The said truth is that it is the greatest happiness of the greatest number that is the measure of right and wrong.
(Jeremy Bentham (1748-1832), British philosopher, political theorist, jurist. repr. (1948). Fragment of Government (1776).
The formula was repeated with minor variations in Bentham's later writings. He ascribed the originator of this definition to be either clergyman and scientist Joseph Priestley (1733-1804) or Italian legal reformer Cesare Beccaria (1738-1794), though the Scottish philosopher Francis Hutcheson had said much the same in his Inquiry into the Original of our Ideas of Beauty and Virtue (1725): "That action is best which procures the greatest happiness for the greatest numbers.")