Our personality, says the Alexandrian philosopher, cannot be a property of the body, for this is composed of parts, and is in a state of perpetual flux. A man’s self, then, is his soul; and the soul cannot be material, for the ultimate elements of matter are inanimate, and it is inconceivable that animation and reason should result from the aggregation of particles which, taken singly, are destitute of both; while, even were it possible, their disposition in a certain order would argue the presence of an intelligence controlling them from without. The Stoics themselves admit the force of these considerations, when they attribute reason to the fiery element or vital breath by which, according to them, all things are shaped. They do, indeed, talk about a certain elementary disposition as the principle of animation, but this disposition is either identical with the matter possessing it, in which case the difficulties already mentioned recur, or distinct from it, in which case the animating principle still remains to be accounted for. Again, to suppose that the soul shares in the changes of the body is incompatible with the self-identity which memory reveals. To suppose that it is an extended substance is incompatible with its simultaneous presence, as an indivisible whole, at every point to which its activity reaches; as well as with the circumstance that all our sensations, though received through different organs, are referred to a common centre of consciousness. If the sensorium is a fluid body it will have no more power of retaining impressions than water; while, if it is a solid, new impressions will either not be received at all, or only when the old impressions are effaced.