Permit me to repeat the statement that there is no reasoning here along the "high-priori" road of inconceivability. I see no more inconceivability in supposing that a brain-change should be followed by a thought than that it should be followed by an increased secretion. The thing needed is, to know the fact in the case. Are brain-changes transformed into consciousness, or does the soul, on occasion of these changes, respond in its peculiar language?
The brain-changes, as we know them and must know them, consist of attractions, repulsions, motions, and co-ordinations of the brain-particles. These, according to the physiological materialist and the young physician, are transformed into states of consciousness, which states are not material changes, but separated from them by a chasm "intellectually impassable." It has been wisely said that the position which a thorough-going scientific evolution ought to defend is this: thoughts, feelings, volitions, any and all states of consciousness, have no existence for physical science. Indeed, the annoyance caused by consciousness as a useless "surplusage" is nowhere more strikingly illustrated than in the following passage from Professor Huxley's paper "On the Hypothesis that Animals are Automata." The author writes: "Though we may see reason to disagree with Descartes's hypothesis that brutes are unconscious machines, it does not follow that he was wrong in regarding them as automata. We believe, in short, that they are machines, one part of which (the nervous system) not only sets the rest in motion and co-ordinates its movements in relation with changes in surrounding bodies, but is provided with special apparatus, the function of which is the calling into existence of those states of consciousness which are termed sensations, emotions, ideas. It may be assumed, then, that molecular changes in the brain are the causes of all the states of consciousness in brutes. Is there any evidence that these states of consciousness may, conversely, cause those molecular changes which give rise to muscular motion? I see no such evidence. The frog walks, hops, swims, quite as well without consciousness as with it, and if a frog, in his natural state, possesses anything corresponding with what we call volition, there is no reason to think that it is anything but a concomitant of molecular changes in the brain which form part of the series involved in the production of motion. The consciousness of brutes would appear to be related to the mechanism of their body as a collateral product of its working, and to be as completely without any power of modifying that working as the steam-whistle which accompanies the work of a locomotive-engine is without influence upon its machinery. Their volition, if they have any, is an emotion (?) indicative of physical changes, not a cause of such changes. It is quite true that this reasoning holds equally good of men, and therefore that all states of consciousness in us, as in them, are immediately caused by molecular changes of the brain-substance. It seems to me that, in men as in brutes, there is no proof that any state of consciousness is the
