Aristotle

Aristotle's Politics (c.a. 350 BC) was mainly concerned to analyse different forms of a state (monarchy, aristocracy, constitutional government, tyranny, oligarchy, democracy) as a critique of Plato's advocacy of a ruling class of "philosopher-kings". In particular for economists, Plato had drawn a blueprint of society on the basis of common ownership of resources. Aristotle viewed this model as an oligarchical anathema.

In Politics Book I, Aristotle discusses the general nature of households and market exchanges. For him there is a certain "art of acquisition" or "wealth-getting". Money itself has the sole purpose of being a medium of exchange, which means on its own "it is worthless... not useful as a means to any of the necessities of life".^[15] Nevertheless, points out Aristotle, because the "instrument" of money is the same many people are obsessed with the simple accumulation of money. "Wealth-getting" for one's household is "necessary and honourable", while exchange on the retail trade for simple accumulation is "justly censured, for it is dishonourable".^[16] Aristotle disapproved highly of usury and also cast scorn on making money through monopoly.^[17]

Middle Ages

Thomas Aquinas (1225-1274) was an Italian theologian and writer on economic issues. He taught in both Cologne and Paris, and was part of a group of Catholic scholars known as the Schoolmen, who moved their enquiries beyond theology to philosophical and scientific debates. In the treatise Summa Theologica Aquinas dealt with the concept of a just price, which he considered necessary for the reproduction of the social order. Bearing many similarities with the modern concept of long run equilibrium a just price was supposed to be one just sufficient to cover the costs of production, including the maintenance of a worker and his family. He argued it was immoral for sellers to raise their prices simply because buyers were in pressing need for a product.

Aquinas discusses a number of topics in the format of questions and replies, substantial tracts dealing with Aristotle's theory. Questions 77 and 78 concern economic issues, mainly relate to what a just price is, and to the fairness of a seller dispensing faulty goods. Aquinas argued against any form of cheating and recommended compensation always be paid in lieu of good service. Whilst human laws might not impose sanctions for unfair dealing, divine law did, in his opinion. One of Aquinas' main critics^[18] was Duns Scotus (1265-1308) in his work Sententiae (1295). Originally from Duns Scotland, he taught in Oxford, Cologne and Paris. Scotus thought it possible to be more precise than Aquinas in calculating a just price, emphasising the costs of labour and expenses - though he recognised that the latter might be inflated by exaggeration, because buyer and seller usually have different ideas of what a just price comprises. If people did not benefit from a transaction, in Scotus' view, they would not trade. Scotus defended merchants as performing a necessary and useful social role, transporting goods and making them available to the public.