Certainty and similar states of ‘knowing what we know’ arise out of involuntary brain mechanisms that, like love or anger, function independently of reason.

Hope and patience are two sovereign remedies for all, the surest reposals, the softest cushions to lean on in adversity.

Our mental limitations prevent us from accepting our mental limitations.

Employment, which Galen calls 'Nature's Physician,' is so essential to human happiness that indolence is justly considered as the mother of misery.

Every man hath a good and a bad angel attending on him, all his life long.

Certainty is not biologically possible. We must learn (and teach our children) to tolerate the unpleasantness of uncertainty. Science has given us the language and tools of probabilities. We have methods for analyzing and ranking opinion according to their likelihood of correctness. That is enough.

We want to be known for having original ideas, inspired hunches, and gut feelings that make a difference. Indeed, a "well-honed sixth sense"' is considered a measure of the good clinician. But being a good doctor also requires sticking with the best medical evidence, even if it contradicts your personal experience. We need to distinguish between gut feeling and testable knowledge, between hunches and empirically tested evidence.