This section, which does not readily admit of summary, is chiefly concerned with showing that there are certain immanent characters (‘forms’) which exclude, or will not admit into themselves, one or other of a pair of opposites. The whole argument prepares us, by means of general principles and analogies, for the next section, where it will be asserted that soul will not admit the character ‘dead’.

[At this point Phaedo's narrative is once more interrupted by Echecrates, but only for a few lines.]

Ech. Upon my word, Phaedo, they had good reason to say so. As I see it, Socrates made matters wonderfully clear even to a feeble intelligence.

Phaedo. Just so, Echecrates: that is what everyone there thought.

Ech. As do we who were not there, your present audience. But how did the conversation proceed?

Phaedo. It was like this, I think. When Socrates had gained their assent, and it was agreed that every Form was a real existent, and that other things bore their names by virtue of participating in those Forms, he then put this question:

‘If’, he said, ‘that is your view, then when you say that Simmias is taller than Socrates and shorter than Phaedo, are you not saying that both tallness and shortness are in Simmias?’

‘Yes, I am.’

'But of course you admit that the words “Simmias overtops Socrates” do not express the truth of the matter.