It is true that the so-called "Voluntaristic school" claims that psychology is the only science that has no assumption at its basis. The representative of that school claims that there is but one "unitary experience." From this "unitary experience natural science abstracts the knowing subject and as such deals with abstract mediate experiences requiring auxiliary assumptions, not so is psychology which deals with experience as it is immediately presented to the experiencing subject." According to the voluntarist natural science deals with mediate experience, while psychology deals with immediate experience requiring no assumptions.
This argument is questionable on the very face of it. For the existence of that "unitary experience" is itself an assumption; implies that the experience and the object given by the experience are one. Such a unification of experience and external object implied in "unitary experience" is a metaphysical assumption which idealistic philosophy may prove as being true, but which the psychologist can not possibly accept as given directly by experience itself. Furthermore, the concept "experience" cannot stand by itself, it implies assumptions; an experience must be of something that lies outside that experience. I have an experience of a house yonder, but the house yonder is not an experience unless regarded from a metaphysical or epistemological standpoint, but then we overstep the boundaries of psychology which deals with experiences of individual organisms and enter the field of philosophy that deals with experience in general.
In taking the most simple psychological element, namely sensation, we have its correlative in the external stimulus; there can be no sensations without a stimulus, but that stimulus is no longer a sensation nor is it any other psychic process, such for instance as an idea. Psychologically considered the identification of the stimulus with psychic state or process is incorrect, because it would mean that all sensory processes are initiated only by sensations or ideas.
Again, if we come to ask in what sense we understand the concept "immediate experience," we find further difficulties. For if the consciousness be of the anoetic type, to borrow the term from Stout, there is neither mediate, nor immediate experience; if the consciousness is of the noetic type it is questionable as to what we mean by "immediate." For it may be contended with the modern realist that the knowledge of the object as given in sensation is immediate, while the knowledge of sensation itself with which psychology deals is not immediately given; it requires a long training before this is separated and sifted from experience; the psychological aspect of experience is really secondary, and as such mediate.
If by "immediate" we mean to indicate the fact that the psychic process must antedate the knowledge of the external objective world, the proposition can be contested once more; for along with the psychic process the object also is given; especially is this true of the idealistic metaphysical presupposition of the voluntaristic school that identifies the objective world with the given primary experience. The objective and subjective aspects of the "unitary experience" are both supposed to be given together and, as such, are both immediate. Natural science abstracts the subjective aspect and psychology abstracts the objective aspect the "mediate experience." We should, however, question the term "mediate experience." What may "mediate experience" mean? If experience has any meaning, it means something gone or lived through directly, immediately; but then all experience is immediate, otherwise it cannot be experience. A mediate experience as contrasted with immediate experience can only mean experience inferred, experience not experienced, a concept contradictory in its very nature and definition, and must be therefore rejected as a meaningless term. The fact is, that "mediate experience" is an inappropriate and misleading term for physical processes which as such are neither experience nor mediate.
The very statement of the voluntaristic psychologist discloses the hidden assumption. There is a unitary experience which falls asunder into mediate experience of natural science and immediate experience, the subject matter of the psychologist. If this be so, then the psychologist does not deal with the totality of experience. Since the mediate experience―part of the "unitary experience" falls outside its domain, it deals only with experience in so far as it is regarded as immediate. Evidently psychology requires presuppositions to supplement the abstracted mediate aspect of the unitary experience. For the voluntaristic school will surely admit that unitary experience is given neither in the mediate aspect nor in the immediate aspect alone, and as science deals either with the one, or with the other, presuppositions are ipso facto also indispensable in psychology.
Moreover, psychology even from the standpoint of the voluntaristic school requires more presuppositions than the natural sciences. For experience, even if it be immediate, must still be of something other than itself. The sensation white is of something white, the touch sensation hard is of something hard, the pain sensation prick is of something sharp, and so on. Now if this something, if that other of which there is immediate experience be the so-called "mediate experience" as this is the supplementary part of the unitary experience, of the total reality, then "immediate experience" is experience of "mediate experience." The science then that deals with immediate experience must postulate mediate experience as one of its fundamental presuppositions. Thus we come once more to the conclusion, and this time from quite a different standpoint, that psychology as science in general has its presuppositions, and that it furthermore presupposes all the presuppositions of the natural sciences.
Psychology explains the subject and object in consciousness, and that only in relation to the question of "how,"―how we come to know this or that object, but whether there is an object or subject independent of the experiencing thought what the nature of that object or subject is, whether of mental experience stuff or of some extra-mental material, is a question that does not belong to the domain of psychology. The answer is differently given by the idealist, materialist, realist, monist. In short, the problem of "what" belongs not to psychology, but to the province of metaphysics. The Voluntaristic school in denying all presuppositions in psychology starts with a purely metaphysical speculation of the idealistic stamp, namely, in postulating that the external object of psychic experience is identical with that same experience. Psychology or any other science must reject unhesitatingly such metaphysical speculations.
XII The Inductive Basis of the Positive Psychological Hypothesis
It now remains for us to examine the psycho-physiological hypothesis. This last hypothesis fully accepts the difference between the two series of facts, the material and the mental, but instead of going to look for "the other side," instead of going into metaphysics, it takes the two different series as its data, and considers them as co-ordinate. It does not trouble itself as to whether there is a soul behind the scenes, all it has to consider is facts, phenomena that can be observed and experimented upon. The co-ordination it assumes is not an assumption based on abstract philosophical speculations, on subtle hair-splitting, but is based on experience.
Numerous facts from pathology and experimental physiology go to prove that mental states have their physiological correlatives. It is enough to mention the fact of the influence of toxic matters on the brain and the effected mental disturbances. In alcoholic intoxication, for instance, we first meet with an unloosening of higher psychic inhibitions; in the initial stage of intoxication there is an apparent heightening of mental and motor activity, and then as the quantity of the poison absorbed by the blood and conveyed to the cerebro-spinal nervous system is increased, a progressive paralysis of psychomotor life sets in. At first the highest psychic functions, the moral and intellectual processes are disturbed and finally paralyzed; and this paralysis slowly descends to the lower and more stable functions, such as speech and writing, then affecting the coordination of grosser movements, such as running, walking, standing, sitting; and as the action of the poison increases, the organic, respiratory functions become affected, finally ending in death. Different drugs and poisons that act on the cerebro-spinal nervous system produce different symptoms, but all of them, while influencing