The position of John Tyndall is well understood. It was avowed in 1860 in the _Saturday Review_; again in his address to the Mathematical and Physical Section of the British Association in 1868, wherein he declared that "The passage from the physics of the brain to the corresponding facts of consciousness is unthinkable. Granted that a thought and a definite molecular action in the brain occur simultaneously, we do not possess the organ, nor, apparently, any rudiment of the organ, which would enable us to pass by a process of reasoning from the one phenomenon to the other. They appear together, but we do not know why." In 1875, reviewing Martineau in the _Popular Science Monthly_ for December, Tyndall calls attention to these declarations, and quotes other language of his own to the same purpose: "You cannot satisfy the understanding in its demand for logical continuity between molecular processes and the phenomena of consciousness. This is a rock on which materialism must inevitably split whenever it pretends to be a complete philosophy of the human mind." Mr. John Fiske, a disciple of Herbert Spencer, and an exceedingly able expositor of the philosophy of which Spencer is the acknowledged chief, makes assertions equally positive:[6] "However strict the parallelism may be within the limits of our experience, between the phenomena of the mind, and the segment of the circle of motions, the task of transcending or abolishing the radical antithesis between the phenomena of mind and the phenomena of matter, must always remain an impracticable task; for, in order to transcend or abolish this radical antithesis, we must be prepared to show how a given quantity of molecular motion in nerve tissue can be transformed into a definable amount of ideation or feeling. But this, it is quite safe to say, can never be done." [6] Outlines of Cosmic Philosophy, Vol. II., p. 442. There are of course, distinguished names on the other side. The work on "Intelligence," by Mr. Taine, which Mr. Mill warmly commends as the "the first serious effort (in France) to supply the want of a better than the official psychology," cannot be wisely overlooked by any one interested in this problem. Taine objects to Tyndall's statement of the problem, declares that by approaching it from another point, it is soluble, and frankly undertakes to solve it.[7] [7] On Intelligence, Book III., chap. I.