While emphasizing the continuity between non-logical and logical operations, we must keep in mind that their distinction is of equal importance. Confusion at this point is fatal. A case in point is the confusion between non-logical and logical observation. The results of non-logical observation, e.g., looking and listening, are direct stimuli to further conduct. But the purpose and result of logical observation are to secure data, not as direct stimuli to immediate conduct but as stimuli to the construction or verification of hypotheses which are the responses of the logical operation of imagination to the data. Hypotheses are anticipatory. But they differ from non-logical anticipation in that they are tentatively, experimentally, i.e., logically anticipatory. The non-logical operations of memory and anticipation lack just this tentative, experimental character. When we confuse the logical and non-logical operations of these processes the result is either that logical processes will merely repeat non-logical operations in which case we have inference that is tautologous and trifling; or the non-logical will attempt to perform logical operations, and our inference is miraculous. If we seek to escape by an appeal to habit, as in empiricism, or to an objective universal, as in idealism and neo-realism, we are merely disguising, not removing the miracle.
It may be thought that this confusion would be most likely to occur in a theory which teaches that non-logical processes are carried over into logical operations. But this overlooks the fact that the theory recognizes at the same time that these non-logical operations undergo modification and adaptation to the demands of the logical enterprise. On the other hand, those who make all perceptions, memory, and anticipation, not to speak of habit and instinct, logical, have no basis for the distinction between logical and non-logical results; while those who refuse to give the operations of perception, memory, etc., any place in logic can make no connections between logical and non-logical conduct. Nor are they able to distinguish in a specific case truth from error.
In all logics that fail to make this connection and distinction between logical and non-logical operations there is no criterion for data. If ultimate simplicity is demanded of the data, there is no standard for simplicity except the minimum sensibile or the minimum intelligibile which have recently been resurrected. On the other hand, where simplicity is waived, as in the logic of objective idealism, there is still no criterion of logical adequacy. But if we understand by logical data not anything that happens to be given, but something sought as material for an hypothesis, i.e., a proposed solution (proposition) of an ambiguous object of conduct and affection, then whatever results of observation meet this requirement are logical data. And whenever data are found from which an hypothesis is constructed that succeeds in abolishing the ambiguity, they are simple, adequate, and true data.
No scientist, not even the mathematician, in the specific investigations of his field, seeks for ultimate and irreducible data at large. And if he found them he could not use them. It is only in his metaphysical personality that he longs for such data. The data which the scientist in any specific inquiry seeks are the data which suggest a solution of the question in which the investigation starts. When these data are found they are the "irreducibles" of that problem. But they are relative to the question and answer of the investigation. Their simplicity consists in the fact that they are the data from which a conclusion can be made. The term "simple data" is tautologous. That one is in need of data more "simple" means that one is in need of new data from which an hypothesis can be formed.
It is true that the actual working elements with which the scientist operates are always complex in the sense that they are always something more than elements in any specific investigation. They have other connections and alliances. And this complexity is at once the despair and the hope of the scientist; his despair, because he cannot be sure when these other connections will interfere with the allegiance of his elements to his particular undertaking; his hope, because when these alliances are revealed they often make the elements more efficient or exhibit capacities which will make them elements in some other undertaking for which elements have not been found. A general resolves his army into so many marching, eating, shooting units; but these elements are something more than marching, shooting units. They are husbands and fathers, brothers and lovers, protestants and catholics, artists and artisans, etc. And the militarist can never be sure at what point these other activities—I do not say merely external relationships—may upset his calculations. If he could find units whose whole and sole nature is to march and shoot, his problem would be, in some respects, simpler, though in others more complex. As it is, he is constantly required to ask how far these other functions will support and at what point they will rebel at the marching and shooting.
Such, in principle, is the situation in every scientific inquiry. When the failure of the old elements occurs it is common to say that "simpler" elements are needed. And doubtless in his perplexity the scientist may long for elements which have no entangling alliances, whose sole nature and character is to be elements. But what in fact he actually seeks in every specific investigation are elements whose nature and functions will not interfere with their serving as units in the enterprise in hand. But from some other standpoint these new elements may be vastly more complex than the old, as is the case with the modern as compared with the ancient atom. When the elements are secured which operate successfully, the non-interfering connections can be ignored and the elements can be treated as if they did not have them—as if they were metaphysically simple. But there is no criterion for metaphysical simplicity except operative simplicity. To be simple is to serve as an element, and to serve as an element is to be simple.
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