just price

The just price is a theory of ethics in economics that attempts to set standards of fairness in transactions. With intellectual roots in ancient Greek philosophy, it was advanced by Thomas Aquinas based on an argument against usury, which in his time referred to the making of any rate of interest on loans. It gave rise to the contractual principle of laesio enormis. Unjust price: a kind of fraud The argument against usury was that the lender was receiving income for nothing, since nothing was actually lent, rather the money was exchanged. Furthermore, a dollar can only be fairly exchanged for a dollar, so asking for more is unfair. Aquinas later expanded his argument to oppose any unfair earnings made in trade, basing the argument on the Golden Rule. The Christian should "do unto others as you would have them do unto you", meaning he should trade value for value. Aquinas believed that it was specifically immoral to raise prices because a particular buyer had an urgent need for what was being sold and could be persuaded to pay a higher price because of local conditions: If someone would be greatly helped by something belonging to someone else, and the seller not similarly harmed by losing it, the seller must not sell for a higher price: because the usefulness that goes to the buyer comes not from the seller, but from the buyer's needy condition: no one ought to sell something that doesn't belong to him. — Summa Theologiae, 2-2, q. 77, art. 1 Aquinas would therefore condemn practices such as raising the price of building supplies in the wake of a natural disaster. Increased demand caused by the destruction of existing buildings does not add to a seller's costs, so to take advantage of buyers' increased willingness to pay constituted a species of fraud in Aquinas's view.