Discourses: Book 4 1 : 7
That is why we shall call free only those animals which do not submit to captivity, but escape by dying as soon as they are captured. So also Diogenes says somewhere: "The one sure way to secure freedom is to die cheerfully"; and to the Persian king he writes: "You cannot enslave the Athenian State any more than you can enslave the fish." "How so? Shall I not lay hold of them?" "If you do," he replies, "they will forthwith leave you and escape, like the fish. And that is true, for if you lay hold of one of them, it dies; and if these Athenians die when you lay hold of them, what good will you get from your armament?" That is the word of a free man who has seriously examined the matter, and, as you might expect, had discovered truth about it. But if you look for it where it does not exist, why be surprised if you never find it?