Letter 58 — On Being (§23)

“This is just what Heraclitus says: “We go down twice into the same river, and yet into a different river.” For the stream still keeps the same name, but the water has already flowed past. Of course this is much more evident in rivers than in human beings. Still, we mortals are also carried past in no less speedy a course; and this prompts me to marvel at our madness in cleaving with great affection to such a fleeting thing as the body, and in fearing lest some day we may die, when every instant means the death of our previous condition. Will you not stop fearing lest that may happen once which really happens every day?”