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.

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

Our mental limitations prevent us from accepting our mental limitations.

Ignorance is the Mother of Devotion.

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

Good science requires distinguishing between "felt knowledge" and knowledge arising out of testable observations. "I am sure" is a mental sensation, not a testable conclusion. Put hunches, gut feelings, and intuitions into the suggestion box. Let empiric methods shake out the good from bad suggestions.

Tobacco, divine, rare, superexcellent tobacco, which goes far beyond all the panaceas, potable gold, and philosophers stones, a sovereign remedy to all diseases but as it is commonly abused by most men, which take it as tinkers do ale, 'Tis a plague, a mischief, a violent purger of goods, lands, health; hellish, devilish and damned tobacco, the ruin and overthrow of body and soul.