Mass, time, magnetic moment, the unconscious: we have grown up with these symbolic concepts, so that we are startled to be told that man had once to create them for himself. He had indeed, and he has: for mass is not an intuition in the muscle, and time is not bought ready-made at the watchmaker's.

Part 2: "The Habit of Truth", §5 (p. 35) - Science and Human Values (1956, 1965)