These three quotations show very conclusively that their authors thought they could establish the heterogeneity of the two phenomena by opposing matter to sensation. It must be recognised that they have fallen into a singular error; for matter, whatever it may be, is for us nothing but sensation; matter in motion, I have often repeated, is only a quite special kind of sensation; the organic matter of the brain, with its whirling movements of atoms, is only sensation. Consequently, to oppose the molecular changes in the brain to the sensation of red, blue, green, or to an undefined sensation of any sort, is not crossing a gulf, and bringing together things which cannot be compared, it is simply comparing one sensation to another sensation. There is evidently something equivocal in all this; and I pointed this out when outlining and discussing the different theories of matter. It consists in taking from among the whole body of sensations certain of them which are considered to be special, and which are then invested with the privilege of being more important than the rest and the causes of all the others. This is about as illegitimate as to choose among men a few individuals to whom is attributed the privilege of commanding others by divine right. These privileged sensations which belong to the sight, the touch, and the muscular sense, and which are of large extent, are indeed extensive. They have been unduly considered as objective and as representing matter because they are better known and measurable, while the other sensations, the unextensive sensations of the other senses, are considered as subjective for the reasons that they are less known and less measurable: and they are therefore looked on as connected with our sensibility, our Ego, and are used to form the moral world. We cannot subscribe to this way of establishing the contrast between matter and thought, since it is simply a contrast between two categories of sensations, and I have already asserted that the partitioning-out of sensations into two groups having different objective values, is arbitrary. FOOTNOTES: [Footnote 15: CH. RENOUVIER et L. PRAT, _La Nouvelle Monadologie_, p. 148.] [Footnote 16: An American author, MORTON PRINCE, lately remarked this: _Philosophical Review_, July 1904, p. 450.] [Footnote 17: This FLOURNOY recently has shown very wittily. See in _Arch. de Psychol._, Nov. 1904, his article on Panpsychism.] [Footnote 18: This extract, together with the two subsequent, are borrowed from an excellent lecture by FLOURNOY, on _Metaphysique et Physiologie_. Georg: Geneva, 1890.] CHAPTER III DEFINITION OF THE IMAGE Going on with our inventory, after sensations come images, ideas, and concepts; in fact, quite a collection of phenomena, which, are generally considered as essentially psychological.