It is scarcely necessary in view of the foregoing to add that the data of science are not "sense-data," if by sense-data be meant data which are the result of the operations of sense organs alone. Data are as much or more the result of operations, first, of the motor system of the scientist's own organism, and second, of all of the machinery of his laboratory which he calls to his aid. Whether named after the way they are obtained, or after the way they are used, data are quite as much "motor" as "sense." Nor, on the other hand, are there any purely intellectual data—not even for the mathematician. Some mathematicians may insist that their symbols and diagrams are merely stimuli to the platonic operation of pure and given universals. But until mathematics can get on without these symbols or any substitutes the intuitionist in mathematics will continue to have his say.
Wherever the discontinuity between logical operations and their acts persists, all the difficulties with data have their correlative difficulties with hypotheses. In Mill's logic the account of the origin of hypotheses oscillates between the view that they are happy guesses of a mind composed of states of consciousness, and the view that they are "found in the facts" or are "impressed on the mind by the facts." The miracle of relevancy required in the first position drives the theory to the second. And the tautologous, useless nature of the hypothesis in the second forces the theory back to the first view. In this predicament, little wonder Mill finds that the easiest way out is to make hypotheses "auxiliary" and not indigenous to inference. But this exclusion of hypotheses as essential leaves his account of inference to oscillate between the association of particulars of nominalism and scholastic formalism, from both of which Mill, with the dignified zeal of a prophet, set out to rescue logic.
Mill's rejection of hypotheses formed by a mind whose operations have no discoverable continuity with the operations of things, or by things whose actions are independent of the operations of ideas, is forever sound. But his acceptance of the discontinuity between the acts of knowing and the operation of things, and the conclusion that these two conceptions of the origin and nature of hypotheses are the only alternatives, were the source of most of his difficulties.
III
The efforts of classic empiricism at the reform of logic have long been an easy mark for idealistic reformers. But it is interesting to observe that the idealistic logic from the beginning finds itself in precisely the same predicament regarding hypotheses;—they are trifling or false. And in the end they are made, as in Mill, "accidents" of inference.
The part played by Kant's sense-material and the categories is almost the reverse of those of data and hypothesis in science. Sense material and the categories are the given elements from which objects are somehow made; in scientific procedure data and hypothesis are derived through logical observation and imagination from the content and operations of immediate experience. In Kant's account of the process by which objects are constructed we are nowhere in sight of any experimental procedure. Indeed, the real act of knowing, the selection and application of the category to the sense matter, is, as Kant in the end had to confess, "hidden away in the depths of the soul." Made in the presence of the elaborate machinery of knowing which Kant had constructed, this confession is almost tragic; and the tragic aspect grows when we find that the result of the "hidden" operation is merely a phenomenal object. That this should be the case, however, is not strange. A phenomenal object is the inevitable correlate of the "hidden" act of knowing whether in a "transcendental" or in an "empirical" logic. In vain do we call the act of knowing "constructive" and "synthetic" if its method of synthesis is hidden. A transcendental unity whose method is indefinable has no advantage over empirical association.
It was the dream of Kant as of Mill to replace the logics of sensationalism and rationalism with a "logic of things" and of "truth." But as Mill's things turned to states of consciousness, so Kant's are phenomenal. Their common fate proclaims their common failure—the failure to reëstablish continuity between the conduct of intelligence and other conduct.
One of the chief counts in Hegel's indictment of Kant's logic is that "it had no influence on the methods of science."[15] Hegel's explanation is that Kant's categories have no genesis; they are not constructed in and as part of logical operations. As given, ready-made, their relevance is a miracle. But if categories be "generated" in the process of knowing, says Hegel, they are indigenous, and their fitness is inevitable. In such statements Hegel raises expectations that we are at last to have a logic which squares with the procedure of science. But when we discover that instead of being "generated" out of all the material involved in the scientific problem Hegel's categories are derived from each other, misgivings arise. And when we further learn that this "genesis" is timeless, which means that, after all, the categories stand related to each other in a closed, eternal system of implication, we abandon hope of a scientific—i.e., experimental—logic.
Hegel also says it is the business of philosophy "to substitute categories or in more precise language adequate notions for the several modes of feeling, perception, desire, and will." The word "substitute" reveals the point at issue. If "to substitute" means that philosophy is a complete exchange of the modes of feeling, perception, desire, and will for a world of categories or notions, then, saying nothing of the range of values in such a world, the problem of the meaning of "adequate" is on our hands. What is the notion to be adequate to? But if "to substitute" means that the modes of feeling, perception, desire, and will, when in a specific situation of ambiguity and inhibition, go over into, take on, the modes of data and hypothesis in the effort to get rid of inhibiting conflict that is quite another matter. Here the "notion," as the scientific hypothesis, has a criterion for its adequacy. But if the notion usurps the place of feeling, perception, desire, and will, as many find, in the end, it does in Hegel's logic, it thereby loses all tests for the adequacy of its function and character as a notion.
In the development of the logical doctrines of Kant and Hegel by Lotze, Green, Sigwart, Bradley, Bosanquet, Royce, and others, there are indeed differences. But these differences only throw their common ground into bolder relief. This common ground is that, procedure by hypotheses, by induction, is, in the language of Professor Bosanquet, "a transient and external characteristic of inference."[16] And the ground of this verdict is essentially the same as Mill's, when he rejects hypotheses "made by the mind," namely, that such hypotheses are too subjective in their origin and nature to have objective validity. "Objective" idealism is trying, like Mill, to escape the subjectivism of the purely individual and "psychical" knower. But, being unable to reconstruct the finite knower, and being too sophisticated to make what it regards as Mill's naïve appeal to "hypotheses found in things," it transfers the real process of inference to the "objective universal," and the process of all thought, including inference, is now defined as "the reproduction, by a universal presented in a content, of contents distinguished from the presented content which also are differences of the same universal."[17]