This article does not treat in detail the many complexities of modern price justice, but attempts only to state generally accepted moral principles governing the just price. These principles are meant to apply to staple commodities bought and sold in the open market; they do not necessarily apply to rare articles or occasional private transactions.
Notion of a Just Price . The price of a thing is its value in terms of money. Value, in this context, is the capacity of goods to satisfy human wants. Money is the medium of exchange; it serves as a general standard of value for all goods. Fundamentally, then, the just price is the true money value of the commodity, a price that can buy other commodities having a capacity for satisfying human wants equal to that of the commodity sold. The whole concept of commutative justice is based on the idea of equality. Modern commerce, though very complex, is rooted in the same idea of equality. It aims at allowing a person to obtain the equal of what he gives. This idea of equality is not opposed to the idea of profit; a person is entitled to the fruit of his industry or ingenuity. One may profit without violating justice, but justice sets limits on the methods by which profit may legitimately be gained.
Determination of the Just Price. The problem facing the moralist is this: How can the equal capacity of commodities for satisfying human wants be calculated? Extreme answers to this question must be rejected. One extreme view holds that each commodity has a fixed money value that van be exactly determined at any given time. This view must be rejected, since it is impossible to determine human needs and desires with precision; these needs vary widely from person to person, and from time to time, and depend on too many purely psychological factors, such as taste and fashion. Another extreme view is that all value so depends on the whims of individual buyers that any price they are willing to pay is just. This position must be rejected because it is immoral; it would thwart the very idea of money as a medium of exchange, of trade as a function of society, and of commutative justice as a moral virtue.
In opposition to such views, the traditional, natural law theory maintains that the just price should be determined not by the usefulness of a commodity to this or that individual, but to men generally. The price should represent the judgment of the general buying public on the value of a particular commodity. This judgment is expressed in the open market, where buyers and sellers freely compete with one another and establish in the process a true equality between the capacities of different commodities to satisfy human wants. The competitive price is, then, the natural (or common) price that will drive out all other prices. Wherever there is pure competition, this competitive price will be the just price. This competitive or common price is not static. Neither is it exactly determinable, but may range between a highest and a lowest limit. Within this range any price could be considered just.
Legal Price . At times, in order to protect the interests of both buyers and sellers and to offset attempts to raise or lower prices artificially, public authority may consider it necessary to establish a legal price. In this case, value is set at a particular level and an adequate price for a commodity or service is fixed by law. Moralists agree that this legal price, where established, is the just price. However, deviations is considerably better (or worse) than the standard item, or if the established price is no longer observed by most people with the tacit consent of the public authority.
In pricing things for which there is no established market to furnish a common estimate of value, or no legal price, justice depends on the judgment of appraisers experienced in such transactions. This is sometimes called the conventional price because it is formed by compact or agreement. Moralists hold that a just price for things whose value is uncertain is reached when both parties to the bargain freely and honestly consent to it. There is agreement among Catholic moralists that: (1) It is against justice, in ordinary circumstances, to demand more than the legal price permits; (2) To sell above the highest just price or to buy below the lowest is a violation of justice.
Bibliography: j. messner, Social Ethics: Natural Law in the Modern World, tr. j. j. doherty (St. Louis 1957). v. a. demant, ed., The Just Price: The Medieval Doctrine and Its Possible Equivalent Today (London 1930). p. boven, Le Prix normal (Paris 1924). o. von nell–breuning, Lexicon für Theologie und Kirsche, ed. j. hofer and k. rahner (2d, new ed. Freiburg 1957–65) 8:719–721. a. michel, Dictionnaire de théologie catholique, ed. a. vacant et al., 15 v. (Paris 1903–50; Tables générales 1951) 15.2:2625–31.
"Just Price." New Catholic Encyclopedia. . Encyclopedia.com. (December 15, 2018). https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/just-price
"Just Price." New Catholic Encyclopedia. . Retrieved December 15, 2018 from Encyclopedia.com: https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/just-price