Nature is always too strong for principle. - David Hume

All beliefs about matters of fact or real existence are derived merely from something that is present to the memory or senses, and a customary association of that with some other thing.

Hume argued powerfully that human reason is fundamentally similar to that of the other animals, founded on instinct rather than quasi-divine insight into things.

When we think back on our past sensations and feelings, our thought is a faithful mirror that copies its objects truly; but it does so in colours that are fainter and more washed-out than those in which our original perceptions were clothed.