Essays in Experimental Logic

by John Dewey

II

Contemporary realists have so frequently and clearly expounded the physical explanation of such cases as have been cited that one is at a loss as to why idealists go on repeating the cases without even alluding to the realistic explanation. One is moved to wonder whether this neglect is just one of those circumstances which persistently dog philosophical discussions, or whether something in the realistic position gives ground (from at least an ad hominem point of view) for the neglect. There is a reason for adopting the latter alternative. Many realists, in offering the type of explanation adduced above, have treated the cases of seen light, doubled imagery, as perception in a way that ascribes to perception an inherent cognitive status. They have treated the perceptions as cases of knowledge, instead of as simply natural events having, in themselves (apart from a use that may be made of them), no more knowledge status or worth than, say, a shower or a fever. What I intend to show is that if "perceptions" are regarded as cases of knowledge, the gate is opened to the idealistic interpretation. The physical explanation holds of them as long as they are regarded simply as natural events—a doctrine I shall call naïve realism; it does not hold of them considered as cases of knowledge—the view I call presentative realism.

The idealists attribute to the realists the doctrine that "the perceived object is the real object." Please note the wording; it assumes that there is the real object, something which stands in a contrasting relation with objects not real or else less real. Since it is easily demonstrable that there is a numerical duplicity between the astronomical star and its effect of visible light, between the single finger and the doubled images, the latter evidently, when the former is dubbed "the" real object, stands in disparaging contrast to its reality. If it is a case of knowledge, the knowledge refers to the star; and yet not the star, but something more or less unreal (that is, if the star be "the" real object), is known.

Consider how simply the matter stands in what I have called naïve realism. The astronomical star is a real object, but not "the" real object; the visible light is another real object, found, when knowledge supervenes, to be an occurrence standing in a process continuous with the star. Since the seen light is an event within a continuous process, there is no point of view from which its "reality" contrasts with that of the star.

But suppose that the realist accepts the traditionary psychology according to which every event in the way of a perception is also a case of knowing something. Is the way out now so simple? In the case of the doubled fingers or the seen light, the thing known in perception contrasts with the physical source and cause of the knowledge. There is a numerical duplicity. Moreover the thing known by perception is by this hypothesis in relation to a knower, while the physical cause is not. Is not the most plausible account of the difference between the physical cause of the perceptive knowledge and what the latter presents precisely this latter difference—namely, presentation to a knower? If perception is a case of knowing, it must be a case of knowing the star; but since the "real" star is not known in the perception, the knowledge relation must somehow have changed the "object" into a "content." Thus when the realist conceives the perceptual occurrence as an intrinsic case of knowledge or of presentation to a mind or knower, he lets the nose of the idealist camel into the tent. He has then no great cause for surprise when the camel comes in—and devours the tent.

Perhaps it will seem as if in this last paragraph I had gone back on what I said earlier regarding the physical explanation of the difference between the visible light and the astronomical star. On the contrary, my point is that this explanation, though wholly adequate as long as we conceive the perception to be itself simply a natural event, is not at all available when we conceive it to be an attempt at knowing its cause. In the former case, we are dealing with a relation between natural events. In the latter case, we are dealing with the difference between an object as a cause of knowledge and an object as known, and hence in relation to mind. By the "method of difference" the sole explanation of the difference between the two objects is then the absence or presence of relation to a knower.

In the case of the seen light,[60] reference to the velocity of light is quite adequate to account for its time and space differences from the star. But viewed as a case of what is known (on the supposition that perception is knowing), reference to it only increases the contrast between the real object and the object known in perception. For, being just as much a part of the object that causes the perception as is the star itself, it (the velocity of light) ought logically to be part of what is known in the perception, while it is not. Since the velocity of light is a constituent element in the star, it should be known in the perception; since it is not so known, reference to it only increases the discrepancy between the object of the perception—the seen light—and the real, astronomical star. The same is true of any physical condition that might be referred to: The very things that, from the standpoint of perception as a natural event, are conditions that account for its happening are, from the standpoint of perception as a case of knowledge, part of the object which, if knowledge is to be valid, ought to be known, but is not.

In this fact we have, perhaps, the ground of the idealist's disregard of the oft-proffered physical explanation of the difference between the perceptual event and the (so-called) real object. And it is quite possible that some realists who read these lines will feel that in my last paragraphs I have been making a covert argument for idealism. Not so, I repeat; they are an argument for a truly naïve realism. The presentative realist, in his appeal to "common-sense" and the "plain man," first sophisticates the umpire and then appeals. He stops a good way short of a genuine naïveté. The plain man, for a surety, does not regard noises heard, lights seen, etc., as mental existences; but neither does he regard them as things known. That they are just things is good enough for him. That they are in relation to mind, or in relation to mind as their "knower," no more occurs to him than that they are mental. By this I mean much more than that the formulae of epistemology are foreign to him; I mean that his attitude to these things as things involves their not being in relation to him as a mind or a knower. He is in the attitude of a liker or hater, a doer or an appreciator. When he takes the attitude of a knower he begins to inquire. Once depart from thorough naïveté, and substitute for it the psychological theory that perception is a cognitive presentation to a mind of a causal object, and the first step is taken on the road which ends in an idealistic system.