...Scepticism is an exercise, not a life; it is a discipline fit to purify the mind of prejudice and render it all the more apt, when the time comes, to believe and to act wisely; and meantime the pure sceptic need take no offence at the multiplicity of images that crowd upon him, if he is scrupulous not to trust them and to assert nothing at their prompting. Scepticism is the chastity of the intellect, and it is shameful to surrender it too soon or to the first comer: there is nobility in preserving it coolly and proudly through a long youth, until at last, in the ripeness of instinct and discretion, it can be safely exchanged for fidelity and happiness.

— George Santayana, Scepticism and Animal Faith