The solution of the question is not so difficult to find. In the first place, our knowledge of the concomitance of brain-process and consciousness, or at least of the constant uniformity of this concomitance, is only comparatively recent. Further, this knowledge is not given us immediately, but is the conclusion of a process of reasoning. While such concomitance as we immediately perceive—the concomitance of certain impressions on one sense with certain other impressions upon other senses—appears to us so natural as to need no comment, the newness and mediate nature of our knowledge of this other concomitance incline us to regard it as strange and needing some especial "explanation." While the concomitant impressions upon the senses, wherever they are constant, become united in our conception to a single whole, we fail to unite the elements of this mediately known concomitance to such a whole; doubtless, however, if a perception of all the details of our own brain-activity were the invariable accompaniment of thought, we should thus unite them. We can no more "explain" why the two activities are concomitant, except as we show it to be a fact and analyze it into its elements, than we can show why just Prussian blue should be the characteristic of one chemical compound and the green of plant-life of another, why the connection of the colors should not be the reverse. The importance we accord the physiological accompaniments of mental process is partly accounted for by the significance which attaches to more recent knowledge as constituting scientific progress; in the effort to bring together in our conception the two elements of consciousness and brain-action, to whose association we are not accustomed by immediate perception, we are led to lay especial weight upon the facts of recent discovery, which are connected with so great advance in science and have done away with so many superstitions. And, finally, in the rebound from the old superstitions, the tendency is to exaggerated views in the opposite direction. The attempt to correct spiritualistic ideas of a soul superior to the rest of nature and no part of it has resulted in materialism. And by the physiological basis we now think to "explain" the facts of psychology. "Notable enough," says Carlyle, "wilt thou find the potency of Names; Witchcraft, and all manner of Spectre-work and Demonology, we have now named Madness, and Diseases of the Nerves. Seldom reflecting that still the new question comes upon us: What is Madness, what are Nerves? Ever, as before, does Madness remain a mysterious-terrific, altogether infernal boiling-up of the Nether Chaotic Deep, through this fair-painted Vision of Creation, which swims thereon, which we name the Real. Was Luther's Picture of the Devil less a Reality, whether it were formed within the bodily eye or without it?"
If the connection of physiological and psychological processes requires "explanation," beyond that of analysis, why should we not feel ourselves equally required to explain, in like manner, the connection of light with heat and sound, and form with color? Why is it more comprehensible that the ball can be at the same time round to my touch and red or gray to my eye, and that the rose can both smell sweet and be yellow in tint? Why should we, in this particular instance, make such a strenuous effort to find reasons which can never be given in this case any more than in the others, and which we do not, moreover, demand in the others? Why cannot we accept the simple fact of concomitance in this case also? Our attempts to show the reason of brain-activity by means of mind-activity, or, vice versa, to explain mental activity as caused by, and dependent upon, physiological activity, must end equally in failure, in a one-sided dogmatism. It is the concomitance of the two, to the thought of which we are not yet used, that thwarts us. And yet Zeno, the sceptic, found as great difficulties in sequence, and proved, to his satisfaction and that of his followers, the utter impossibility of many things which we accept as simple facts without troubling ourselves to solve his problems.
We have seen that any explanation of facts beyond analysis, except as we assume some transcendental intuition, is impossible. The search for some further explanation embodies the last remnant of the idea of some special separate agent behind each single event and process, with which early superstition was animated. Driven by the gradual spread of knowledge to more and more obscure details in concomitance, and to ever greater distance of time in sequence, it has reached the final shadows of the one, and the furthest ends of evolution, whither thought seldom travels, in the other. That we expect other explanation than analysis, or read into analysis more than its real worth, is the result of an indistinctness and confusion in our thought, which has not yet lost the habit of infusing into generalizations and abstractions a vitality of their own apart from reality. We continually hope and strive for some explanation that shall give us more than nature, and yet, strange to say, we endeavor to found our theories in and on nature. We acknowledge the scientific truth of the indestructibility of matter and force, the constancy of their sum, and yet we nevertheless continue to construct our many-storied theories of causes and essences, failing to notice that we are bringing all our concepts from a time when the equivalence of results and conditions, of results and their factors, was not yet comprehended.
FOOTNOTES:
[131] See Part I. p. 107 et seq.
[132] "Sittlichkeit und Darwinismus," p. 363. See also, however, the "Grundlegung der Ethik," p. 289.
[133] "Problems of Life and Mind," Ser. I. Vol. I. pp. 308, 309.
[134] "Die Entwicklungsgeschichte des Weltalls," pp. 352 et seq.