pleasure over pain, or of pain over pleasure, it may be true that the excess caused by the one is greater than that caused by the other. And, this being so, all actions may, theoretically at least, be arranged in a scale, starting at the top with those which cause the greatest excess of pleasure over pain; passing downwards by degrees through cases where the excess of pleasure over pain is continually smaller and smaller, until we reach those actions which cause no excess either of pleasure over pain or of pain over pleasure: then starting again with those which cause an excess of pain over pleasure, but only the smallest possible one; going on by degrees to cases in which the excess of pain over pleasure is continually larger and larger; until we reach, at the bottom, those cases in which the excess of pain over pleasure is the greatest.
The principle upon which this scale is arranged is, I think, perfectly easy to understand, though it cannot be stated accurately except in rather a complicated way. The principle is: That any action which causes an excess of pleasure over pain will always come higher in the scale either
