In considering the first hypothesis, (namely, that mind and body act on one another as two things,) Professor Höffding shows that it is inconsistent with the law of the conservation of energy. For, at the point where the nervous process is converted into mental activity, one sum of physical energy would disappear without being replaced by another sum of the same kind. As matter of fact no disappearance of energy takes place on account of the arising of a conscious state. The chain of psychical causation is not broken; its completeness no more suffers than if states of consciousness did not arise at all. Nor on the other hand does consciousness affect the sum of physical energy; it is hardly conceivable that it should even change the direction of such energy (the sum supposably remaining constant, as is sometimes held), since to do this it must itself become a physical force. Moreover, if there is a relation of cause and effect between the brain and consciousness it would seem as if an interval of time must elapse between the process in the brain and the rising of the conscious state, a view to which the teachings of physiology lend no likelihood.
The second hypothesis regards matter as the real or actual thing and mind as an effect or form of it. Such materialism is certainly older than the now prevalent doctrine of the interaction of two distinct things. Homer and the earliest Greek philosophers held to it. Similar views prevailed among the early Christian fathers before Augustine. Modern materialists, however, regard the mind, not in the earlier fashion as semi-corporeal, but as a function or form of the corporeal. Yet when we closely consider the matter, we find that to conceive of the function of a bodily organ is simply to conceive of that organ as in activity. As Goethe said, "Function is das Dasein in Thätigkeit gedacht." But a bodily organ in activity is just as much corporeal as one at rest, and anything without corporeal attributes can no more be the function of such an organ than it can be the organ itself. The conception of function (in the physiological sense) as truly as that of matter implies something that exists in spacial form; while thoughts and feelings are without spacial form.
In dealing with the third hypothesis, (namely, that body is a form or product of mind,) Professor Höffding does not so much criticise it as explain a modified and interesting form in which Lotze held it. It is not, however, the view which he adopts.
To the fourth hypothesis he gives his adhesion. The parallel and proportional relations between consciousness and brain-activity point, according to him, to an underlying identity between the two. One and the same principle, he says, has found its expression in a two-fold form. The physical interaction between the elements of which the nervous system is composed, is an outward form of the inner ideal unity of consciousness. What we immediately experience as thoughts, feelings, volitions, has its physical representation in certain brain-processes, which as such are under the law of the conservation of energy, though this law has no application to the relation between brain-processes and consciousness. It is as if one and the same content were expressed in two languages.
This conclusion, however, he repeats, is but an empirical formula and has provisional value only. One substance, he says, acts in both consciousness and the bodily organism, but what kind of a substance is this, and why does it have this twofold form of manifestation? These are questions, he replies, beyond the reach of our knowledge. We can simply make a statement which seems to be required by the facts, namely, that the same thing which lives, grows, and takes on form in the outward world, apprehends itself inwardly as thinking, feeling, and willing. No opinion is thereby ventured as to whether mind or matter is the more original form of existence. By no means is metaphysical speculation upon this question excluded. The hypothesis of identity (for so Professor Höffding terms it) is consistent with philosophical idealism and also with the view that the innermost nature of being is not identical with consciousness. He simply claims for it that it is the most natural conclusion with regard to the relation between two empirical sciences, physiology and psychology. These sciences, according to the hypothesis, treat of the same material viewed from two different sides, and there can be no more conflict between them than between one person who looks on the convex side of a circle and another who looks on the concave side (to borrow an illustration used by Fechner).
On another occasion I may give my own views, and content myself now with saying that I have followed with the greatest interest and with much (if not unlimited) satisfaction the treatment of the subject at the hands of the genial, large-minded Danish professor.
W. M. SALTER.
LITERARY CORRESPONDENCE.
FRANCE.
The work of M. FOUILLÉE which I announced in my last communication (to your other magazine), bears the title of L'Evolutionnisme des Idées-Forces. It is a voluminous work; and it contains a great many things—perhaps too many. We have from M. Fouillée, the promise of a constructive work—La Psychologie des Idées-Forces, in two volumes; but his present book is chiefly devoted to the labor of demolition. As contemporaneous psychology has its weak sides, and as M. Fouillée is a skilful critic, you may imagine that his attacks upon Wundt, Herbert Spencer, Taine, Ribot, W. James, and numbers of others, both living and dead, are conducted with spirit. The successful fulfilment of the task he has set himself would necessitate the ruin of the hypothesis, avowed or concealed, that has supported psychological research as well as furnished occasional excellent conclusions; for it is the aim of M. Fouillée to overthrow what he has ingeniously termed the theory of "idea-reflexes," and the place once cleared, to substitute for it the theory of "idea-forces."