Huckleberry Finn is not irrational in being unmotivated to follow his explicit judgments of rightness and wrongness. Philosophers have previously judged Huck to be irrational, subject to weakness of will, in being unable to act on his moral judgment. But their interpretation rests on incorrect analyses of weak will and of the emotions on which Huck does act. I also argue that such emotion based motivation is not of the kind that could be rationally required. The character of Huckleberry Finn therefore implies that rational agents need not be morally motivated.