Between the indivisible Being that is always the same and the divisible Being that comes to be in the case of bodies he compounded a third 25 form of Being from both. (35a1–4)

Introduction

First, it is necessary to (1) state the reason why Plato provides a genesis of the soul when its origins are ungenerated according to him. Next, it is requisite to (2) divide the whole psychogenesis in respect of the manner in which it takes place; (3) to indicate the sense in which the soul is an intermediate; (4) to speak about these genera from which both the soul and other things have been established; (5) we must undertake to say how mixing of these kinds takes place in the case of soul; (6) to explain what sort of thing the divisible and indivisible kinds of Being are; (7) to make the individual words of Plato's text understandable and show that they are entirely consistent with what was said before. Should we come to be able to apprehend these things in words (tôi logôi), then we will have realised the goal of the present inquiry in the manner that is consonant with our abilities.

Why Plato speaks as if the soul was generated when its origins are ungenerated

Theophrastus’ objection

Let us therefore begin from the first point because some of the ancient philosophers rebuke Plato and say: ‘he incorrectly searches for a principle of a principle and a genesis of an ungenerated thing. For if we look for the causes of the things that are primary and set our minds on the genesis of things that are self-subsistent (authypostatos), we shall fail to see that we shall be going on to infinity and have no end of our inquiries. For just as the person who thinks that all things are capable of demonstration actually does away with demonstration itself, so too the person who seeks after causes in this manner entirely overturns all the existent things and the order in which they they proceed from some definite principle’ (Fortenbaugh (1992), fr. 159).