All men are liable to error, and most men are in many points, by passion and interest, under temptation to it. If we could but see the secret motives that influenced the men of name and learning in the world, and the leaders of parties, we should not always find that it was the embracing of truth for its own sake, that made them espouse the doctrines they owned and maintained.
Let ever so much probability hang on one side of a covetous man’s reasoning, and money on the other; it is easy to forsee which will outweigh. Earthly minds, like mud walls resist the strongest batteries: and though, perhaps, sometimes the force of a clear argument may make some impression, yet they nevertheless stand firm, and keep out the enemy, truth, that would captivate or disturb them… Quod volumus, facile credimus; what suits our wishes, is forwardly believed.
~ John Locke, quoted in Epistemology: Becoming Intellectually Virtuous, by W. Jay Wood.