which our intellectual activity takes, namely, attention. It is in the act of attention that we are conscious of mental activity, and attention is essentially selection—the selection of an interest. Besides the natural selection that is effected by our senses and the conscious selection that is manifest in attention, there is also a more or less arbitrary selection that our intellect performs in marking out the lines of our practical interest and possible action. In this work of selection the intellect makes the world conform to the necessities of our action.
So far we have looked at our intellectual endowment from the standpoint of ordinary common-sense experience. Let us now consider the philosophical theory based on this view, which explains the nature of knowledge by showing its purpose. The intellect not only selects, but in selecting transforms the reality. It presents us with knowledge that indeed corresponds with reality, for it is essentially a view of reality, but also in selecting it marks out divisions, and gives to reality a form that is determined by practical interest. The same reality is different to different individuals and to different species according to their practical interests.The practical end which the human intellect serves is to present us with a field for our life activity. This is the real world for us, as we know it, real objects in a real space. Had we no other way of knowing but that of our intellect we should not know the life which is active within us as it is really lived, we should be as those who, standing outside, watch a movement, and not as those who are carried along in the movement and experience it from within. In life and intellect we have the counterpart of reality and appearance. Life is not something that changes; it is the change of which the something is the appearance. Life is the reality of which all things, as we understand them, are the appearances, and on account of which they appear. The solid things in space and time are not in reality what they appear; they are views of the reality. The intellect guided by our practical interest presents reality under this form of solid spatial things. Clearly, then, if this view be true, the whole world, as it is presented to us and thought of by us, is an illusion. Our science is not unreal, but it is a transformed reality. The illusions may be useful, may, indeed, be necessary and indispensable, but nevertheless it is illusion.
But here there arises a new difficulty in regard to truth. If the usefulness of the intellect consists in the active production of an illusion, can we say that the intellect leads us to truth? Is it not only if we can turn away from the intellect and obtain a non-intellectual intuition that we can know truth?
The doctrine that the world that appears is essentially unlike the world that is is neither new nor peculiar to any particular theory of philosophy. It has received a new interest and a new interpretation lately in the theory that we are now considering, that the clue to the appearance of the world to us is to be found in the conception of the nature of the utility of the intellect and in the mode of its activity. The idea that we are perhaps disqualified by our very nature itself from beholding reality and knowing truth is illustrated in the well-known allegory in theRepublicof Plato:
"And now let me show in a figure how far our nature is enlightened or unenlightened. Behold! human beings living in an underground den, which has a mouth open towards the light and reaching all along the den; here they have been from their childhood, and have their legs and necks chained so that they cannot move and can only see before them, being prevented by the chains from turning round their heads. Above and behind them a fire is blazing at a distance, and between the fire and the prisoners there is a raised way; and you will see, if you look, a low wall built along the way, like the screen which marionette players have in front of them, over which they show the puppets. And men are passing along the wall carrying all sorts of vessels, and statues, and figures of animals made of wood and stone and various materials, which appear over the wall....
"They are strange prisoners, like ourselves, and they see only their own shadows or the shadows of one another which the fire throws on the opposite wall of the cave. And so also of the objects carried and of the passers-by; to the prisoners the truth would be literally nothing but the shadows of the images.
"And now look again, and see what will naturally follow if the prisoners are released and disabused of their error. At first, when any of them, is liberated and compelled suddenly to stand up and turn his neck round and walk and look towards the light, he will suffer sharp pains; the glare will distress him, and he will be unable to see the realities of which in his former state he had seen the shadows. And then conceive someone saying to him that what he saw before was an illusion, but that now, when he is approaching nearer to being, and his eye is turned towards more real existence, he has a clearer vision, and what will be his reply? Will he not fancy that the shadows which he formerly saw are truer than the objects which are now shown to him?...
"And suppose that he is forced into the presence of the sun himself, is he not likely to be pained and irritated? When he approaches the light his eyes will be dazzled, and he will not be able to see anything at all of what are now called realities."
The thought that Plato has expressed in this wonderful allegory has entered deeply into all philosophy. What we first take for reality is merely a shadow world. But in Plato's view it is the intellect which gives us the means of escape, the power to turn from the illusion to behold the reality. It is not until now that philosophy has sought the clue to the illusion in the nature of the intellect itself. The very instrument of truth is unfitted to reveal to us the reality as it is, because its nature and purpose is to transform reality, to make reality appear in a form which, though of paramount importance to us as active beings, is essentially an illusion. The intellectual bent of our mind leads us away from, and not towards a vision of reality in its purity. The more our intellect progresses, and the more and more clearly wesee into a greater and ever greater number of things, the farther are we from, and not the nearer to a grasp of reality as it is. To obtain this vision of reality we have to turn away from the intellect and find ourselves again in that wider life out of which the intellect is formed. Life, as it lives, is an intuition that is nonintellectual.
"Human intelligence," writes Bergson, "is not at all what Plato taught in the allegory of the cave. Its function is not to look at passing shadows, nor yet to turn itself round and contemplate the glaring sun. It has something else to do. Harnessed, like yoked oxen, to a heavy task, we feel the play of our muscles and joints, the weight of the plough, and the resistance of the soil. To act and to know that we are acting, to come into touch with reality and even to live it, but only in the measure in which it concerns the work that is being accomplished and the furrow that is being ploughed, such is the function of human intelligence."
The illusion to which our intellectual nature subjects us is the necessity we are under to regard the things of the universe as more ultimate, as more fundamental than the movement which actuates the universe. It seems to us impossible that there could exist movement or change, unless there already existed things to be moved or changed, things whose nature is not altered, but only their form and their external relations, when they are moved or changed. This necessity of thought seems to have received authoritative recognition in all attempts, religious and scientific, to conceive origins. Thus we read in the Book of Genesis:
"In the beginning God created the heaven and the earth. And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters."
The matter of the universe, it is felt, must be in existence before the movement which vivifies it. The dead inert stuff must be created before it can receive the breath of life. And if God the creator is conceived as living before the matter which He has created, it is as an external principle, the relation of which to the creation is by most religious minds thought to transcend the power of the finite understanding to conceive.
The same fundamental conception of the primacy of matter over movement is evident in the scientific theories of the nature and origin of life. Life appears to science as a form of energy that requires things, matter occupying space, to support it. According to one view, life is the result of a certain combination or synthesis of chemical or physical elements, previously existing separately—a combination of very great complexity, and one that may possibly have occurred once only in the long process of nature, but which nevertheless might be, and some think probably, or even certainly, will be brought about by a chemist working in his laboratory. This is the mechanistic or materialist view. On the other hand, there is the theory of vitalism. Life, it is contended, cannot be due to such a synthesis of material elements as the mechanistic view supposes, because it is of the nature of an "entelechy"—that is, an individual existence which functions, as a whole, in every minutest part of the organism it "vitalises." Life has supervened upon, and not arisen out of the material organism which it guides and controls not by relating independent parts, but by making every part subserve the activity and unity of the whole. But the vitalist theory, as well as the mechanistic theory, conceives the movement and change which is life as dependent on the previous existence of a matter or stuff which is moved or changed. The philosophicalconception differs, therefore, from both these theories. It is that life is an original movement, and that this movement is the whole reality of which things, inert matter, even spatial extension, are appearances. True duration is change, not the permanence of something amidst change. There are no unchanging things. Everything changes. Reality is the flux; things are views of the flux, arrests or contractions of the flowing that the intellect makes. The appearance of the world to us is our intellectual grasp of a reality that flows. This original movement is the life of the universe. Briefly stated, the argument on which the theory is based is that it is logically impossible to explain change by changelessness, movement by immobility. Real change cannot be a succession of states themselves fixed and changeless; real movement cannot be the immobile positions in which some thing is successively at rest. On the other hand, if movement is original, the interruption of movement, in whatever way effected, will appear as things. The experience which confirms this argument is the insight that everyone may obtain of the reality of his own life as continuous movement, unceasing change, wherein all that exists exists together in a present activity. To develop this argument would exceed the limits of this book, and would be outside its purpose. It is essential, however, that such a theory should be understood, for clearly it is possible to hold not only that we are subject to illusion, but that illusion is of the very nature of intellectual apprehension. If, then, the understanding works illusion for the sake of action, is it thereby disqualified as an instrument for the attainment of truth?
We are brought, then, to the critical point of our inquiry. If illusion is the essential condition of human activity, if the intellect, the very instrument of truth,is itself affected, what is to save us from universal scepticism? If the salt have lost his savour, wherewith shall it be salted? The intellect with its frames and moulds shapes living change and movement into fixed immobile states; the process of knowing alters profoundly the reality known. Must we not conclude that knowledge, however useful, is not true? And to what shall we turn for truth? There is, indeed, if this be so, a deeper irony in the question, What is truth? than even Pilate could have imagined. We have absolutely no practical concern with truth—we must leave it to the mystic, to the unpractical, the contemplative man who has turned aside from the stern task of busy life.
It is not so. The problem that seems so fundamental admits a quite simple solution. Illusion is not error, nor is it falsehood; it is the appearance of reality. It is the reality that appears, and when we grasp the principle of utility we understand the shape that the appearance must assume. This shape may seem to us a distortion, but in recognising appearance we are in touch with reality, and practical interest is the key that opens to us the interpretation of intellectual experience. And it is not only by the intellect that we interpret the nature of reality, for besides logic there is life, and in life we directly perceive the reality that in logic we think about.
The intellect, then, does not make truth, neither does it make reality; it makes reality take the form of spatial things, and it makes things seem to be the ground of reality. Were our nature not intellectual, if all consciousness was intuitive, the world would not then appear as things—there would be no things. But, notwithstanding that our world is an illusion, it is not the less on that account a true world, and our science is true knowledge, in the objective meaning of truth, foronce an illusion is interpreted, it becomes an integral part of the conception of reality. It would be easy to find abundant illustration of this fact within science itself. Thus in the familiar case of the straight stick which appears bent when partly immersed in water, as soon as the illusion is understood as due to the different refraction of light in media of different density, air and water, it ceases to be an illusion. We then recognise that if a partly immersed stick did not appear bent, it would really be bent. Again, the illusion that clings to us most persistently throughout our experience is that which is connected with movement and rest. The system of movement in which we are ourselves carried along appears to us stationary, while that which is outside it seems alone to move. In very simple cases, such as viewing the landscape from a railway-carriage window, habit has long caused the illusion to cease, but we all remember the child's feeling that the trees and fields were flying past us. The earth's motion never becomes to us a real experience of movement, we accept the fact and never doubt the scientific evidence on which it rests, yet we always speak and think of sunrise and sunset; and this is not merely due to the accident that our language was fixed before the nature of the celestial movement was known, but to a natural illusion which it is far more convenient to retain than to abandon.
The fact of illusion is not the tenet of any particular philosophy, nor even of philosophy itself; it is a recognised factor in common life and in physical science, but in instancing the theory of Bergson's philosophy I am choosing an extreme case. Berkeley held that illusion is practically universal; Kant taught that the apparent objectivity of phenomena is the form that the understanding imposes on things; but Bergson teachesnot only that all material reality is illusion, but also that this very illusion is the work of the intellect, that the intellect is formed for this purpose, intellect and matter being correlative, evolvingpari passu. To such a doctrine there is of necessity a positive side, for it is impossible that it can rest on universal scepticism—scepticism both of knowledge and of the instrument of knowledge. If the intellectual view of reality as solid matter in absolute space is illusion, it must be possible to apprehend the reality from which the judgment that it is illusion is derived. If the intellect distorts, there must be an intuition which is pure, and the relation between these will be the relation between reality and appearance. Neither, then, is reality truth, nor appearance error. There is a truth of appearance, a truth that is a value in itself, a truth that is more than the mere negation that appearance is not reality. The appearance is our hold upon the reality, our actual contact with it, the mode and direction of our action upon it. What, then, is error? It cannot consist in the fact that we know appearance only, not reality, for we can only know reality by its appearance. It cannot be an appearance behind which there is no reality, for non-being cannot appear. It cannot be nothing at all or pure non-being, for to think of absolute nothing is not to think. In error there is some object of thought which is denied real being. What this is is the problem of error.
In theTheætetusof Plato, Socrates has been discussing with Theætetus what knowledge is, and when at last agreement seems to be reached in the definition thatknowledge is true opinion, a new difficulty occurs to Socrates:
"There is a point which often troubles me and is a great perplexity to me both in regard to myself and to others. I cannot make out the nature or origin of the mental experience to which I refer. How there can be false opinion—that difficulty still troubles the eye of my mind. Do we not speak of false opinion, and say that one man holds a false and another a true opinion, as though there were some natural distinction between them? All things and everything are either known or not known. He who knows, cannot but know; and he who does not know, cannot know.... Where, then, is false opinion? For if all things are either known or unknown, there can be no opinion which is not comprehended under this alternative, and so false opinion is excluded."
This difficulty may appear at first sight purely verbal, and we shall perhaps be inclined to see the answer to it in the double use that we make of the word knowledge. We use the word in two senses, in one of which it includes all and everything that is or can be present to the mind in thinking, and in another and narrower sense the word knowledge means truth. It was in the narrow sense of the word that whatever is not true is not knowledge that Socrates interpreted the meaning of the Delphic oracle that had declared him the wisest of men. His wisdom must be, he said, that whereas other men seemed to be wise and to know something, he knew that he knew nothing. All men have opinion, but opinion is not knowledge, though easily and generally mistaken for it. His perplexity was to understand what actually this false opinion could be which passed for knowledge. It could not be nothing at all, for then it would simply mean ignorance; but in false opinionsome object is present to the mind. Everything that the mind thinks of has being. A thing may have being that does not exist if by existence is meant the particular existence of an event in time, for most of the things we think about are timeless—they are ideas, such as whiteness, goodness, numbers and the properties of numbers, faith, love, and such-like. All such ideas are called universals, because their reality does not mean that they exist at one particular moment and no other, but they are real, they have being. How, then, can there be anything intermediate between being and not being, anything that is and also is not, for this is what false opinion or error seems to be?
There is, then, a problem of error, and it is quite distinct from the problem of truth. The problem of truth is to know by what criterion we can test the agreement of our ideas with reality; the problem of error is to know how there can be false opinion. There is false opinion, of this no one needs to be convinced; but where its place is in the fundamental scheme of the mental process, in what precisely it consists, whether it is purely a negation or whether it has a positive nature of its own, this is the problem we have now to consider.
There is an important distinction in logic between what is contradictory and what is contrary. Of two contradictory propositions one must be true, the other must be false; but of two contrary propositions one must be false, but both may be false. Of contradictory propositions one is always a pure negation, one declares the non-existence of what the other affirms the existence; but of contrary propositions each has a positive content, and both may be false. A true proposition may be based on a false opinion, and it is very important to have a clear idea of what we intend by false opinion. We do not mean by false opinion such plainly falsepropositions as that two and two are five or that there may be no corners in a square—such propositions are false, because they contradict propositions that are self-evident. If anyone should seriously affirm them, we should not, I think, say that such a one had a false opinion, but that he failed, perhaps through some illusion, to understand the meaning of the terms he was using. An example of what would now, I suppose, be unquestionably regarded by everyone as error is that whole body of opinion that found expression in the theory and practice of witchcraft. This was once almost universally accepted, and though probably at no period nor in any country was there not some one who doubted or disbelieved, still the reasons of such doubt or disbelief would probably be very different from those reasons which lead us to reject it to-day. For witchcraft was grounded on a general belief that spiritual agencies, beneficent and malign, were the cause of material well-being or evil. This conception has now given place to the mechanistic or naturalistic theory on which our modern physical science is based. We interpret all physical occurrences as caused by material agency. But this belief, quite as much as the belief in spiritual agencies, is opinion, not knowledge, and it may be false. It is conceivable that future generations will reject our scientific notions, self-evident though they seem to us, as completely as we reject the notions of the dark ages. It is even conceivable that the whole of our modern science may come to appear to mankind as not even an approximation to knowledge. Error, like illusion, may be universal. No one whose opinion counts as a rational belief now holds that sickness may be caused by the malign influence of the evil eye, and that this influence may be neutralised by making the sign of the cross; some, but very few, believe that asick man may be healed by the prayers and anointing of righteous men; many believe that material disease, however malignant, may be expelled from the body by faith; while the majority of rational men, whatever independent religious views they hold, regard sickness and disease as material in the ordinary sense, and expect them to yield to drugs and treatment. Now, of these various opinions some must be false, while all may be false. Let us add some illustrations from philosophy. Some philosophers hold, in common with general opinion, that sense experience is caused by physical objects; others hold that there are no physical objects, but that consciousness is the one and only reality; and there are others who think that the reality that gives rise to our sense experience is neither physical in the sense of a material thing, nor mental in the sense of consciousness or thought, but is movement or change—change that requires no support and is absolute. All these are opinions, and may be false, and our belief that any one of them is true does not depend on immediate experience, but on reasons. The best that can be said in favour of any belief is that there is no reason for supposing it false, and the worst that can be said against any belief is that there is no reason for supposing it true. Our problem, then, is to know what constitutes the nature of error in any one of these examples if it is, as each one may be, false?
The instances we have given are all of them propositions or judgments, or else conceptions formed out of propositions or judgments, the purpose of which is to interpret experience. The actual experience itself, in so far as it consists of the actual presence of the object to the mind aware of it, is, as we have seen, neither truth nor error; it simply is what it is. It is the conceptions by which we interpret this experience that aretrue or false. And our problem is that the meaning or content of a conception, that which is present to the mind when we make a judgment, is precisely the same whether the conception is true or false, there is no distinctive mark or feature by which we can know that in the one case the object of thought is a real or actual fact, in the other an opinion to which no reality corresponds. And, further, it seems exceedingly difficult to understand in what way a non-reality can be present to the mind at all.
Let us now examine some attempts to solve this problem, and first of all let us take the pragmatist solution. Pragmatism claims that it has no difficulty in explaining error, because, as we have already seen, it acknowledges no other test or criterion of truth except a pragmatic one. Every proposition or judgment that we make must, in order to have any meaning whatever, be relevant to some human purpose; every such proposition is a truth-claim; and every truth-claim is tested by its workability. Consequently, error is simply the failure of a proposition to establish its claim by the practical test of working. Propositions marked by such failure are errors. As there is no truth independent of time, place, and circumstance, no irrelevant truth, no truth independent of the conditions under which its claim is put forward, there is no truth that may not become error. No judgment, according to pragmatism, is an error pure and simple—that is to say, it cannot come into existence as error, for it comes claiming truth, and maintaining that claim until challenged; it becomes an error in retrospect only, and always in relation to another judgment which corrects it. Error does not characterise a class of judgments; it is something that happens to a judgment, it is a judgment whose truth-claim is rejected in reference to another judgmentwhich succeeds. The essential thing in the pragmatist doctrine of error is that in claiming to be true a judgment is not challenging comparison with some independent reality, nor is it claiming to belong to a timeless order of existence—to be eternal; it is claiming to fulfil the particular purpose for which it has been called forth, whether that purpose be practical or theoretical.
Let us now consider the explanation of error offered by the idealist philosophy. In this view only the whole truth is wholly true; the Absolute, as a perfect, concrete, individual system, is the ideal, and all that falls short of it can only possess a degree of truth—a degree which is greater or less according as it approximates to the ideal. The degrees of truth are not quantitative, not a mixture of truth and error, but a nearer or more distant approach to the ideal. There can be no absolute error, because if truth is the whole, error, if it exists at all, must in some way be included in truth. Clearly error cannot as such be truth, and therefore it must follow that, in the whole, error loses its character of error, and finds reconciliation of its contradiction to truth. Error, then, if it is something, and not a pure negation, is partial or incomplete truth; the perplexity and contradiction that it gives rise to are incidental to our partial view. Knowledge, it must seem to us, can exist only for omniscience. Unless we know everything, we know nothing.
These two doctrines are in a sense the exact antithesis of one another. They agree together in this, that in each the explanation of error follows as a consequence of the conception of the nature of truth. The pragmatist theory implies that there is no truth in any real sense, but only more or less successful error. The idealist theory implies that there is no real error, but only a variety in the degree of truth.
Most people, however, are convinced that truth and error are not related to one another, nor to the circumstances that call forth belief or disbelief. Let us now examine a theory that recognises this. There are false judgments, and they need explanation; error has a nature of its own. If a judgment is false, it is absolutely and unalterably false; if it is true, it is unconditionally true and with no reserve. No logical process, no psychological disposition, can make what is false true. Error must lie in the nature of knowledge, and to discover that nature we must understand the theory of knowledge and determine the exact nature of the mental act in knowing. The first essential is to distinguish the kind of knowledge to which truth and error can apply. We pointed out in the second chapter that all knowledge rests ultimately on immediate experience. In immediate experience the relation between the mental act of knowing and the object that is known is so simple that any question as to truth or error in regard to it is unmeaning. To question the truth of immediate experience is to question its existence; it is to ask if it is what it is, and this is plainly unmeaning. But thinking, we said, is questioning experience in order to know its content or meaning, and in thinking, the simplicity of the relation which unites the mind to its object in immediate experience is left behind, and a logical process of very great complexity takes its place. It is in this complexity that the possibility of error lies.
Let us look at it a little more closely. Knowing is a relation which unites two things, one the mind that knows, the other the thing known. In every act of knowing, something is present to the mind; if knowing is simply awareness of this actually present something, we call it immediate experience, we are acquainted with the object. But our knowledge is not only of objectsimmediately present to the mind and with which we are therefore acquainted. Knowledge embraces the past and future and the distant realms of space. Indeed were knowledge only of what is actually present to the mind, it is difficult to imagine that we could, in the ordinary meaning of the word, know anything at all. I may be thinking, for example, of an absent friend; all that is present to my mind is, it may be, a memory image, a faint recall of his appearance on some one occasion, or perhaps a recollection of the tone of his voice, or it may be the black marks on white paper which I recognise as his handwriting. This image is present to my mind, but the image is not the object, my friend, about whom I think and make endless judgments, true and false. So also, if what is present to the mind is affecting me through the external senses, if it is a sense impression, it is clear that what is actually present is not the whole object of which I am aware, but only a very small part of it, or, it may be, no part of it at all, but something, a sound, or an odour, that represents it. The immediate data of consciousness are named by some philosophers sense data, by others, presentations, by others images, and there is much controversy as to their nature and existence, but with this controversy we are not here concerned—we are seeking to make clear an obvious distinction, namely, the distinction between knowledge by acquaintance and knowledge by description.
What kind of knowledge is it that we acquire by description? Knowledge about things with which we are not first acquainted. The most important knowledge that we possess or acquire is knowledge of objects which we know only by the knowledge we have about them—objects that we know about without knowing them. They are not direct impressions on our senses,nor are they ideas known in actual experience. We make judgments about them, and the subjects about which we make these judgments are really composed of these judgments that we make about them. To go back to our illustrations, we may know a great deal about the evil eye, a malignant influence, disease, faith, healing, causality, physical objects, without any acquaintance with them, without even knowing that they exist. Such knowledge is descriptive, and the objects are descriptions. Knowledge by description is never quite simple, and is often very complex, for, besides the relation of the mental act to the object known, there are the terms and relations which are the elements in the judgment and the relations of the judgments themselves. If we analyse a judgment, every word in which it is expressed, whether it is a noun or a verb or a preposition or a conjunction, conveys a distinct meaning, indicates a term or a relation, each of which can be made a distinct object to the mind, and all of which are combined in the single meaning the judgment expresses. It is in this complexity that the possibility of error lies, and the possibility increases as the complexity increases. All the terms and the relations which a judgment contains depend on the knowledge we have by acquaintance—that is to say, we are ultimately dependent on our actual experience for all knowledge whatever, whether it is acquaintance or description, for we can only describe in terms with which we are acquainted; but in the judgment these elements are combined into new objects, or a certain relation is declared to exist between objects, and it is this combination of the elements of the judgment that involves its truth or falsehood.
If this view of the nature of the mental act of knowing is accepted, we are able to understand how false opinionis consistent with the fact that all knowledge is truth. We escape both the alternatives that seemed to Socrates the only possible ones. "When a man has a false opinion, does he think that which he knows to be some other thing which he knows, and knowing both is he at the same time ignorant of both? Or does he think of something which he does not know as some other thing which he does not know?" No, neither; in error he thinks that something that he knows is in a relation that he knows to some other thing that he knows, when in fact that relation is not relating the two things. The false proposition is not one in which the constituent terms and relations are unknown or non-existent, but one in which a combination of these terms and relations is thought to exist when in fact it does not exist; and the true proposition is that in which the combination thought to exist does exist. We can, therefore, if this account be true, at least know what false opinion or error can be, whether or not we have any means of deciding in regard to any particular opinion that it is false.
There is one other theory, the last we shall notice. It is in one respect the most important of all, namely, that it is the most direct attempt to grapple with the problem of error. It is founded on a theory of knowledge which we owe mainly to the profound and acute work of a German philosopher (Meinong), and which at the present time is being keenly discussed. It is an attempt to determine more exactly than has yet been done the fundamental scheme of the mental life and development. The brief account that I am now offering, I owe to a paper by Prof. G. F. Stout on "Some Fundamental Points in the Theory of Knowledge." We have seen that the problem of error is the difficulty there is in conceiving how there can be any real thing, any realobject of thought, intermediate between being and not-being. Error seems to exist and yet to have a nature which is a negation of existence, and it seems therefore to be a downright contradiction when we affirm that error or false opinion canbe—that there is a real object of thought when we judge falsely. This theory meets the difficulty directly by distinguishing in the mental act of knowing a process that is neither perceiving nor thinking of things, and that involves neither believing nor disbelieving on the one hand nor desiring or willing on the other: this is the process of supposing. Corresponding to this mental act of supposing, there is a distinct kind of object intended or meant by the mind—an object that is neither a sense datum nor an idea, nor a judgment, but a supposition. Also and again corresponding to this mental act of supposing and its intended object the supposition, there is a mode of being which is neither existence nor non-existence, but is named subsistence. A supposition, it is said, does not exist—it subsists. This thesis, it will easily be understood, is based on an analysis, and deals with arguments that touch the most fundamental problems of theory of knowledge. Moreover, its presentment is excessively technical, and only those highly trained in the habit of psychological introspection and skilled in philosophical analysis are really competent to discuss it. It is not possible to offer here anything but a simple outline of the part of the theory that concerns the present problem. The actual experience of knowing is a relation between two things, one of which is a mentalact, the act of perceiving or thinking or having ideas, and the other is anobject, that which is perceived or thought of. The act is a particular mental existence, it is the act of a psychical individual. The object is not included within the actual experience which is the knowing of it, it isthat which is meant or intended by the experience. The act, then, is the mental process of meaning or intending, the object the thing meant or intended. The mental act differs according to the kind of object intended. The act of perceiving is the direction of the mind towards sense data and ideas; the act of judging is the direction of the mind towards judgments or propositions about things, propositions that affirm or deny relations between things; the act of supposing is different from both these—it is the direction of the mind towards suppositions. Suppositions differ from ideas in this, that they may be either positive or negative, whereas ideas are never negative. This may seem to contradict experience. Can we not, for example, have an idea of not-red just as well as an idea of red? No, the two ideas can easily be seen to be one and the same; in each case it is red we are actually acquainted with, and the difference is in affirming or denying existence to the one idea. The difference is in our judgment, which may be affirmative or negative. A supposition is like a judgment in this respect; it may be either affirmative or negative, but it differs from a judgment in another respect, that while a judgment always conveys a conviction, always expresses belief or disbelief, a supposition does not—it is neither believed nor disbelieved.
Before I show the application of this analysis of knowledge to the problem of error, let me try and clear up its obscurity, for undoubtedly it is difficult to comprehend. Its difficulty lies in this, that though all the ideas with which it deals are quite familiar—suppositions, real and unreal possibilities, fulfilled and non-fulfilled beliefs—yet it seems to run counter to all our notions of the extreme simplicity of the appeal to reality. It seems strange and paradoxical to our ordinary habitof thinking to affirm that there are real things and real relations between things which though real yet do not exist, and also that non-existent realities are not things that once were real but now are nought—they are things that subsist. Yet this is no new doctrine. The most familiar case of such realities is that of numbers. The Greeks discovered that numbers do not exist—that is to say, that their reality is of another kind to that which we denote by existence. Numbers are realities, otherwise there would be no science of mathematics. Pythagoras (about 540-500 B.C.) taught that numbers are the reality from which all else is derived. And there are many other things of the mind that seem indeed to be more real than the things of sense. It is this very problem of error that brings into relief this most important doctrine.
Now let us apply this theory of the supposition to the problem of error, and we shall then see how there can be an object present to the mind when we judge falsely, and also that the object is the same whether we judge truly or falsely. Suppositions are real possibilities; they are alternatives that may be fulfilled or that may never be fulfilled. These real possibilities, or these possible alternatives, are objects of thought; they do not belong to the mental act of thinking; they are not in the mind, but realities present to the mind. In mere supposing they are present as alternatives; in judging, we affirm of them or deny of them the relation to general reality that they are fulfilled. Judgments therefore are true or false accordingly as the fulfilment they affirm does or does not agree with reality. In this way, then, we may answer the perplexing question, How can there be an object of thought in a false judgment? The answer is, that the objects of thought about which we make judgments are suppositions, and our judgmentsconcern their fulfilment, and their fulfilment is a relation external to them—it is their agreement or disagreement with reality.