The Wealth of Nations (Illustrated)

by Adam Smith

Labour, therefore, it appears evidently, is the only universal, as well as the only accurate, measure of value, or the only standard by which we can compare the values of different commodities, at all times, and at all places. We cannot estimate, it is allowed, the real value of different commodities from century to century by the quantities of silver which were given for them. We cannot estimate it from year to year by the quantities of corn. By the quantities of labour, we can, with the greatest accuracy, estimate it, both from century to century, and from year to year. From century to century, corn is a better measure than silver, because, from century to century, equal quantities of corn will command the same quantity of labour more nearly than equal quantities of silver.