This has been one of the classical objections to the doctrine of inter-actionism; and it must not be thought that I have failed to take into account this alternate theory. But opposed to this view of the case we have the facts—(1) that the state of consciousness, and not the brain-state, is surely here the important factor; and (2) that, even were the supposition true, this nervous action or influence must cease at the periphery of the body; for, were this not the case, we should already have exceeded the limits of the orthodox physiological theory, which contends that one portion of the body affects another portion (only), and does not contend or pretend that this action may extend beyond the surface of the body; for, if it did so extend, we should have a nervous current without nerves—an appalling fact, and one totally opposed to accepted physiological teaching!
In order for nervous energy or life force to exist independent of the body (upon the functionings of which it supposedly depends), it would be necessary for us to reconstruct the mechanistic interpretation of life, since it would show that life is not dependent upon the body for its existence, but might exist independently of it, which is the very point in dispute. It cannot logically be contended, therefore, that the energy which we here see in operation lies in the nerves or in the brain-centres, but rather that it is a separate force, which physiology, as taught today, cannot account for. Introspection and experiment seem to unite in telling us that this energy is none other than the human Will.
But if it be granted, on the other hand, that the will is a physical energy, we immediately encounter certain difficulties which must not be ignored. In the first place, if the will be a physical energy, it is subject to the law of Conservation, and, consequently, must be included within the cycle of forces which that law encompasses. Light, heat, chemical affinity, etc., are supposed to be mutually convertible and transmutable; and, according to the present hypothesis, Will must also be included in this series! But every energy we know in the physical universe is a non-intelligent energy, and, as I have pointed out elsewhere, if we make the human will thus subject to the law of Conservation, it seems to form a unique exception to the law. For we know (if our consciousness tells us anything) that willing is an intelligent act, and we should consequently have this conscious act or intent left over in the equation. For we have, in all other cases, purely physical energy, and in this case physical energy plus something (conscious intent). The law of Conservation tells us that one energy is derived from another, and is converted again into another form of physical energy, when it is expended. But if will, ex hypothesi a physical energy, is derived from another physical energy (by a process of combustion, or what you will), we have here a case of the lesser including the greater—of a thing giving rise to something greater and more inclusive than itself—which is contrary to all accepted thinking. The will, therefore, cannot be entirely subject to the law of Conservation, but appears to draw upon an additional fund or source of energy, which is infused into it, as it were, from without. This "thing" which is infused or super-added, this "something" which is the "plus" in our equation, appears to be the directive element, the life element, the sentient element—which is thus shown to lie outside the law of Conservation, as many physicists and philosophers (Lodge, Crookes, Bergson, etc.) have for some time past contended it must or might lie.
One significant fact, in this connection, is that while the law of Conservation is doubtless true, so far as it goes, there is also in operation another law, well known to physicists, called the law of the Degradation of Energy, which asserts that energies of a higher order are constantly being converted into energies of a lower order. This law maintains that energies of a lower order cannot be reconverted into energies of a higher order. All other energies are being slowly but surely converted into heat—the lowest of all forms of energy. And this heat is gradually being dissipated, or radiated away, into space, so that, at some distant day, our universe will be cold and lifeless, like the moon.
Now it is a significant fact that the single exception to this rule consists in, and is constituted by, life, or vital energy, which is constantly building lower forms of energy into higher forms. Life is certainly the highest form of energy which we know in this world, and all energies are below this in rank—as may readily be proved by an appeal to the facts of nutrition and metabolism. And, as life is constantly being added to or infused into the world (as the population increases), it is certainly true that there is here a definite increase of the sum-total of the highest form of energy of which we have any knowledge. Life thus occupies not only an important but a unique position—in that it is constructive instead of destructive; and this fact alone should give us pause, and make us ask whether life is, in its totality, subject to and included within the law of Conservation of Energy.
The establishment of the fact that the human will is a definite physical energy is of importance also, because of its bearing upon the problem of the connection or inter-relation of mind and matter. Theories as to this bond or connection have been propounded since the dawn of philosophy. Aristotle and others wrote and thought deeply upon this subject. As is well known, this question formed one of the central points of debate in the works of Hobbes, Berkeley, Hume, Descartes, Leibnitz, Spinoza, Kant, Hegel, Lotze, and many other philosophical writers—all of whom wrote and speculated at length upon this subject. The theories which have been advanced in the past are briefly as follows:[19]
1st. Crude Materialism.—This doctrine contends that consciousness is merely matter, or energy, or matter in motion. It is not necessary to discuss this theory here, as it is not held today by any scientist of the first rank.
2nd. Epiphenomenalism.—This doctrine found its foremost champion in Huxley. It contends that the important happenings are the brain-changes—which are causally connected—and that our thoughts, or corresponding states of consciousness, merely accompany the brain-changes, just as the shadow of a horse may be said to accompany the horse.
The objections of this doctrine are:—
(a) That it is just as inconceivable to believe or imagine that brain-changes generate consciousness as it is to imagine that consciousness generates brain-changes.