Entropy is not about speeds or positions of particles, the way temperature and pressure and volume are, but about our lack of information. - Hans Christian von Baeyer

To put it one way, a collection of Shakespeare's plays is richer than a phone book that uses the same number of letters; to put it another, the essence of information lies in the relationships among bits, not their sheer number.

Numbers instill a feeling for the lie of the land, and furnish grist for the mathematical mill that is the physicist's principal tool.

Paradox is the sharpest scalpel in the satchel of science. Nothing concentrates the mind as effectively, regardless of whether it pits two competing theories against each other, or theory against observation, or a compelling mathematical deduction against ordinary common sense.