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 the physiological nervous processes, at the same time have their action manifested by a parallel modification of psychic processes. Illusions, hallucinations, and delusions, changes in reasoning and willing, changes in memory, amnesia and paramnesia, all these can be induced by the influence of poisons. Thus we find that the two series of phenomena, the psychic and the physiological or physical are intimately related.
Pathology and psychiatry with their vast stores of facts go to confirm the psycho-physiological hypothesis. In general paralysis, for instance, we meet conditions somewhat similar to those of alcoholic intoxication. At first inhibitions are removed, the psychomotor processes become deranged and slightly stimulated, sooner or later to be followed by gradual paralysis. The process of dissolution progresses from the highest most complex, least stable functions, memory, intelligence, will and so on, to the lower, less complex and more stable functions, reading, writing, playing, etc., finally reaching to the very lowest, to the simplest co-ordination of movements, mastication, swallowing, etc. A post-mortem examination of the brain uniformly reveals a profound degeneration of the brain cells. In the various forms of epilepsy and in most cases of chronic insanity, ending in dementia, we find on examination as a rule, some degeneration of the brain cells.
In cases of the many forms of aphasia, science triumphed in discovering the brain lesion. In motor aphasia the third frontal convolution, or that of Broca is found to be degenerated, in sensory aphasia the degeneration is in the first temporo-sphenoidal convolution, or that of Wernicke. In many other nervous diseases where there is a profound change in the sensori-motor functions, such as posterior spinal sclerosis or locomotor ataxia, acute ascending paralysis, acute poleomyelitis anterior, syringomyelia, etc., we also find degeneration in some one part of the cerebro-spinal nervous system. Thus in tabes we find a degeneration of the posterior root zones often associated with similar lesions in the intramedullory continuation of the several cranial nerves. In poliomyelitis anterior we find an inflammation of the anterior cornua (sometimes extending in the antero-lateral columns); the multipolar cells with their dendrons and neuraxons are destroyed. In syringo-myelia we find the formation of one or more cavities within the substance of the spinal cord, usually within the horns of the gray matter the cavities being filled with a fluid which is either liquid or gelatinous. We find in these diseases definite organic changes concomitant with definite sensori-motor modifications.
In the functional diseases belonging to the province of psycho-pathology, diseases such as are known under the vague term of hysteria in all its protean manifestations, the different forms of anaesthesia and amnesia, abulia, psychopathic chorea, astasia-abasia and numerous others, where no organic lesion in the cerebro-spinal nervous system can possibly be discovered, we have good reasons for suspecting some functional derangement into the psysiological processes of the nervous system. My own psycho physiological investigations in this line tend strongly to confirm the theory that all functional diseases are disassociations of functioning brain cell-systems, and that the gravity of the disease depends on the extension of such functional dissociations. Thus we find that neuro-pathology and the recent science of psycho-pathology with all the wealth of facts and discoveries at their disposal give evidence of the truth of the psycho-physiological hypothesis; in fact, this is their only working hypothesis sine qua non the very existence of these sciences.
The psycho-physiological hypothesis finds special support in the brilliant investigations of experimental physiology. The experiments of Munk, Ferrier, Hitzig, Brown-Sequard, Goltz, Schiff, and others clearly show the correlation of brain functions with psychic activity. They show, for instance, in animals that the physiological processes in the occipital lobes are correlated with vision, that those of the temporal lobe, especially of the superior temporo-sphenoidal convolution are correlated with hearing, that sensations of smell are concomitant with
