XI
THE EXISTENCE OF THE WORLD AS A LOGICAL PROBLEM
Of the two parts of this paper the first is a study in formal analysis. It attempts to show that there is no problem, logically speaking, of the existence of an external world. Its point is to show that the very attempt to state the problem involves a self-contradiction: that the terms cannot be stated so as to generate a problem without assuming what is professedly brought into question. The second part is a summary endeavor to state the actual question which has given rise to the unreal problem and the conditions which have led to its being misconstrued. So far as subject-matter is concerned, it supplements the first part; but the argument of the first part in no way depends upon anything said in the second. The latter may be false and its falsity have no implications for the first.
I
There are many ways of stating the problem of the existence of an external world. I shall make that of Mr. Bertrand Russell the basis of my examinations, as it is set forth in his recent book Our Knowledge of the External World as a Field for Scientific Method in Philosophy. I do this both because his statement is one recently made in a book of commanding importance, and because it seems to me to be a more careful statement than most of those in vogue. If my point can be made out for his statement, it will apply, a fortiori, to other statements. Even if there be those to whom this does not seem to be the case, it will be admitted that my analysis must begin somewhere. I cannot take the space to repeat the analysis in application to differing modes of statement with a view to showing that the method employed will yield like results in all cases. But I take the liberty of throwing the burden upon the reader and asking him to show cause why it does not so apply.
After rejecting certain familiar formulations of the question because they employ the not easily definable notions of the self and independence, Mr. Russell makes the following formulation: Can we "know that objects of sense ... exist at times when we are not perceiving them?" (op. cit., p. 75). Or, in another mode of statement: "Can the existence of anything other than our own[63] hard data be inferred from the existence of those data?" (pp. 73 and 83).
I shall try to show that identification of the "data of sense" as the sort of term which will generate the problem involves an affirmative answer to the question—that it must have been answered in the affirmative before the question can be asked. And this, I take it, is to say that it is not a question at all. A point of departure may be found in the following passage: "I think it must be admitted as probable that the immediate objects of sense depend for their existence upon physiological conditions in ourselves, and that, for example, the colored surfaces which we see cease to exist when we shut our eyes" (p. 64). I have not quoted the passage for the sake of gaining an easy victory by pointing out that this statement involves the existence of physiological conditions. For Mr. Russell himself affirms that fact. As he points out, such arguments assume precisely the "common sense world of stable objects" professedly put in doubt (p. 85). My purpose is to ask what justification there is for calling immediate data "objects of sense." Statements of this type always call color visual, sound auditory, and so on. If it were merely a matter of making certain admissions for the sake of being able to play a certain game, there would be no objection. But if we are concerned with a matter of serious analysis, one is bound to ask, Whence come these adjectives? That color is visual in the sense of being an object of vision is certainly admitted in the common-sense world, but this is the world we have left. That color is visual is a proposition about color and it is a proposition which color itself does not utter. Visible or visual color is already a "synthetic" proposition, not a term nor an analysis of a single term. That color is seen, or is visible, I do not call in question; but I insist that fact already assumes an answer to the question which Mr. Russell has put. It presupposes existence beyond the color itself. To call the color a "sensory" object involves another assumption of the same kind but even more complex—involving, that is, even more existence beyond the color.
I see no reply to this statement except to urge that the terms "visual" and "sensory" as applied to the object are pieces of verbal supererogation having no force in the statement. This supposititious answer brings the matter to a focus. Is it possible to institute even a preliminary disparaging contrast between immediate objects and a world external to them unless the term "sensory" has a definite effect upon the meaning assigned to immediate data or objects? Before taking up this question I shall, however, call attention to another implication of the passage quoted. It appears to be implied that existence of color and "being seen" are equivalent terms. At all events, in similar arguments the identification is frequently made. But by description all that is required for the existence of color is certain physiological conditions. They may be present and color exist and yet not be seen. Things constantly act upon the optical apparatus in a way which fulfils the conditions of the existence of color without color being seen. This statement does not involve any dubious psychology about an act of attention. I only mean that the argument implies over and above the existence of color something called seeing or perceiving—noting is perhaps a convenient neutral term. And this clearly involves an assumption of something beyond the existence of the datum—and this datum is by definition an external world. Without this assumption the term "immediate" could not be introduced. Is the object immediate or is it the object of an immediate noting? If the latter, then the hard datum already stands in connection with something beyond itself.
And this brings us to a further point. The sense objects are repeatedly spoken of as "known." For example: "It is obvious that since the senses give knowledge of the latter kind [believed on their own account, without the support of any outside evidence] the immediate facts perceived by sight or touch or hearing do not need to be proved by argument but are completely self-evident" (p. 68). Again, they are spoken of as "facts of sense"[64] (p. 70), and as facts going along, for knowledge, with the laws of logic (p. 72). I do not know what belief or knowledge means here: nor do I understand what is meant by a fact being evidence for itself.[65] But obviously Mr. Russell knows, and knows their application to the sense object. And here is a further assumption of what, by definition, is a world external to the datum. Again, we have assumed in getting a question stated just what is professedly called into question. And the assumption is not made the less simple in that Mr. Russell has defined belief as a case of a triadic relation, and said that without the recognition of the three-term relation the difference between perception and belief is inexplicable (p. 50).