As it is in the body, so it is in the mind; practice makes it what it is, and most even of those excellencies, what are looked on as natural endowments, will be found, when examined into more narrowly, to be the product of exercise, and to be raised to that pitch, only by repeated actions.
John LockeProbability is a kind of penance, which God made, suitable, I presume to that state of mediocrity and probationership he has been pleased to place us in here; wherein, to check our over-confidence and presumption, we might, by every day's experience, be made sensible of our short-sightedness, and liableness to error.
John Locke