Is this conclusion, that instinct precedes reflex in the developmental series, illogical? Not at all; for although the actual course of development is no more deductive than inductive, the logician tells us that these two types of inference are but the obverse and reverse of one and the same process. A general term is not conceivable except as embracing particulars, and particulars, in turn, require a generalized setting for their consideration. Creighton has described this process as follows: What we really obtain through an inductive inference is not only a general law, but also a perception of its concrete application to particular phenomena. This being so, it is clear that Induction and Deduction are not two different kinds of inference. Inference always implies an effort on the part of the mind to see how phenomena are necessarily connected according to some general principle; and, in carrying out this purpose, the mind must begin with the knowledge which it already possesses.
When the general law of connection is known, and the object is to discover the nature of some particular fact, the method of procedure is deductive. But, when the problem by which we are confronted is to read out of the facts of sense-perception the general law of their connection, the method of inference which must be employed is that of Induction.
But, from whatever point we set out, and whatever may be the immediate object of the inference, the result is always the same—an insight into the necessary connection of facts according to some general principle. It is not unusual to hear the remark made that modern science has been built up by the employment of the inductive method.
This must not, however, be interpreted to mean that deductive inferences are not also used in the discovery of scientific truth. Science (which is simply another name for systematic knowledge) is the product of thinking; and thought, as we have seen, is not limited to any one mode of procedure. Thought aims at extending knowledge, and so long as it can find any link of connection, or guiding thread, it is not limited to any one direction, or to any fixed mode of working. It is, of course, to be admitted— and this is true in the statement which we have quoted—that general laws cannot be discovered without an examination of particular facts, and that their validity must always be tested by comparison with the facts.
But as soon as a general law is discovered in any field, it is always used as a principle from which to deduce new results. When it is possible to employ mathematics in the calculation of these results, it is usually possible to extend our knowledge of the subject much more rapidly than before. Thus physics and astronomy owe their rapid development to the application of mathematics. It must be remembered, however, that this presupposes a certain stage of advancement—a certain inductive stage, as it were — on the part of the science. But even in this earlier stage we are constantly employing deduction, always reasoning out the results of certain guesses or suggestions to see if they hold true.
Both in ordinary life and in scientific procedure Induction and Deduction are constantly employed together as mutually supplementing each other in the work of organizing experience. The logic of instinct and reflex falls within this general provision that analysis and synthesis, deduction and induction, go hand in hand. Not only is our derivation of reflex from instinct logically sound as an inference, but the very processes of integration and individuation referred to as being parallel in the conclusions reached by Herrick and Coghill are a biological counterpart of the higher processes of reasoning and inference.
But the logic of instinct can be carried a step farther, and at the same time in a manner which we shall have occasion to elaborate upon in Chapter IV. The logician speaks of two kinds of definition: (1) the twofold division by contradictories, and (2) the multiple division by limits or contraries. The first of these establishes the laws of identity, excluded middle, and contradiction, all three of which are derived from the proposition that a thing is either A or not-A. In other words, the particularity of anything is such that it can always be placed either within or without a certain class.
The adequacy of this classification is determined by an inherent quality of the particular, and not by any prearranged scheme. In other words, a natural dichotomy permits of no choice. This is the principle of dichotomy, and it is applicable to all primitive modes of behavior. Concretely, an act of behavior stands off as a pattern, or figure, upon an undifferentiated ground. In this way it becomes a particular act. However vague and lacking in precision, so much of whatever it might be as emerges to become what it is stands out against a less differentiated and less articulate ground.
What it is which thus emerges in the first instinctive response of suckling may be crude and ill-defined; yet such definition as the act possesses is not comparable to anything else present at the time. Instead, an original act is in dichotomous opposition to its surroundings—that is, to the inarticulateness of any other effects produced by This emergence of a dominant tendency of behavior, held together not by a linkage of parts but by an articulation of the whole into one pattern, constitutes the most primitive “all-or-none” type of behavior.
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