by the abstract terms which he has formed to express it. The physiological materialist can never meet the demand which a proof of his belief requires, viz., that he should be able to consider the nervous system apart from consciousness before declaring it the sole cause of consciousness. All that is known of the nervous system is known through consciousness; is there, then, no importance, no necessity, for some examination of consciousness for those who would give an account of their knowledge, be its content what it may? This position, rightly understood, will vindicate my assertion that, for all forms of investigation, the need at present is a critique of knowing, a critique which shall be not simply a "Zurückgehen auf Kant" (profitable as this might prove for an understanding of his relation to materialism), but a critique which shall embody the contributions of recent years from investigators in the territories of the senses, the understanding, and the emotions.
It may be asked, Why should this appeal for consciousness come so late in the present discussion? Ought it not rather to have preceded the statement of the characteristics of consciousness, and so prevented a break in the course of thought? Such a break is, of course, undesirable; still, it is one not to be avoided, as I think, under the circumstances.
There remain for consideration certain special features of consciousness, for whose examination and estimation special entreaty was needed. This solicitation will have more force when placed in direct connection with the features themselves. The writer ventured to hope that those broader, more noticeable characteristics of consciousness which lie, as it were, upon the surface, might be left to awaken attention by their size. Not so with matters now to be brought forward. While there is no purpose to leave, even for an instant, the territory of experience, we enter a portion of that territory which, to many, will be new, and therefore, without effort against prejudice, untrue.
There are certain special facts in consciousness, i. e., certain distinctive features in each person's experience, which prevent, out and out, the acceptance of correlation as a proper account of the relations between brain and consciousness. Few would refuse to admit that sensation is a fact, yet there is danger of studying sensation with the sensation omitted.
Every sensation has four physical antecedents which, though distinct, are not different in kind from one another. This is such a preponderance of the physical that the other element is likely to go unnoticed. The physical requisites for every sensation are: 1. Some outward, exciting cause or excitation—this is physical movement, nothing else; it may be of ponderable matter or of an imponderable instrument, as light. 2. The contact of this physical condition of movement with a sensitive portion of the body. 3. The excitation--
