The Greek philosopher Plato, author of the Socratic dialogues.
Apology, 4th century B.C.
Facing charges of "corrupting youth," Socrates delivered this speech — as rendered by Plato — to an Athens jury. It proved unsuccessful; he was convicted by his peers, and subsequently killed himself by swallowing hemlock. But this skillful piece of rhetoric underlines the realization that has propelled philosophy ever since: that human knowledge is woefully limited.
Best Line: "The hour of departure has arrived, and we go our ways — I to die, and you to live. Which is better God only knows."