[Footnote 45: _Archives de Psychologie_, vol. iv. No. 14, Nov. 1904, p. 132 (article on Panpsychism).] CHAPTER III MATERIALISM AND PARALLELISM Materialism is a very ancient doctrine. It is even the most ancient of all, which simply proves that amongst the different explanations given of our double physico-mental nature, this doctrine is the easiest to understand. The origin of materialism is to be found in the beliefs of savage tribes, and is again found, very clearly defined, in the philosophy of those ancient Greeks who philosophized before Plato and Aristotle. A still stranger fact is that the thoughts of a great number of the Fathers of the Church inclined towards the philosophy of matter. Then, in the course of its evolution, there occurred a moment of eclipse, and materialism ceased to attract attention till the contemporary period in which we assist at its re-birth, Nowadays, it constitutes a powerful doctrine, the more so that it has surreptitiously crept into the thoughts of many learned men without their being clearly conscious of it. There are many physicists and physiologists who think and speak as materialists, though they have made up their minds to remain on the battle-ground of observed facts and have a holy horror of metaphysics. In a certain sense, it may be said that materialism is the metaphysics of those who refuse to be metaphysicians. It is very evident that in the course of its long history, materialism has often changed its skin. Like all knowledge, it has been subject to the law of progress; and, certainly, it would not have been of a nature to satisfy the intellectual wants of contemporary scholars, had it not stripped itself of the rude form under which it first manifested itself in the mind of primitive man. Yet what has enabled the doctrine to keep its unity through all its changes is that it manifests a deeply human tendency to cling by preference to everything visible and tangible. Whatever strikes the eyes, or can be felt by the hand, seems to us in the highest degree endowed with reality or existence. It is only much later, after an effort of refined thought, that we come to recognise an existence in everything that can be perceived in any way whatever, even in an idea. It is still later that we understand that existence is not only that which is perceived but also that which is linked logically with the rest of our knowledge. A good deal of progress has been necessary to reach this point. As I have not the slightest intention of giving even an abridged history of materialism, let us come at once to the present day, and endeavour to say in what consists the scientific form this doctrine has assumed. Its fundamental basis has not changed. It still rests on our tendency to give chief importance to what can be seen and touched; and it is an effect of the hegemony of three of our senses, the visual, the tactile, and the muscular.