He is not a true man of science who does not bring some sympathy to his studies, and expect to learn something by behavior as well as by application. It is childish to rest in the discovery of mere coincidences, or of partial and extraneous laws. The study of geometry is a petty and idle exercise of the mind, if it is applied to no larger system than the starry one. Mathematics should be mixed not only with physics but with ethics; that is mixed mathematics. The fact which interests us most is the life of the naturalist. The purest science is still biographical.
Henry David ThoreauSome things are really necessaries of life in some circles, which in others are luxuries merely and in others still are entirely unknown.
Henry David ThoreauNo people ever lived by cursing their fathers, however great a curse their fathers might have been to them.
Henry David ThoreauThe way in which men cling to old institutions after the life has departed out of them, and out of themselves, reminds me of those monkeys which cling by their tails - aye, whose tails contract about the limbs, even the dead limbs, of the forest, and they hang suspended beyond the hunter's reach long after they are dead. It is of no use to argue with such men. They have not an apprehensive intellect, but merely, as it were a prehensile tail.
Henry David Thoreau