Thomas Aquinas

====Just price====
Thomas Aquinas distinguished the [[Just price|just]], or natural, price of a good from that price which manipulates another party. He determines the just price from a number of things. First, the just price must be relative to the worth of the good. Thomas held that the price of a good measures its quality: "the quality of a thing that comes into human use is measured by the price given for it".<ref>{{Cite book |title=Summa Theologica |last=Aquinas |first=Thomas |publisher=English Dominican Fathers |year=1981 |location=New York |pages=II-II, Q77, A1}}</ref> The price of a good, measured by its worth, is determined by its usefulness to man. This worth is subjective because each good has a different level of usefulness to every man. The price should reflect the current value of a good according to its usefulness to man. "Gold and silver are costly not only on account of the usefulness of the vessels and other like things made from them, but also on account of the excellence and purity of their substance."<ref>{{Cite book |title=Summa Theologica |last=Aquinas |first=Thomas |publisher=English Dominican Fathers |year=1981 |location=New York |pages=II-II, Q77, A2}}</ref>