When a thoughtful human being has overcome incentives to vice and is aware of having done his bitter duty, he finds himself in a state that could be called happiness, a state of contentment and peace of mind in which virtue is its own reward.
Immanuel KantHere I shall add that the concept of change, and with it the concept of motion, as change of place, is possible only through and in the representation of time. & Motion, for example, presupposes the perception of something movable. But space considered in itself contains nothing movable; consequently motion must be something which is found in space only through experience -in other words, is an empirical datum.
Immanuel Kant