He who does not expect will not find out the unexpected, for it is trackless and unexplored
Men who are lovers of wisdom [i.e., philosophers] must be inquirers into many things.
Everything flows, nothing stays still.
Men who wish to know about the world must learn about it in its particular details.
All things come into being by conflict of opposites.
No one can step twice into the same river, nor touch mortal substance twice in the same condition. By the speed of its change, it scatters and gathers again.