Simmias, after some general reflexions on the right attitude to problems of this sort, proceeds to elaborate a theory of the soul as an ‘attunemen’ (ἁρμονία) of the bodily constituents. Then Cebes argues that, despite the fact that any soul endures longer than any body, we cannot be sure that it can outlast the whole series of bodies which (as he contends) succeed one another throughout a man's lifetime, any more than a weaver can outlast the whole series of cloaks that he weaves and wears.

‘Thank you’, said Simmias. 'Then I will tell you my difficulty, and Cebes here in his turn will say what he finds unacceptable in the argument. What I feel, Socrates—and perhaps you feel the same yourself—is that certainty of knowledge on matters like this is either impossible of attainment in this life or very difficult; nevertheless he would be a very feeble-spirited person who failed to subject current opinions about them to the closest scrutiny; one should not desist until he has worn himself out in a thoroughgoing inquiry. In fact we ought to achieve one of two things: either to find for ourselves, or learn from some other, the truth about these matters: or else, if that is impossible, to seize upon the best and most irrefutable doctrine that mankind can offer, and take it as a raft on which to accomplish the dangerous voyage of life; unless indeed we can come to harbour in a safer and less dangerous fashion, resting on the firmer support of doctrine divinely revealed.