Quantities of pain or pleasure may be regarded as magnitudes having the same definiteness as tons of pig iron, barrels of sugar, bushels of wheat, yards of cotton, or pounds of wool; and as political economy seeks to ascertain the conditions under which these commodities may be produced with the greatest efficiency–so the economy of happiness seeks to ascertain the conditions under which happiness, regarded as a commodity, may be produced with the greatest efficiency.

James MacKaye, The Economy of Happiness, Boston, 1906, p. 183-184