substances? Consciousness may differ widely from matter and still require no one simple substance for its existence and activity.
The only solid argument that remains for the soul hypothesis is that of mental synthesis. The very consideration, however, on which the spiritualist lays so much stress serves as his best refutation. That phenomena of consciousness differ radically from material ones is a fundamental proposition with the psychologist in general, and with the spiritualist in particular, but this is far from supporting spiritualism. On the contrary, it overthrows his last stronghold. For if mental facts differ in kind from physical material facts, it is poor reasoning to raise difficulties pertaining to one religion, and carry them over into a totally different one. It would be senseless to raise aesthetic difficulties in chemistry or mechanics, but it is no better to reason that because a medium is required for physical objects, movements, forces to combine their effects in one resultant, therefore, a medium, a substance, a soul, is also required for a synthesis of a totally different order of phenomena, those of consciousness. The two orders differ in kind, and what is found necessary in one, is not for that reason also proven to be indispensable to the other. It must first be proven that the conditions of unification are the same in both before the argument from mental synthesis may be accepted as valid. States of consciousness may become synthesized without any medium, without any tertium quid, without any soul.
The spiritualist by his "soul" hypothesis really undermines his own position. For if it be granted that the conditions of unification are the same in mental as in physical activity; that a medium is required in both in order to get a unity, a resultant, then the whole "soul" structure tumbles to the ground. Material and mental phenomena cannot possibly belong to two radically different substances, if the conditions of their activity are exactly of the same nature. It would have been perfectly logical had the difference between consciousness and the physical world been asserted and emphasized, and had the medium, the soul, been totally left out.
The greatest difficulty, however, which the spiritualist encounters is the interaction of the two substances. If matter and soul are different in nature how can they interact, how can they come into any relation? Hours in so far as they are different from pounds, or miles, have nothing in common, and as such do not interact; an hour cannot modify a pound, nor can pounds change hours, and if this holds true of phenomena of the external world where the difference after all is not so very great, it must with special force recoil on the spiritualist where the soul and body are so totally different in all respects. The only way out of the difficulty, if one is consistent and is not afraid to take the consequences, is to introduce the miraculous and say that the interaction is due to the intervention of the deity. This view was in fact taken by the followers of Descartes. The spiritualist, however, with a philosophical and scientific training will rather be inconsistent and support his view by all kinds of props than to accept such a conclusion, because he knows that it practically means defeat, it means that the hypothesis is not working, and that the soul must take shelter under the wing of the deity, the refuge of ignorance. From a purely scientific standpoint we must reject this soul-hypothesis. The first requirement of a scientific hypothesis is that its hypothetical cause should be of such a nature as to be verifiable by experiment and observation. Now in the case of the soul, this condition is not fulfilled. The soul is something that lies outside the range of experience, and could never be brought within the limits of empiricism, the basis of science. The spiritualist, in fact, has not even a positive notion of his "soul," he either frames it in wholly negative terms, that it is not changeable, that it is not material; or, if pressed hard, he falls back on the phenomena of consciousness, the very phenomena the soul is called for to explain.
Furthermore, a scientific hypothesis is justified and found useful, if shown that it makes the facts more easily understood. This cannot be shown in the case of the soul. As a hypothesis the soul is useless and scientifically unjustifiable. The acceptance of the "spirit," of the soul, does not make it a bit easier for us to comprehend the modus operandi of the states of consciousness The soul is an immutable, indefinite, indescribable, incomprehensible being, and the insuperable difficulty of how it gives rise to conscious activity requires another hypothesis. If mental phenomena present difficulties, spiritualism doubles them. The soul in fact, is the "double," the ghost of consciousness. The soul is an unverifiable superfluous entity, it is not a vera causa in nature; it explains nothing, and without removing difficulties is only introduced as an additional burden.
Before we dismiss the soul hypothesis, we may point out that it must be rejected on quite different grounds, it is at bottom unscientific, it is metaphysical, it goes into the ultimate nature of things, an investigation that does not fall within the province of science. The soul-hypothesis assumes the existence of an abiding unchangeable entity behind the veil of mental phenomena, an entity which in the flow and change the phenomena remains the same and is the really real, the ultimate nature of the facts of consciousness. This belongs to the ontological part of metaphysics, but should not be introduced into science. The reader will realize now, why the whole complicated "soul discussion" is taken up here. It is to emphasize the fact that psychology has nothing to do with substances, noumena, entities, and quiddities, that psychology has nothing to do with the "inner nature" of consciousness. Psychology, like all other sciences, describes, classifies, and investigates by means of observation and experimentation facts of consciousness and their relations, and endeavors to express these relations in general formulae or laws; all attempts to make of psychology more than this can only result in bad metaphysics.
The materialistic hypothesis is even worse metaphysics than is the spiritualistic one. It is a hypothesis which in spite of its evident absurdity is none the less in favor with some representatives of the medical profession. Matter and force, as Buchner puts it, give rise to, or produce consciousness, or as Cabanis and Moleschott express it "the brain produces thought as the liver secretes bile." This hypothesis is unscientific and metaphysical, because it attempts to penetrate into the inner nature of consciousness, and claims to have it resolved into "matter." It is bad metaphysics, because it takes its "matter" on trust, without any critical reflection. Moreover it is more crude and worse metaphysics than is the soul hypothesis, because it lacks even the recognition of the most elementary, psychological proposition, namely, the knowledge of fundamental difference between mental and material phenomena.
Turning now to the faculty-hypothesis, we find that it is nothing else than spiritualism under a somewhat different form. The faculty-hypothesis chops the mind into many different parts, termed faculties, one is for reading, another for speaking, another for remembering, another still for willing, and so on. Sometimes they are limited to a few, and sometimes they are multiplied to infinity. The faculty-hypothesis is a cheap edition of spiritualism, it is spiritualism many times over. Instead of one soul it has many of them. Spiritualism has but one difficulty and that is the soul which, like an omnipotent deity, presides in some mysterious way over mental and organic activities. The faculty-hypothesis has an infinite number of them, inasmuch as it multiplies the deity into an endless number of gods and spirits that take charge of different psychic and psychomotor departments.
One can see the reason of the faculty hypothesis. It originated with people who as a rule are inclined to accept uncritically words for realities. Thus, will, memory, words that are only collective terms for many different states of mind, names furnished by the language of unreflective common sense, are naively taken as indicating some substantial entities, or little spirits existing somewhere in the brain.
IX The Transmission Hypothesis
The transmission hypothesis advanced by James is a modification of the soul hypothesis. The transmission hypothesis postulates the existence of a physical world and of an independent universe of consciousness. Consciousness, however, cannot manifest itself in this sublunar world without the occurrence of definite physical changes. That level of physical changes which makes the manifestations of consciousness possible is termed
