The Six Books of Proclus on the Theology of Plato, Volume 2

For no body is naturally adapted to revert to itself. For if that which is converted to any thing is conjoined with that to which it is converted, it is evident that all the parts of the body which is converted to itself, will be conjoined with all the parts. For this it is for a thing to be converted to itself, when both that which is converted, and that to which it is converted, become one. This however is impossible in body, and in short, in all partible things. For the whole of that which is partible is not conjoined with the whole, on account of the separation of the parts, some of which are situated differently from others. No body therefore, is naturally adapted to revert to itself, so as that the whole may be converted to the whole. Hence if there is any thing which has the power of reverting to itself, it is incorporeal and impartible.