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.
PlatoFor the poet is a light winged and holy thing, and there is no invention in him until he has been inspired and is out of his senses and the mind is no longer with him. When he has not attained this state he is powerless and unable to utter his oracles.
Plato