He now goes on speaking to his friends during that fatal day at great length, setting forth other arguments in favor of the immortality of the soul. Finally he comes to the argument which he applies to the soul, that magnitude cannot admit its contrary, but that one retires when the other approaches. At this point he is interrupted by one who remembers his former position. Plato relates:
Then some one of those present (but who he was I do not clearly recollect) when he heard this, said, "In the name of the gods, was not the very contrary of what is now asserted laid down in the previous part of the discussion, that the greater is produced from the less and the less from the greater, and this positively was the mode of generating contraries from contraries?" Upon which Socrates said ... "... 'Then it was argued that a contrary thing was produced from a contrary; but now, that contrary itself can never become its own contrary'.... But observe further if you will agree with me in this. Is there anything you call heat and cold?"
"Certainly."
"The same as snow and fire?"
"Assuredly not."
"Is heat, then, something different from fire, and cold something different from snow?"
"Yes."
"But this I think is evident to you, that snow while it is snow can never, having admitted heat, continue to be what it was, snow and hot; but on the approach of heat will either give way to it or be destroyed."
"Certainly so."
"And fire, on the other hand, on the approach of cold, must either give way to it or be destroyed; nor can it ever endure, having admitted cold, to continue to be what it was, fire and cold.... Such I assert to be the case with the number 3 and many other numbers. Shall we not insist that the number 3 shall perish first ... before it would endure while it was yet 3 to become even?... What then? what do we now call that which does not admit the idea of the even?"