"If the truth of a cognition were self apprehended, then in regard to a cognition at the non-recurrence stage there would not be doubt. For then, if the cognition is cognized, its validity also is cognized, while if the cognition is not cognized, then, as the thing to be doubted is not cognized. how can there be doubt? Hence the validity of a cognition is matter of inference. Thus: This cognition is truth,

6

because it gives rise to accordant response; what is not so, does not do so.' This cognition having the determination 'earth-ness' is truth, because it is cognition with determination earthness' applied to what has odour. Nor should it be asked whence comes the cognition of the middle. For the having the determination earthness' is self-apprehended, and, as odour is apprehended of that, the application to the thing having odour is obvious. Nor should it be asked how the major being truth,' is known beforehand; for in the cognition 'this' a being truth is self-apprehended."

As regards the regressus ad infinitum it is observed that we come sooner or later to a certitude of which invalidity is not apprehended; we do not entertain doubt of everything and that is enough. Accordingly the view is that validity is matter for inference, that we go back as far as there is doubt, and that ultimately there are cognitions, such as the cognition this," of which the truth is self-evident.

On the whole it would appear that in the view of all these disputants there is a stage (in the Nyaya-Vaiseshika system the “unquestioning ") in perception which is not susceptible of error. They differ as to its character and discuss whether it is known to consciousness and in what manner error creeps in. In cases such as that of the distant "stump" or man" some admitted a perceptual doubt, just as in the case of conflicting middles some posited an “inference of doubt." But the Nyaya denies that the "apparatus of doubt" exists prior to the

perceptual judgment; and clearly perceptual doubt must be due to imperfection somewhere, unless we are prepared to admit the actual existence of "doubtful" objects which can develop upon inspection into either "posts" or "men."

The scholastic character of these discussions is apparent. What I should like to inquire of the Aristotelian Society is how far they bear upon the real problems. It seems that modern psychology admits in perception a large representational element. If I take for a horse something in the distance which turns out to be a cow, presumably the "horse" part is representational. But much more is ultimately representational and the ultimate presentational element may be merely a dark patch in a field. Apparently every element may be illusory, and more particularly the last, which may be a spot on the eye or some defect in the visual apparatus. If truth of perception were normality with reference either to the individual or the race or (by aid of a proportion) to all percipients, then normal illusions would be true (perhaps they are ?); while, if it is verification, the "seeing of more parts" and so on, the process may require an indefinite stretch of time, in some cases ages, and truth becomes relative or an ideal, although through seeing of a differentia" many errors may successively receive their quietus. However, verification, combined with the notion of a content, seems to imply something more than consistency of appearances; for, if the awareness is a simple factor, invariant in all the appearances, the consistency must be on the side of the content, and this consistency would signify a "being" in the thing.

Meeting of the Aristotelian Society at 21, Gower Street, W.C. 1,

on December 5th, 1921, at 8 P.M.

III-ON THE LIMITATIONS OF A KNOWLEDGE OF NATURE.

By JAMES JOHNSTONE.

SOMETIME about the beginning of the eighteenth century, and during the last ten years of his lifetime, Newton spoke to a friend about his work: "I know not," he said, "how it may seem to the world but, as to myself, I seem to have been only as a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me." These words, I take it, were, in a way, an admission of cessation of individual effort. By reason of his resolute and disciplined imagination, his genius for experiment and the mighty mathematical weapons that he had made, Newton had found a way. He thought about truth as lying there, spread out, so to speak, and waiting to be discovered and the means whereby that discovery was to be made were known to him. He knew that what he had found was only an infinitesimal part of all that was accessible by application of his methods. But there is only so much dynamic mental quality in any man, a little more or a little less as we vary from each other, and this can be "intended" to the investigation of nature, the pursuit of pleasure or the acquisition of wealth, and it can be exhausted. In little over forty years Newton, like his great predecessor, Descartes, had spent his creative energy, and the undiscovered, but discoverable ocean of truth was still there.

By the time that these words were spoken the course that physical and natural science was to follow during the next century and half had already been marked out by three great men: Galileo, to an extent which has only been appreciated by

F

some of us as the result of the relativity discussions of the last few years; Descartes, by the exercise of an "inventiveness" which, as Clerk Maxwell said, "knew no bounds"; and Newton himself, who had found the way. Throughout that century and half one seems to trace little or no really creative scientific thought but only a successful working out of the great ideas of the seventeenth century. From these came our conceptions of matter, inertia and force; the laws of motion; the theory of universal gravitation; the description of the Solar system; the notion of the ether as the locus and substance of physical change; the ideas of illimitable space and uniformly flowing infinite time; the Cartesian mechanism of life and the restricted theory of relativity. About the middle of the nineteenth century new ideas did come: perhaps the notion of natural selection was really new--I do not know-perhaps we had in that idea, the first clear distinction between statistical and individual results-a distinction that does not yet seem fully to be realized and employed in biological science. And then, a little later, we had from the mathematical investigators, of whom J. Clerk Maxwell is the type, the germinal work that was to bring about a revolution in knowledge.

Throughout those two centuries scientific men employed the inventions of Galileo, Descartes and Newton. Physics and natural science (which has always clung to the skirts of physics) explored the seashore, described and catalogued the pebbles and shells and now and then ventured out on the ocean. The eighteenth and nineteenth centuries elaborated the methods of the seventeenth, employing them in ways that were certainly unanticipated by Descartes and Newtonone wonders what the great French philosopher would have thought about the modern mechanistic conception of life, as it has been stated by Jacques Loeb! It has been noted that as the methods of the seventeenth century became exhausted so did the materialistic science of the nineteenth seem to approach

finality and tend to become complete and rounded-off, in a sense. Perhaps one may be quite wrong but it does appear as if the natural science of the latter third of the last century regarded its framework as sound and entirely satisfactory and one gets suggestions of that kind from some of Huxley's essays. What was the good of quarrelling about the unknowable? The speculative game was drawn and what was left for Science was the work of strengthening the framework and filling in the details.

Perhaps this hard nineteenth century materialism had its work to do in the evolution of social and political liberty. It had to assert itself as a way of interpreting the meaning of the passage of nature" and of searching out the origin and destiny of man. Medieval doctrines of social and economic privilege had to be destroyed. Perhaps that work is not yet fully accomplished and while that is so science will remain materialistic. There is still a fraudulent and grotesque spiritualism to be detected; a muddled vitalism to be replaced by something sounder and a prematurely formulated Eugenics," that may be utilized to maintain caste and social disability, to be sifted clear from humbug. We may leave materialistic biology to these tasks.

Two centuries later than Newton a modern thinker,* writing while a revolution in scientific thought was being effected, refers to "the passage of nature which is only another name for the creative force of existence." "This operative presence" he says, "which is now urging nature forward must be sought for throughout the whole, in the remotest past as well as in the narrowest breadth of any present duration. Perhaps also in the unrealized future. Perhaps also in the future which might be, as well as in the future which will be. It is impossible to

* A. N. Whitehead, in The Concept of Nature, Cambridge University Press, 1920, p. 73.