Thinking and spoken discourse are the same thing, except that what we call thinking is, precisely, the inward dialogue carried on by the mind with itself without spoken sound.
Each living creature is said to be alive and to be the same individual - as for example someone is said to be the same person from when he is a child until he comes to be an old man. And yet, if he's called the same, that's despite the fact that he's never made up from the same things, but is always being renewed, and losing what he had before, whether it's hair, or flesh, or bones, or blood, in fact the whole body.
Is it not true that the clever rogue is like the runner who runs well for the first half of the course, but flags before reaching the goal: he is quick off the mark, but ends in disgrace and slinks away crestfallen and uncrowned. The crown is the prize of the really good runner who perseveres to the end.
He who is only an athlete is too crude, too vulgar, too much a savage. He who is a scholar only is too soft, to effeminate. The ideal citizen is the scholar athlete, the man of thought and the man of action.