Timaeus
The Demiurge and World Soul (34c)
Timaeus: God did not likewise plan it to be younger than the body ; for, when uniting them, He would not have permitted the elder to be ruled by the younger; but as for us men, even as we ourselves partake largely of the accidental and casual, so also do our words. God, however, constructed Soul to be older than Body and prior in birth and excellence, since she was to be the mistress and ruler and it the ruled; and, He made her of the materials
Our Tutelary Spirit (5)
The answer is that very choice in the over-world is merely an allegorical statement of the Soul's tendency and temperament, a total character which it...
(5) But if the presiding Spirit and the conditions of life are chosen by the Soul in the overworld, how can anything be left to our independent action here?
The answer is that very choice in the over-world is merely an allegorical statement of the Soul's tendency and temperament, a total character which it must express wherever it operates.
But if the tendency of the Soul is the master-force and, in the Soul, the dominant is that phase which has been brought to the fore by a previous history, then the body stands acquitted of any bad influence upon it? The Soul's quality exists before any bodily life; it has exactly what it chose to have; and, we read, it never changes its chosen spirit; therefore neither the good man nor the bad is the product of this life?
Is the solution, perhaps, that man is potentially both good and bad but becomes the one or the other by force of act?
But what if a man temperamentally good happens to enter a disordered body, or if a perfect body falls to a man naturally vicious?
The answer is that the Soul, to whichever side it inclines, has in some varying degree the power of working the forms of body over to its own temper, since outlying and accidental circumstances cannot overrule the entire decision of a Soul. Where we read that, after the casting of lots, the sample lives are exhibited with the casual circumstances attending them and that the choice is made upon vision, in accordance with the individual temperament, we are given to understand that the real determination lies with the Souls, who adapt the allotted conditions to their own particular quality.
The Timaeus indicates the relation of this guiding spirit to ourselves: it is not entirely outside of ourselves; is not bound up with our nature; is not the agent in our action; it belongs to us as belonging to our Soul, but not in so far as we are particular human beings living a life to which it is superior: take the passage in this sense and it is consistent; understand this Spirit otherwise and there is contradiction. And the description of the Spirit, moreover, as "the power which consummates the chosen life," is, also, in agreement with this interpretation; for while its presidency saves us from falling much deeper into evil, the only direct agent within us is some thing neither above it nor equal to it but under it: Man cannot cease to be characteristically Man.