Further, we come here to what for the purpose of our present argument is the most important consideration of all, viz. that if we could show that there were two kinds of neural or physiological processess, occurring respectively on all occasions of pleasure and pain, the fact would be valueless for proving that life must be predominantly pleasant. It is perhaps intelligible that to succeed or fail in purposive activity should bring respectively contentment and discontent rather than vice-versa; but that of two kinds of neural or physiological process, one should be accompanied by pleasure and the other by pain, is no more intelligible than if the connection were reversed. If the behaviour of any creature is affected by desires and aversions, by judgments, by feelings: if its desires and aversions or its judgments are connected with or affected by its pleasures and pains, then indeed the question with what bodily conditions its pleasures and pains are connected is part of the problem that interests the biologist—viz. what the conditions are under which the species can continue. But in that case the biologist must not claim that all the conditons of life and reproduction can be found in what happens in the body. Pleasures and pains, desires and aversions, purposes are not events that happen in the body. If they are the mere “apparence or sense” of what happens there, and alone determines survival or extinction, then what happens there to determine survival might, for all we can see, equally appear as pain or pleasure.

This paper is an attempt to clarify our talk about minds and thoughts—our own minds and the thoughts which run through them and which we know directly, as well as the minds of other people and the thoughts with which we credit them. We do so in order to be able to characterize satisfactorily our whole performance in talking about minds and thoughts, the rules according to which such talk operates and the goals it purports to reach. We also hope to evaluate, in the light of such a characterization, a number of more elaborate ways of speaking about minds and thoughts, so as to become clear as to their advantages or disadvantages in comparison with more ordinary ways of speaking. The whole investigation is well worth undertaking, since it has long been evident that our talk about mind and thought is, to a peculiar extent, liable to become the seat of certain deep perplexities, which do not arise when we deal with unusual material on the borderlines of knowledge, but which tend, rather, to obtrude themselves in commonplace situations, and to trouble our grasp of the most obvious notions and the most evident truths. Such perplexities, broadly covered by the word “philosophical,” are rendered very stubborn by their objects and their origin. For when we are dealing with things remote, strange and intricate, we have at least a firm foothold in the well-known, simple and near, and a clear set of terms to talk with; but we hardly seem to have a perch to hop to, or any intelligible language left to talk in, when the obvious itself begins to present difficulties. And it is also characteristic of most of the difficulties we are considering that in them the burning zone of perplexity seems to shift erratically from issue to issue, that each expedient adopted to meet them involves us in new problems, that men cannot ever agree as to the best expedient or the least serious difficulty, and that, in the outcome, they resemble nothing so much as a set of sleepers under inadequate coverings, some of whom prefer exposure in one place, while others prefer it in another.

Prima facie knowledge is an ineradicable monster. Conceived as a relation of a mind to objects extrinsic to it, it is chimerical: for knowledge, as such, is of the real, i.e. of things as they are in se; but the prima facie form of knowledge precludes this. Its object is a thing apprehended ab extra, i.e. as referred to a subject to which it is extrinsic. To seek to escape this impasse either by making the object intrinsic to the subject, or the subject a function of the object, is to reject the prima facie character of knowledge as a relation of compresent terms. The incoherence of prima facie knowledge is that its object must be both extrinsic and intrinsic to mind—extrinsic as independently real, intrinsic as known—yet can be neither: not extrinsic since thus its inseitas is occulted, not intrinsic since thus truth is mere appearance. And this chimaera becomes a monster because knowledge is also ineradicable. We cannot know that knowledge is impossible; and, though we may be in doubt about its extancy, that very doubt is epistemic in form. It is our acceptance of the demands of knowledge that lies at the basis of our doubt; and this applies not only to legitimate doubt about the extancy of knowledge, but also to chimerical doubt about its possibility. Doubt is an inchoation of knowledge, which is thus ineradicable.

A young boy found one of Beck's best stereoscopes, but he did not understand its use. When he looked through the two eye-pieces at the two adjacent duplicates (nearly) of each picture on each card he got a single flat picture, and he expected nothing more. Then the moment of revelation came. As he fumbled the focus onto a flat picture of Hamlet, the grave-diggers and Hamlet himself bulged out, the skull on Hamlet's palm looked like a museum piece, and the grave yawned like a real pit. The stereoscopic world of the Beck instrument had been suddenly established in the boy's experience.