SENSE DATA AND THE PERCEPT THEORY

Roderick Firth, Sense Data and the Percept Theory, 1949-50.

2. THE PHYSICAL OBJECT AND THE OSTENSIBLE PHYSICAL OBJECT

Assuming, then, that there are at least three senses in which the distinction between the given and its interpretation may be recognised by those who accept the Percept Theory, and that there is only one traditional sense in which this distinction must be denied, we are now in a position to consider some of the epistemological questions raised by the statement that physical objects are directly given in perception. This statement, as we have seen, has been made repeatedly in recent years by supporters of the Percept Theory, and in one natural interpretation its implications are indeed revolutionary, and probably incredible; I presume, in fact, that many epistemologists have dismissed it without further ado on the assumption that it is based on a simple confusion of physical objects with ostensible physical objects. But the issue is much more complex than such an explanation would suggest.

(a) The Epistemological Status of Ostensible Properties
If any of the philosophers who have said that physical objects are directly given in perception have simply failed to recognise the difference between a physical object and an ostensible physical object, then they have, of course, committed a fallacy of some magnitude. To demonstrate this fact with thoroughness by making an exhaustive catalogue of the common properties of physical objects, would lead us into metaphysical questions which are beyond the scope of this paper; and even an attempt at this point to find a minimum basis of agreement concerning the correct analysis of the term "physical", would distract attention from the principal issue. But anyone who accepts the Percept Theory must admit that there is at least one important fact about an ostensible physical object which serves to distinguish it sharply from a physical object -- the fact, namely, that some of its properties, if not all, can be discovered by direct inspection of a single state of perceptual consciosness.⁶⁴ Whether this is taken to be an epistemological fact or an ontological fact or both, will depend on one's general theory of the mind, but it is a fact which cannot be denied by those who accept the Percept Theory without rejecting the method of direct inspection and thus the very evidence on which that theory is based.
It is equally certain, on the other hand, that whatever we may mean by "physical object", a physical object is at the very least a thing which transcends any one of the states which might be called a perception of it. This is admitted, of course, even by Berkeley an contemporary realists who have defended various forms of epistemological monism; none of them, so far as I know, has maintained that to attribute a property to a physical object is merely to attribute that property to what is presented in some one state of perceptual consciousness. In order to confirm a statement about a physical object we may indeed require the information that can be obtained by direct inspection of a state of perception, but we also require other information -- information, for example, about the relationship between this particular state of perception and other experiences, either actual or possible. And if this point is obvious to those who defend epistemological monism, it is undoubtedly still more obvious to those who accept some form of epistemological dualism. Whether, therefore, our general concept of physical object is in some sense "derived from" the presentation of ostensible physical objects in perception, or whether it is in one or another sense "a priori", the indisputable fact remains that we do possess two concepts corresponding to the terms "physical object" and "ostensible physical object". And the difference between these two concepts is sufficiently proved, for present purposes, by the fact that properties of ostensible physical objects can be discovered by direct inspection of a single state of perceptual consciousness, whereas properties of physical objects cannot.
The fact that the properties of these two kinds of object are designated by the same names, should not be allowed to obscure this difference in the epistemological (and, for most philosophers, the ontological) status of the properties. There is, of course, some relationship between the properties of physical objects and the properties of ostensible physical objects which accounts for the fact that the word "square", for example, which designates a property of physical objects, is also used to designate a certain property of ostensible physical objects. Philosophers disagree, of course, about the nature of this relationship, just as they disagree about the number of words in our language which can properly be used in both the phenomenal and physical contexts. But they all agree, so far as I know, that a distinction may be made between the phenomenal use and the physical use of certain adjectives, and that this distinction reflects an important difference in the status of the designated properties.

(b) The Ostensible Physical Object and Naive Realism
Now although it is very unlikely that a philosopher who asserts that physical or material objects are given in perception has committed the fallacy of confusing his concept of a physical object with his concept of an ostensible physical object, it is a good deal more likely that he has committed a fallacy somewhat similar to this. For he may have assumed that there is no difference at all between his own concept of an ostensible physical object and the naive or popular concept of a "real" physical object. He may believe, in other words, that what the man in the street means when he says that the paving stones are grey, is precisely what he, the philosopher, would mean if he said that the ostensible paving stones are grey. This possibility is suggested by the frequency with which advocates of the Percept Theory describe that which is given in perception as a "naive world", a "pre-philosophical world", a common-sense realistic world", etc. And it might help to explain, at least in some cases, what is meant by the statement that physical objects are given. For if the concept of an ostensible physical object were identified with the naive concept of a physical object, such a statement would mean simply that physical objects, in the popular sense of the word "physical", are the directly presented objects of consciousness in ordinary perceptual experience.
If such a statement is made by a philosopher who accepts the Percept Theory, and is intended to express one of the important implications of that theory, it cannot be lightly dismissed as true in any trivial sense. There are some possible interpretations of the word "given", of course, according to which it may be quite obviously true that physical objects, as popularly conceived, are given to the man in the street during perceptual experience. Thus it is not unlikely that there is some sense of the verb "to believe" such that the man in the street may correctly be said to believe, whenever he is perceptually conscious, that there exists a physical object of a certain kind; and the word "given" might accordingly be interpreted to mean "believed to exist". This cannot be the interpretation desired by supporters of the Percept Theory, however, for the Percept Theory, as we have seen, is a theory about the sensuous aspects of perceptual consciousness, and not about the beliefs which may accompany the presentation of an ostensible physical object. Indeed the obvious fact that the man in the street has perceptual beliefs about physical objects, is quite compatible with the rival Sense-datum Theory, whereas the statement that physical objects are given in perception is intended to be a criticism of that theory.
The question which now confronts us, therefore, is whether there is any reason to believe that the sensuous objects of perceptual consciousness (i.e., ostensible physical objects) are precisely what the man in the street thinks of as "real" physical objects. It is usually true, of course, that at the moment of ordinary perception the man in the street does not consciously judge that the ostensible physical object is not a "real" physical object, but for that matter neither does the philosopher. Nor, on the other hand, is it plausible to maintain that either of them at the moment of perception, consciously judges that the two objects are identical. Ordinary perception is simply not reflective in a sense which would permit either of these two conscious judgements, whether or not the necessary concepts are somehow available. The fact that the philosopher possesses two distinct concepts corresponding to the terms "physical object" and "ostensible physical object", is proved by his ability to distinguish them on reflexion; if an advocate of the Percept Theory wishes to show, therefore, that the man in the street does not possess two such concepts, he must do so by proving that the man in the street cannot distinguish them on reflexion.
When the issue is stated in these terms, however, it becomes quite clear that however naive the man in the street may be, his naivete does not consist in his failure to possess some concept of a physical object as distinguished from an ostensible physical object. To deny this, indeed, would be to deny that he possesses any concept of "illusion", and to imply, therefore, that he is a naive realist of a type incapable of understanding, even in some "popular" sense, what it means to say that an oar looks bent but is really straight. And perhaps it would be relevant to point out that the man in the street is usually credited with much more sophistication than this; many philosophers ranging from Berkeley to certain contemporary realists have professed to speak for him, and although they cannot all have described his views correctly in every respect, they have all agreed in constructing epistemological theories which admit the possibility of illusion. To possess the concept of illusion, however, is to recognise, at least implicitly, the very difference between a physical object and an ostensible physical object which would be most likely to impress a supporter of the Percept Theory -- the difference, namely, which is reflected in the fact that the properties of physical objects, unlike those of ostensible physical objects, cannot be discovered be direct inspection of a single state of perceptual consciousness.
It would be a mistake, therefore, to say that physical objects are given in perception, if the purpose of this form of expression were to imply that when the man in the street says that the paving stones are grey he is talking about what the philosopher would call ostensible paving stones. It might seem important to point out that there is some similarity between an ostensible physical object and a "real" physical object as popularly conceived -- that words which refer to the so-called "secondary" qualities, for example, can be used to describe both of them -- but it would surely be misleading to express this fact by saying that physical objects are given. There seems, therefore, to be no purely semantical fact about the meaning of the terms "physical object" and "ostensible physical object", which could justify the statement that physical objects are given in perception. There is, however, a phenomenological fact which might make such a form of expression seem appropriate to some advocates of the Percept Theory. Let us consider it briefly.

(c) The Ostensible v. the Apparently Ostensible
This phenomenological fact is the one suggested by Dewey's statement that "it is not experience which is experienced, but nature", the fact, namely, that ostensible physical objects, as presented to us in perception, do not ordinarily appear ostensible. Or, to put the matter in a way which emphasises the linguistic difficulties which are always implicit in such discussions as this, ostensible physical objects are not ostensibly ostensible. The object of which we are conscious in perception, as Price has so aptly said, "just dawns upon us, of itself. We look and there it is."⁶⁵ Thus a tomato is perceptually presented as red, as solid, and perhaps even as edible, but it is not presented as ostensible. Nor, on the other hand, is it presented as non-ostensible. The terms "ostensible" and "non-ostensible" both refer to epistemological or ontological characteristics, and are properly applied to an entity, as we have seen, after considering such matters as its accessibility to direct inspection; they are not phenomenal qualities which ostensible physical objects wear on their faces.⁶⁶
It ls difficult to find a terminology which will keep this distinction from becoming obscured, and which will at the same time be convenient for the discussion of problems which have both phenomenological and epistemological facets. Thus although it has been convenient, and I hope not misleading, to say that we are presented in perception with ostensible physical objects, even such a statement is not unambiguous. In a purely phenomenological context the word "ostensible" would have to be omitted from this statement, since otherwise it could be interpreted as implying that ostensibility is one of the presented characteristics of the object. And questions could also be raised about the word "physical" (or any substitute such as the word "material") for this too, as we have just observed, has epistemological and ontological connotations. But the full force of the difficulty is not felt until we try to dispense with the word "physical" and say instead simply that the objects presented in perception are solid and three-dimensional, persisting through time, possessing causal characteristics, etc. For it will then become evident that each one of these descriptive terms also has epistemological and ontological connotations. We have already seen that such terms, when used to describe physical objects, designate properties the existence of which cannot be determined by direct inspection of a single state of perceptual consciousness, and we surely do not want to suggest that in perception we are presented with properties of this kind. The pervasiveness of this terminological difficulty, as we have also seen, is a result of the fact that in a phenomenological context most, and perhaps all, of the adjectives in our language have a meaning which they could not possibly have if they were being used to describe physical objects.
It is possible, therefore, that the philosophers who have maintained, on the basis of the Percept Theory, that physical objects are actually given in perception, have used this form of expression in an attempt to solve, at least partially, the terminological problem just outlined. This form of expression, as we have seen, does not by any means solve the entire problem, but it might help to emphasise the fact that the objects which are presented in perception are not presented as ostensible. And some advocates of the Percept Theory have thought it important to emphasise this fact because the failure of epistemologists to recognise it may have been responsible for the generation of "pseudo-problerns".⁶⁷ Similarly, the statement that in perception we are "directly aware" of physical or material objects, which is often made by the same philosophers, can perhaps be accounted for as an alternative method of emphasising the same phenomenological fact. Indeed neither of these two forms of expression seems entirely inappropriate when considered in this light, although they may have been the cause, because of their traditional epistemological connotations, of more misunderstanding than they have prevented.
However this may be decided, the issues to be discussed in the following pages are primarily epistemological; and it is consequently impossible to restrict ourselves to forms of expression which would be appropriate in a purely phenomenological context. I shall continue to say, therefore, that the objects directly presented or given in perception are ostensible physical objects, recognising, however, that I can say this only because I am not attempting merely to describe the phenomenal properties of the objects of perceptual consciousness -- only, in short because I l have adopted the epistemological point of view. From this point of view it is clear that physical objects, because they are things the properties of which cannot be discovered by direct inspection of a single state of perceptual consciousness, cannot reasonably be said to be "directly presented" or "given" in such a state of perceptual consciousness.
In this particular respect, of course, the distinction between an ostensible physical object and a physical object is strictly parallel to one of the most important of the traditional distinctions between a sense-datum and a physical object; for sense-data have traditionally been conceived as observable by direct inspection, and physical objects as knowable only through some more complex process. In fact it should now be clear that the concepts of physical object and ostensible physical obiect are so independent of one another, from a logical point of view, that the basic distinctions will not be affected by the outcome of the conflict between the Percept Theory and the Sense-datum Theory. The questions which remain to be answered therefore, in any attempt to evaluate the epistemological implications of the Percept Theory, are questions about the epistemological functions of ostensible physical objects; and the most direct way to raise these questions is to ask whether ostensible physical objects are adequate substitutes for performing the functions which sense-data have traditionally been supposed to perform in the processes by which we acquire and confirm our beliefs about the physical world.

Contents -- Next

Notes
⁶⁴ I say "some" because it is possible that a philosopher who accepts the Percept Theory might agree with Broad that things which are present to consciousness "cannot appear to have properties which they do not really have, though there is no reason why they should not have more properties than we do or can notice". Scientific Thought, pp. 243-244.
⁶⁵ Perception, p. 153.
⁶⁶ It might be argued that an oasis may appear ostensible to an experienced desert traveller who knows that he is experiencing a mirage. But in that case the word "ostensible" has a phenomenal significance which could be absorbed by the statement that the traveller perceives a mirage of an oasis.
⁶⁷ See e.g., K. Duncker, "Phenomenology and Epistemology of Consciousness", Philosophy and Phenomenological Research, June, 1947. I believe that Duncker is clearly mistaken, however, if he intends to imply that there is no genuine problem concerning the possibility of transcending consciousness.
Contents -- Next