Stephen Jay Gould

Certainty is both a blessing and a danger. Certainty provides warmth, solace, security–an anchor in the unambiguously factual events of personal observations and experience. But certainty is also a great danger, given the notorious fallibility–and unrivaled power–of the human mind… Of course we must treat the human mind with respect–for nature has fashioned no more admirable instrument. But we must also struggle to stand back and to scrutinize our own mental certainties. This last line poses an obvious paradox, if not an outright contradiction–and I have no resolution to offer. Yes, step back and scrutinize your own mind. But with what?