21. I have already noted that sense-datum theorists are impressed by the question "How can a physical object look red to S, unless something in that situation is red and S is taking account of it? If S isn't experiencing something red, how does it happen that the physical object looks red, rather than green or streaky?" There is, I propose to show, something to this line of thought, though the story turns out to be a complicated one. And if, in the course of telling the story, I shall be led to make statements which resemble some of the things sense-datum theorists have said, this story will amount to a sense-datum theory only in a sense which robs this phrase of an entire dimension of its traditional epistemological force, a dimension which is characteristic of even such heterodox forms of sense-datum theory as the "another language" approach.

    Let me begin by formulating the question: "Is the fact that an object looks to S to be red and triangular, or that there looks to S to be a red and triangular object over there, to be explained in terms of the idea that Jones has a sensation -- or impression, or immediate experience -- of a red triangle? One point can be made right away, namely that if these expressions are so understood that, say, the immediate experience of a red triangle implies the existence of something -- not a physical object -- which is red and triangular, and if the redness which this item has is the same as the redness which the physical object looks to have, then the suggestion runs up against the objection that the redness physical objects look to have is the same as the redness physical objects actually do have, so that items which ex hypothesi are not physical objects, and which radically, even categorially, differ from physical objects, would have the same redness as physical object. And while this is, perhaps, not entirely out of the question, it certainly provides food for thought. Yet when it is claimed that "obviously" physical objects can't look red to one unless one is experiencing something that is red, is it not presumed that the redness which the something has is the redness which the physical object looks to have?

    Now there are those who would say that the question "Is the fact that an object looks red and triangular to S to be explained -- as opposed to notationally reformulated -- in terms of the idea that S has an impression of a red triangle?" simply doesn't arise, on the ground that there are perfectly sound explanations of qualitative and existential lookings which make no reference to 'immediate experiences' or other dubious entities. Thus, it is pointed out, it is perfectly proper to answer the question "Why does this object look red?" by saying "Because it is an orange object looked at in such and such circumstances." The explanation is, in principle, a good one, and is typical of the answers we make to such questions in everyday life. But because these explanations are good, it by no means follows that explanations of other kinds might not be equally good, and, perhaps, more searching.

    22. On the face of it there are at least two ways in which additional, but equally legitimate explanations might be forthcoming for such a fact as that x looks red. The first of these is suggested by a simple analogy. Might it not be the case that just as there are two kinds of good explanation of the fact that this balloon has expanded, (a) in terms of the Boyle-Charles laws which relate the empirical concepts of volume, pressure, and temperature pertaining to gases, and (b) in terms of the kinetic theory of gases; so there are two ways of explaining the fact that this object looks red to S: (a) in terms of empirical generalizations relating the colors of objects, the circumstances in which they are seen, and the colors they look to have, and (b) in terms of a theory of perception in which 'immediate experiences' play a role analogous to that of the molecules of the kinetic theory.

    Now there is such an air of paradox to the idea that 'immediate experiences' are mere theoretical entities -- entities, that is, which are postulated, along with certain fundamental principles concerning them, to explain uniformities pertaining to sense perception, as molecules, along with the principles of molecular motion, are postulated to explain the experimentally determined regularities pertaining to gases -- that I am going to lay it aside until a more propitious context of thought may make it seem relevant. Certainly, those who have thought that qualitative and existential lookings are to be explained in terms of 'immediate experiences' thought of the latter as the most untheoretical of entities, indeed, as the observables par excellence.

    Let us therefore turn to a second way in which, at least prima facie, there might be an additional, but equally legitimate explanation of existential and qualitative lookings. According to this second account, when we consider items of this kind, we find that they contain as components items which are properly referred to as, for example, 'the immediate experience of a red triangle.' Let us begin our exploration of this suggestion by taking another look at our account of existential and qualitative lookings. It will be remembered that our account of qualitative looking ran, in rough and ready terms, as follows:

'x looks red to S' has the sense of 'S has an experience which involves in a unique way the idea that x is red and involves it in such a way that if this idea were true,{7} the experience would correctly be characterized as a seeing that x is red.'

Thus, our account implies that the three situations

  1. Seeing that x, over there, is red
  2. Its looking to one that x, over there, is red
  3. Its looking to one as though there were a red object over there

differ primarily in that (a) is so formulated as to involve an endorsement of the idea that x, over there, is red, whereas in (b) this idea is only partially endorsed, and in (c) not at all. Let us refer to the idea that x, over there, is red as the common propositional content of these three situations. (This is, of course, not strictly correct, since the propositional content of (c) is existential, rather than about a presupposedly designated object x, but it will serve my purpose. Furthermore, the common propositional content of these three experiences is much more complex and determinate than is indicated by the sentence we use to describe our experience to others, and which I am using to represent it. Nevertheless it is clear that, subject to the first of these qualifications, the propositional content of these three experiences could be identical.)

    The propositional content of these three experiences is, of course, a part of that to which we are logically committed by characterizing them as situations of these three kinds. Of the remainder, as we have seen, part is a matter of the extent to which this propositional content is endorsed. It is the residue with which we are now concerned. Let us call this residue the descriptive content. I can then point out that it is implied by my account that not only the propositional content, but also the descriptive content of these three experiences may be identical. I shall suppose this to be the case, though that there must be some factual difference in the total situations is obvious.

    Now, and this is the decisive point, in characterizing these three experiences as, respectively, a seeing that x, over there, is red, its looking to one as though x, over there, were red, and its looking to one as though there were a red object over there, we do not specify this common descriptive content save indirectly, by implying that if the common propositional content were true,{8} then all these three situations would be cases of seeing that x, over there, is red. Both existential and qualitative lookings are experiences that would be seeings if their propositional contents were true.

    Thus, the very nature of "looks talk" is such as to raise questions to which it gives no answer: What is the intrinsic character of the common descriptive content of these three experiences? and How are they able to have it in spite of the fact that whereas in the case of (a) the perceiver must be in the presence of a red object over there, in (b) the object over there need not be red, while in (c) there need be no object over there at all?

    23. Now it is clear that if we were required to give a more direct characterization of the common descriptive content of these experiences, we would begin by trying to do so in terms of the quality red. Yet, as I have already pointed out, we can scarcely say that this descriptive content is itself something red unless we can pry the term "red" loose from its prima-facie tie with the category of physical objects. And there is a line of thought which has been one of the standard gambits of perceptual epistemology and which seems to promise exactly this. If successful, it would convince us that redness -- in the most basic sense of this term -- is a characteristic of items of the sort we have been calling sense contents. It runs as follows:

While it would, indeed, be a howler to say that we don't see chairs, tables, etc., but only their facing surfaces, nevertheless, although we see a table, say, and although the table has a back as well as a front, we do not see the back of the table as we see its front. Again, although we see the table, and although the table has an 'inside,' we do not see the inside of the table as we see its facing outside. Seeing an object entails seeing its facing surface. If we are seeing that an object is red, this entails seeing that its facing surface is red. A red surface is a two-dimensional red expanse -- two-dimensional in that though it may be bulgy, and in this sense three-dimensional, it has no thickness. As far as the analysis of perceptual consciousness is concerned, a red physical object is one that has a red expanse as its surface.

    Now a red expanse is not a physical object, nor does the existence of a red expanse entail the existence of a physical object to which it belongs. (Indeed, there are "wild" expanses which do not belong to any physical object.) The "descriptive content" -- as you put it -- which is common to the three experiences (a), (b) and (c) above, is exactly this sort of thing, a bulgy red expanse.

    Spelled out thus baldly, the fallacy is, or should be, obvious; it is a simple equivocation on the phrase "having a red surface." We start out by thinking of the familiar fact that a physical object may be of one color "on the surface" and of another color "inside." We may express this by saving that, for example, the 'surface' of the object is red. but its 'inside' green. But in saying this we are not saying that there is a 'surface' in the sense of a bulgy two-dimensional particular, a red 'expanse' which is a component particular in a complex particular which also includes green particulars. The notion of two-dimensional bulgy (or flat) particulars is a product of philosophical (and mathematical) sophistication which can be related to our ordinary conceptual framework, but does not belong in an analysis of it. I think that in its place it has an important contribution to make. (See below, Section 61, (5)) But this place is in the logical space of an ideal scientific picture of the world and not in the logical space of ordinary discourse. It has nothing to do with the logical grammar of our ordinary color words. It is just a mistake to suppose that as the word "red" is actually used, it is ever surfaces in the sense of two-dimensional particulars which are red. The only particular involved when a physical object is "red on the outside, but green inside" is the physical object itself, located in a certain region of Space and enduring over a stretch of Time. The fundamental grammar of the attribute red is physical object x is red at place p and at time t. Certainly, when we say of an object that it is red, we commit ourselves to no more than that it is red "at the surface." And sometimes it is red at the surface by having what we would not hesitate to call a "part" which is red through and through -- thus, a red table which is red by virtue of a layer of red paint. But the red paint is not itself red by virtue of a component -- a 'surface' or 'expanse'; a particular with no thickness -- which is red. There may, let me repeat, turn out to be some place in the total philosophical picture for the statement that there "really are" such particulars, and that they are elements in perceptual experience. But this place is not to be found by an analysis of ordinary perceptual discourse, any more than Minkowski four-dimensional Space-Time worms are an analysis of what we mean when we speak of physical objects in Space and Time.