John Stuart Mill,
Principles of Political Economy
(1871)
“ In a state of society, however, in which the industrial system is entirely founded on purchase and sale, each individual, for the most part, living not on things in the production of which he himself bears a part, but on things obtained by a double exchange, a sale followed by a purchase—the question of Value is fundamental. Almost every speculation respecting the economical interests of a society thus constituted, implies some theory of Value: the smallest error on that subject infects with corresponding error all our other conclusions ”
