Medieval economic views can be reconstructed only indirectly, through the works of theologians, moralists, lawyers, and philosophers for whom such issues did not constitute a field that deserved to be considered separately.
Even texts that are directly related to specific economic problems, such as money lending, only make sense as part of a more general perspective. In general, economic views are restricted to certain paragraphs in the Summa, the commentaries on Aristotle’s works on ethics or politics, or comments on contracts in canon or civil law.
These economic ideas therefore appear as a kind of projection from theological, philosophical, moral, political or legal concepts to the economic aspects of social life, especially as they concern human behaviour.In this respect, the economic reasoning of the Middle Ages could not be considered an economic theory in the modern sense. Characterized by a comparative approach, it consists of two procedures. First, within the framework of general conceptions of society, a norm for economic activity is formed. Secondly, economic behaviour and, further, economic intentions, are analysed and assessed for whether they conform to that norm. Understanding this duality is particularly important since it permits an explanation of certain apparent contradictions between the various judgements of the schoolmen. Moreover, it helps prevent the erroneous though widespread tendency to read medieval economic analysis through exclusively normative glasses: whatever the norm is (a just price, for instance), the existence of a possible gap between this norm and actual transactions requires an explanation to support the judgement of the moralist, whether priest or judge. The elements of medieval economic analysis lie in this explanation.
This does not mean that apparently familiar economic categories (price, interest, exchange, money, and competition) can be understood as they would be today. What makes them unfamiliar is their dependence both on specific conceptions of society, and on the specific goals of the age.
Three main sources formed the intellectual basis of the economic thought of the Middle Ages.
The first comprises the traditional teaching of the church, drawing on the Gospels and on the wide corpus of patristic literature. The second source is provided by the Latin translations of Aristotle, mainly his Nicomachean Ethics and his Politics, which spread across the western world during the thirteenth century. Usually these translations were indirect, since Aristotle’s moral and philosophical works were known from previous translations by Muslim and Jewish commentators. The third source is Roman law, rediscovered through the works of glossators during the second half of the eleventh century. These three sources sustained an ambitious project, initiated by Albert the Great and his follower Thomas Aquinas, as a reaction against the spread of the doctrine of the double truth - truth of reason and truth of faith - attributed to Averroes, and taught in Paris by Siger of Brabant. The purpose of this project was the conciliation of reason and faith by showing that faith is founded on reason. Aristotle’s philosophy here played a crucial role, in that it allowed the rationalization of theological doctrines.On first sight, this seems far from economic matters. Nonetheless, philosophical positions such as Albert’s and Thomas’s brought with them a conception of society which is worth mentioning from the viewpoint of such matters. From Aristotle they borrowed a teleological and organicist conception of society. The first feature gives rise to a hierarchy of natures, which goes from inanimate things up to vegetables, animals, men, and, at the top of the pyramid, God. Since the end of each level in this hierarchy is to be found in the higher level, men appear on this earth not only as God’s creatures, but as agents of the Creation, endowed with reason. The second feature draws on Aristotle’s political philosophy, for instance, on Politics, book 1, where he argued that man is a “political animal”, since his ends and capacities can be satisfied only through his function within the political organization of the City, just like any particular organ within the organism of which it is a part.
This does not only mean that, as Thomas argued, again following “the Philosopher” (Aristotle), “the whole must of necessity be prior to the part” (Thomas Aquinas, Summa Theologiae, IIa-IIae, q.58, a.5, resp.), but that our place in society as a part of it conforms to an external hierarchy of ends which, as beings endowed with reason, it is our task to discover.However, society was far from being considered only from the point of view of Thomism. In 1277 - that is, three years after Thomas Aquinas’s death - Averroist theses were condemned by the Bishop of Paris. It was clear to everyone that, behind Averroes, this condemnation was aimed at the teachings of Aquinas, whose eminent position was not all that firmly established outside the Dominican order. As early as the beginning of the fourteenth century, there was a gradually increasing influence of alternative trends of thought coming mainly from the Franciscan order, through figures such as John Duns Scotus and William of Ockham who set out what is now known respectively as “Scotism” and “nominalism”. From a philosophical point of view, both might be seen as ways of importing other influences (Plato and, concerning Islamic philosophy, Avicenna), of reframing the influence of Aristotle, or even of moving away from it. However, it was also a way to provide more individualistic foundations to the conception of society, either through a contractualist approach (Scotism), or through an approach which dismissed the possibility that a category like “men” in general, independently from the particularities of each single individual, might constitute the basis of society (nominalism).
These considerations are far from strictly academic, since they explain some of the variants of the analysis of economic categories among the schoolmen.