It will further be allowed, that there are certain material particles which may become vehicles for either or both of these kinds of sensations, while there are others which have the power of producing one only. Gold, silver, and platinum are substances which may become the vehicle of common impressions, but not of peculiar impressions, since they do not occur in our brains. Phosphorus, on the other hand, is a substance which may become the vehicle of either kind. When we burn a piece of phosphorus in a lecture-room it is the vehicle of a common impression, while the phosphorus in our brain is the vehicle of a peculiar impression. Now there is a very noteworthy difference between portions of phosphorus playing these two parts. When phosphorus is in the common state, we can experiment upon it and investigate its properties, but this we cannot do when it exists in the brain in its peculiar state. The assertion, therefore, that phosphorus and its allied particles, whose motions and positions are accompanied by individual consciousness, are nevertheless, when in this state, essentially the same as they are in the ordinary state, appears to us to be altogether without foundation. We have no right thus to argue from the one state to the other. For that most peculiar and interesting condition of phosphorus and other matter in which it is intimately connected with the production of individual consciousness, and where some peculiarity of properties or behaviour due to this connection might most warrantably be expected, is the very thing which we cannot investigate. To say therefore that the living brain consists of particles of phosphorus, carbon, etc., _such as we know them in the common state_, and that when the particles of the brain have, in consequence of the operation of physical forces, a certain position and motion, then individual consciousness follows, is to assign a peculiar relation between the brain-particles and such consciousness for which we have no scientific warrant. 57. Allied to this assumption there is another in the materialistic argument as we have stated it. If in the body there be no other material than the visible particles, and in the brain no other material than a certain quantity of phosphorus and other things, such as we know them in the common state, and if individual consciousness depends upon the structural presence of these substances in the body and brain, then when this structure falls to pieces there are of course reasonable grounds for supposing that such consciousness has entirely ceased. But it is the object of this volume to exhibit various scientific reasons for believing that there is something beyond that which we call the visible universe; and that individual consciousness is in some mysterious manner related to, or dependent upon, the interaction of the seen and unseen.