postulate.

This continuous process of selection and rejection of 'principles' and 'facts' has, as we have said, a thoroughly biological tinge. The fitness of a postulate to survive is being continually tested. It springs in the first place from a human hope that events may be systematized in a certain way, and it endures so long as it enables men to deal with them in that way. If it fails, the formation of fresh ideals and fresh hypotheses is demanded; but that which causes one postulate to prevail over another is always the satisfaction which, if successful, it promises to some need or desire. Thus 'thought' is everywhere inspired by 'will.' It is an instrument, the most potent man has found, whereby he brings about a harmony with his environment. This harmony is always something of a compromise. We postulate conformity between Nature and one of our ideals. We usually desire more than we can get, but insist on all that Nature can concede.

Causation serves as a good example. Experience as it first comes to us is a mere flood of happenings, with no distinction between causal and casual sequences. Clearly our whole ability to control our life, or even to continue it, demands that we should predict what happens, and guide our actions accordingly. We therefore postulate a right to dissect the flux, to fit together selected series without reference to the rest. Thus, a systematic network of natural 'laws' is slowly knit together, and chaos visibly transforms itself into scientific order. The postulation of 'causes' is verified by its success. Moreover, it is to be noted that to this postulate there is no alternative. A belief that all events are casual would be scientifically worthless. So is a doctrine (still popular among philosophers) that the only true 'cause' is the total universe at one moment, the only true 'effect,' the whole of reality at the next. For that is merely to reinstate the given chaos science tried to analyse, and to forbid us to make selections from it. It would make prediction wholly vain, and entangle truth in a totality of things which is unique at every instant, and never can recur.

The principles of mathematics are as clearly postulates. In Euclidean geometry we assume definitions of 'points,' 'lines,' 'surfaces,' etc., which are never found in nature, but form the most convenient abstractions for measuring things. Both 'space' and 'time,' as defined for mathematical purposes, are ideal constructions drawn from empirical 'space' (extension) and 'time' (succession) feelings, and purged of the subjective variations of these experiences. Nevertheless, geometry forms the handiest system for applying to experience and calculating shapes and motions. But, ideally, other systems might be used. The 'metageometries' have constructed other ideal 'spaces' out of postulates differing from Euclid's, though when applied to real space their greater complexity destroys their value. The postulatory character of the arithmetical unit is quite as clear; for, in application, we always have to agree as to what is to count as 'one'; if we agree to count apples, and count the two halves of an apple as each equalling one, we are said to be 'wrong,' though, if we were dividing the apple among two applicants, it would be quite right to treat each half as 'one' share. Again, though one penny added to another makes two, one drop of water added to another makes one, or a dozen, according as it is dropped. Common sense, therefore, admits that we may reckon variously, and that arithmetic does not apply to all things.

Again, it is impossible to concede any meaning even to the central 'law of thought' itself—the Law of Identity ('A is A')—except as a postulate. Outside of Formal Logic and lunatic asylums no one wishes to assert that 'A is A.' All significant assertion takes the form 'A is B.' But A and B are different, and, indeed, no two 'A's' are ever quite the same. Hence, when we assert either the 'identity' of 'A' in two contexts, or that of 'A' and 'B,' in 'A is B,' we are clearly ignoring differences which really exist—i.e., we postulate that in spite of these differences A and B will for our purposes behave as if they were one ('identical'). And we should realize that this postulate is of our making, and involves a risk. It may be that experience refuses to confirm it, and convicts us instead of a 'mistaken identity.' In short, every identity we reason from is made by our postulating an irrelevance of differences.

There is thus, perhaps, no fundamental procedure of thought in which we cannot trace some deliberately adopted attitude. We distinguish between 'ourselves' and the 'external' world, perhaps because we have more control over our thoughts and limbs, and less, or none, over sticks and stones and mountains; fundamental as it is, it is a distinction within experience, and is not given ready-made, but elaborated in the course of our dealings with it. Similarly, in accordance with its varying degrees of vividness, continuity, and value, experience itself gets sorted into 'realities,' 'dreams,' and 'hallucinations.' In short, when the processes of discriminating between 'dreams' and 'reality' are considered, all these distinctions will ultimately be found to be judgments of value.

Nor is it only in the realm of scientific knowing that postulation reveals itself as a practicable and successful method of anticipating experience and consolidating fact. The same method has always been employed by man in reaching out towards the final syntheses which (in imagination) complete his vision of reality. The 'truths' of all religions originate in postulates. 'Gods' and 'devils,' 'heavens' and 'hells,' are essentially demands for a moral order in experience which transcend the given. The value of the actual world is supplemented and enhanced by being conceived as projected and continued into a greater, and our postulates are verified by the salutary influence they exercise on our earthly life. Both postulation and verification, then, are applicable to the problems of religion as of science. This is the meaning of the Will to Believe. When James first defined and defended it, it provoked abundant protest, on the ground that it allowed everyone to believe whatever he pleased and to call it 'true.' The critics had simply failed to see that verification by experience is just as integral a part of voluntaristic procedure as experimental postulation, and that James himself had from the first asserted this. Indeed, that he had first given a theological illustration of the function of volition in knowing was merely an accident. But that the will to believe was capable of being generalized into a voluntarist theory of all knowledge was soon shown in Dr. Schiller's Axioms as Postulates.

CHAPTER IV