Logical consequences are the scarecrows of fools and the beacons of wise men.

Not far from the invention of fire we must rank the invention of doubt.

Science ... warns me to be careful how I adopt a view which jumps with my preconceptions, and to require stronger evidence for such belief than for one to which I was previously hostile. My business is to teach my aspirations to conform themselves to fact, not to try and make facts harmonize with my aspirations.

Genius, as an explosive power, beats gunpowder hollow.

It is not to be forgotten that what we call rational grounds for our beliefs are often extremely irrational attempts to justify our instincts.

Every great advance in natural knowledge has involved the absolute rejection of authority.

To persons uninstructed in natural history, their country or seaside stroll is a walk through a gallery filled with wonderful works of art, nine-tenths of which have their faces turned to the wall.