Anyhow (sticking to the naïve standpoint), it is true that the stimulus to that particular form of reflective thinking termed logical theory is found when circumstances require the act of thinking and nevertheless impede clear and coherent thinking in detail; or when they occasion thought and then prevent the results of thinking from exercising directive influence upon the immediate concerns of life. Under these conditions we get such questions as the following: What is the relation of rational thought to crude or unreflective experience? What is the relation of thought to reality? What is the barrier which prevents reason from complete penetration into the world of truth? What is it that makes us live alternately in a concrete world of experience in which thought as such finds not satisfaction, and in a world of ordered thought which is yet only abstract and ideal?
It is not my intention here to pursue the line of historical inquiry thus suggested. Indeed, the point would not be mentioned did it not serve to fix attention upon the nature of the logical problem.
It is in dealing with this latter type of question that logical theory has taken a turn which separates it widely from the theoretical implications of practical deliberation and of scientific research. The two latter, however much they differ from each other in detail, agree in a fundamental principle. They both assume that every reflective problem and operation arises with reference to some specific situation, and has to subserve a specific purpose dependent upon its own occasion. They assume and observe distinct limits—limits from which and to which. There is the limit of origin in the needs of the particular situation which evokes reflection. There is the limit of terminus in successful dealing with the particular problem presented—or in retiring, baffled, to take up some other question. The query that at once faces us regarding the nature of logical theory is whether reflection upon reflection shall recognize these limits, endeavoring to formulate them more exactly and to define their relationships to each other more adequately; or shall it abolish limits, do away with the matter of specific conditions and specific aims of thought, and discuss thought and its relation to empirical antecedents and rational consequents (truth) at large?
At first blush, it might seem as if the very nature of logical theory as generalization of the reflective process must of necessity disregard the matter of particular conditions and particular results as irrelevant. How, the implication runs, could reflection become generalized save by elimination of details as irrelevant? Such a conception in fixing the central problem of logic fixes once for all its future career and material. The essential business of logic is henceforth to discuss the relation of thought as such to reality as such. It may, indeed, involve much psychological material, particularly in the discussion of the processes which antecede thinking and which call it out. It may involve much discussion of the concrete methods of investigation and verification employed in the various sciences. It may busily concern itself with the differentiation of various types and forms of thought—different modes of conceiving, various conformations of judgment, various types of inferential reasoning. But it concerns itself with any and all of these three fields, not on their own account or as ultimate, but as subsidiary to the main problem: the relation of thought as such, or at large, to reality as such, or at large. Some of the detailed considerations referred to may throw light upon the terms under which thought transacts its business with reality; upon, say, certain peculiar limitations it has to submit to as best it may. Other considerations throw light upon the ways in which thought gets at reality. Still other considerations throw light upon the forms which thought assumes in attacking and apprehending reality. But in the end all this is incidental. In the end the one problem holds: How do the specifications of thought as such hold good of reality as such? In fine, logic is supposed to grow out of the epistemological inquiry and to lead up to its solution.
From this point of view various aspects of logical theory are well stated by an author whom later on we shall consider in some detail. Lotze[11] refers to "universal forms and principles of thought which hold good everywhere both in judging of reality and in weighing possibility, irrespective of any difference in the objects." This defines the business of pure logic. This is clearly the question of thought as such—of thought at large or in general. Then we have the question "of how far the most complete structure of thought ... can claim to be an adequate account of that which we seem compelled to assume as the object and occasion of our ideas." This is clearly the question of the relation of thought at large to reality at large. It is epistemology. Then comes "applied logic," having to do with the actual employment of concrete forms of thought with reference to investigation of specific topics and subjects. This "applied" logic would, if the standpoint of practical deliberation and of scientific research were adopted, be the sole genuine logic. But the existence of thought in itself having been agreed upon, we have in this "applied" logic only an incidental inquiry of how the particular resistances and oppositions which "pure" thought meets from particular matters may best be discounted. It is concerned with methods of investigation which obviate defects in the relationship of thought at large to reality at large, as these present themselves under the limitations of human experience. It deals merely with hindrances, and with devices for overcoming them; it is directed by considerations of utility. When we reflect that this field includes the entire procedure of practical deliberation and of concrete scientific research, we begin to realize something of the significance of the theory of logic which regards the limitations of specific origination and specific outcome as irrelevant to its main problem, which assumes an activity of thought "pure" or "in itself," that is, "irrespective of any difference in its objects."
This suggests, by contrast, the opposite mode of stating the problem of logical theory. Generalization of the nature of the reflective process certainly involves elimination of much of the specific material and contents of the thought-situations of daily life and of critical science. Quite compatible with this, however, is the notion that it seizes upon certain specific conditions and factors, and aims to bring them to clear consciousness—not to abolish them. While eliminating the particular material of particular practical and scientific pursuits, (1) it may strive to hit upon the common denominator in the various situations which are antecedent or primary to thought and which evoke it; (2) it may attempt to show how typical features in the specific antecedents of thought call out diverse typical modes of thought-reaction; (3) it may attempt to state the nature of the specific consequences in which thought fulfils its career.
(1) It does not eliminate dependence upon specific occasions as provocative of thought, but endeavors to define what in the various occasions renders them thought-provoking. The specific occasion is not eliminated, but insisted upon and brought into the foreground. Consequently, empirical considerations are not subsidiary incidents, but are of essential importance so far as they enable us to trace the generation of the thought-situation. (2) From this point of view the various types and modes of conceiving, judging, and inference are treated, not as qualifications of thought per se or at large, but of reflection engaged in its specific, most economic, effective response to its own particular occasion; they are adaptations for control of stimuli. The distinctions and classifications that have been accumulated in "formal" logic are relevant data; but they demand interpretation from the standpoint of use as organs of adjustment to material antecedents and stimuli. (3) Finally the question of validity, or ultimate objective of thought, is relevant; but relevant as a matter of the specific issue of the specific career of a thought-function. All the typical investigatory and verificatory procedures of the various sciences indicate the ways in which thought actually brings to successful fulfilment its dealing with various types of problems.
While the epistemological type of logic may, as we have seen, leave (under the name of applied logic) a subsidiary place open for the instrumental type, the type which deals with thinking as a specific procedure relative to a specific antecedent occasion and to a subsequent specific fulfilment is not able to reciprocate the favor.