The difference, so observable in men's understandings and parts, does not arise so much from their natural faculties, as acquired habits.
John LockeSet the mind to work, and apply the thoughts vigorously to the business, for it holds in the struggles of the mind, as in those of war, that to think we shall conquer is to conquer.
John LockeThe thoughts that come often unsought, and, as it were, drop into the mind, are commonly the most valuable of any we have.
John Locke