[Footnote 34: Let us remark, in passing, how badly nature has organised the system of communication between thinking beings. In what we experience we have nothing in common with our fellows; each one experiences his own sensations and not those of others. The only meeting point of different minds is found in the inaccessible domain of the _noumena._] [Footnote 35: E. RABIER, _Lecons de Philosophie_, "Psychologie," p. 33.] [Footnote 36: This seems to have been the opinion of Democritus. The modern doctrine of radiation from the human body, if established, would go nearly as far as the supposition in the text. Up till now, however, it lacks confirmation.--ED.] [Footnote 37: I am compelled, much against my will, to use throughout this passage an equivocal expression, that of "mental law," or law of consciousness, or psychological law. I indicate by this the laws of contiguity and of similarity; as they result from the properties of the images, and as these are of a material nature, they are really physical and material laws like those of external nature. But how can all these laws be called physical laws without running the risk of confusing them one with the other?] [Footnote 38: _Finality_ seems to be here used in the sense of the doctrine which regards perfection as the final cause of existence.--ED.] [Footnote 39: See a very interesting article by E. GOBLOT, "La Finalite sans Intelligence," _Revue de Metaphysique_, July 1900.] BOOK III THE UNION OF THE SOUL[40] AND THE BODY CHAPTER I THE MIND HAS AN INCOMPLETE LIFE The problem of the union of the mind and the body is not one of those which present themselves in pure speculation; it has its roots in experimental facts, and is forced upon us by the necessity of explaining observations such as those we are about to quote. The force of our consciousness, the correctness of our judgments, our tempers and our characters, the state of health of our minds, and also their troubles, their weaknesses, and even their existence, are all in a state of strict dependence on the condition of our bodies, more precisely with that of our nervous systems, or, more precisely still, with the state of those three pounds of proteid substance which each of us has at the back of his forehead, and which are called our brains. This is daily demonstrated by thousands upon thousands of observations. The question is to know how this union of the body with the consciousness is to be explained, it being assumed that the two terms of this union present a great difference in their nature. The easier it seems to demonstrate that this union exists, the more difficult it appears to explain how it is realised; and the proof of this difficulty is the number of divergent interpretations given to it. Were it a simple question of fact, the perpetual discussions and controversies upon it would not arise.