CHAPTER IV FUNCTIONAL PSYCHOLOGY
It now becomes necessary to review that period of Dewey's philosophical career which is marked by the definite abandonment of the idealistic standpoint, and the adoption of the method of instrumental pragmatism. It has already been seen that there is a close connection between the "functionalism" which now begins to appear, and the "Psychological Standpoint" set forth in the preceding pages of this review. It is not possible, however, to account for all the elements which contribute to this development. Dewey was active in many fields and received suggestions from many sources. It seems best, in dealing with this period, to "follow the lead of the subject-matter" and avoid a priori speculation on the factors which determined the precise form of Dewey's mature standpoint in philosophy.
Dewey had always kept in mind the idea that the synthetic activity whereby self-consciousness evolves the ideality of the world must operate through the human organism. He had frequently referred to Green's saying that the Eternal Self-Consciousness reproduces itself in man, and to similar notions in Caird and Kant; but he had never considered, in a detailed way, how the organism might serve as the vehicle for such a process. His ethical theory, with its analysis of individuality into capacity and environment, tended to bring the body-world relationship into the foreground, and the idea that theory is relative to action tended to emphasize still more the relation of thought to the bodily processes. Dewey finally discovers the basis upon which the synthetic activity of the self, the thought process, may be described empirically and concretely. Organism-in-relation-to-environment becomes the key-stone of his theory of knowledge. Thought is interpreted as a function of the organism, biologically considered, and the biological psychology which results from this mode of interpretation is commonly known as 'functional psychology.'
The functional psychology is presented in a series of articles in the Philosophical Review and the Psychological Review, published between 1894 and 1898. The most important of these is "The Reflex Arc Concept in Psychology," published in the Psychological Review in 1896.[116] Since it is the only article in the series which gives a complete view of the theory, it will be made the basis for the discussion of the functional theory of psychology.
The reflex arc concept in psychology, Dewey says, recognizes that the sensory-motor arc is to be taken as the unit of nerve structure, and the type of nerve function. But psychologists do not avail themselves of the full value of this conception, because they still retain in connection with it certain distinctions which were used in the older psychology. "The older dualism between sensation and idea is repeated in the current dualism of peripheral and central structures and functions; the older dualism of body and soul finds a distinct echo in the current dualism of stimulus and response."[117] These rigid distinctions must be set aside, and the separated elements must be viewed as elements in one sensory-motor coördination. Each is to be defined, not as something existing by itself, but as an element functioning in a concrete whole of activity. Thus, if we are to study vision, we must first take vision as a sensory-motor coördination, the act of seeing, and within the whole we may then be able to distinguish certain elements, sensations, or movements, and define them according to their function in the total act of seeing. The reflex arc idea, as commonly employed, takes sensation as stimulus, and movement as response, as if they were actually separate existences, apart from a coördination. Response is said to follow sensation, but it is forgotten that the sensation which preceded was correlated with a response, and that the response which follows is also correlated with sensation. Sound, for instance, is not a mere sensation in itself, apart from sensory-motor coördination. Hearing is an act, and while sound may, for purposes of study, be abstracted from the total, it is not, in itself, independent of the total act of hearing.
"But, in spite of all this, it will be urged, there is a distinction between stimulus and response, between sensation and motion. Precisely; but we ought now to be in a condition to ask of what nature is the distinction, instead of taking it for granted as a distinction somehow lying in the existence of the facts themselves."[118] The distinction which is to be made between them must be made on a teleological basis. "The fact is that stimulus and response are not distinctions of existence, but teleological distinctions, that is, distinctions of function, or part played, with reference to reaching or maintaining an end."[119] There are two kinds of teleological distinction that can be made between stimulus and response, or rather, the teleological interpretation has two phases.