Applying the principle just established, Socrates argues that soul always ‘brings up’ life into that which it ‘occupies’ (as an immanent form), and excludes death. Hence we have proved that ‘soul is deathless’. But this is not, in his view, the same as proving that it is indestructible or imperishable; hence the rest of the section consists mainly in an attempt to establish this further proposition, and the imperishability of each individual soul is proclaimed at the end of 106E.

Some doubt still lingers in the mind of Simmias, despite his assent to the foregoing argument; whereupon Socrates recommends a further examination of ‘the original assumptions’.

'Well now, go back to the beginning, will you? And please don't meet my questions with that safe answer we spoke of, but copy my example. I say that because the course of our argument has led me to discern a different kind of safety from that which I mentioned originally. Thus, if you were to ask me what must come to be present in a thing's body to make it hot, I should not give you that safe, stupid answer “heat”, but a cleverer one now at my disposal, namely “fire”. Again, if you ask what must come to be present in a body to make it sick, I shall not say “sickness” but “fever”. Similarly, what must be present in a number for it to be odd? Not oddness, but a unit; and so on.