and which comprehends them both in its infinity, must have joined them in my soul, and given me an idea of a nature entirely different from that which thinks in me. SECT. LXII. The Idea of the Unity proves that there are Immaterial Substances; and that there is a Being Perfectly One, who is God. As for units, some perhaps will say that I do not know them by the bodies, but only by the spirits; and, therefore, that my mind being one, and truly known to me, it is by it, and not by the bodies, I have the idea of unity. But to this I answer. It will, at least, follow from thence that I know substances that have no manner of extension or divisibility, and which are present. Here are already beings purely incorporeal, in the number of which I ought to place my soul. Now, who is it that has united it to my body? This soul of mine is not an infinite being; it has not been always, and it thinks within certain bounds. Now, again, who makes it know bodies so different from it? Who gives it so great a command over a certain body; and who gives reciprocally to that body so great a command over the soul? Moreover, which way do I know whether this thinking soul is really one, or whether it has parts? I do not see this soul. Now, will anybody say that it is in so invisible, and so impenetrable, a thing that I clearly see what unity is? I am so far from learning by my soul what the being One is, that, on the contrary, it is by the clear idea I have already of unity that I examine whether my soul be one or divisible.