"I act with complete certainty. But this certainty is my own."

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This is what it is to be human: to see the essential existential futility of all action, all striving -- and to act, to strive. This is what it is to be human: to reach forever beyond your grasp. This is what it is to be human: to live forever or die trying. This is what it is to be human: to perpetually ask the unanswerable questions, in the hope that the asking of them will somehow hasten the day when they will be answered. This is what it is to be human: to strive in the face of the certainty of failure. This is what it is to be human: to persist.

— Spider Robinson