The primary aim of any literary history is to foster a deeper appreciation of the creative writing which it describes; to define the qualities of the works themselves must be its main concern. Roman literature, however, demands the reader's attention for a second reason, because more than any other national literature it has dictated the forms and modes of thought of subsequent European letters. For more than fifteen centuries after Virgil and Livy, Latin remained the learned language of Europe, constantly evoking the great auctores of the classical period. Then, side by side with the Latin writings of the High Middle Ages and the Renaissance, the vernacular literatures of the twelfth to the sixteenth centuries likewise boast their proud descent from the antique Romans, who continue to breathe inspiration into Western letters after the Renaissance. This epilogue concerns itself chiefly with the medieval period and the more important classical influences within it.

The ways in which the Latin classics impinged on the imaginative experience of later generations were shaped by a complex of political, economic and social factors but above all by the emergence of dominant Christian thinkers in the fourth-century West. These Christian leaders, emerging shortly after the establishment of Christianity as the favoured religion of the state, exploited their education in classical eloquence to proclaim the superiority of Christian beliefs over traditional Roman values. As Christians they inherited attitudes towards classical literature in which the denunciation of a Tertullian rang louder than the approval of a Lactantius; as educated Romans they found their modes of thought and powers of expression moulded by the authors they sought to reject.

The nature and history of insolubilia

Medieval literature on ‘insolubles’ began to appear by the early thirteenth century at the latest and continued to the end of the Middle Ages. Insolubles were primarily certain sorts of self-referential sentences, semantic paradoxes like the ‘liar paradox’ (‘What I am now saying is false’). But few authors tried to give a rigorous definition, so that other more or less unrelated kinds of paradoxes were also treated under this heading.

Three periods may be distinguished in the medieval insolubilia literature: (1) from the beginnings to ca. 1320; (2) the period of the most original work, from ca. 1320 to the time of the Black Death (1347–50); (3) after ca. 1350, a period of refinement and elaboration but, with a few exceptions, little that was new.

Resolutions in terms of cassation

Several approaches may be distinguished during the first period. One was called ‘cassation’ – i.e., nullification. On this theory, he who utters an insoluble ‘says nothing’. The earliest known text adopts this view, and by ca. 1225 it was said to be ‘according to the common judgement’. Nevertheless, it soon died out and seems not to have been revived until David Derodon in the seventeenth century. It is not clear how the theory is to be taken. In the middle thirteenth century a text attributed to William of Sherwood discussed several views that might be considered versions of cassation, including one theory that insolubles for semantic reasons fail to be sentences, so the he who utters them ‘says nothing’. This theory has modern parallels, e.g., in Fitch 1970.

The Aristotelian origins of the doctrine

The conception of potential and agent intellect came to Western medieval philosophy with the assimilation of Aristotle's theory of soul in his De anima. In this text, intellective cognition was understood as the reception of abstract concepts; therefore Aristotle conceived an intellective power capable of receiving which, in order to accomplish this function, had a purely potential nature. In several passages of the De anima, this power is called nous pathētikos (Lat. intellects possibilis). The process of cognition starts, however, with the data of sensitive cognition, which are particular and not universal. Therefore the reception of abstract concepts must be preceded by the abstraction of the universal content from sensible images. In order to explain this action, Aristotle conceived of an active power which his Greek commentators named nous poietikos (Lat. intellectus agens). Neither the exact functions of the two powers nor the relation between them was very clear in the De anima. In some portions of the text, the intellect was described as a part of the soul, which was defined by Aristotle as a substantial form of the body, but other sections considered the intellect as having a nature different from the soul-form of the body. This difference was especially stressed in the case of the active power, which was at various points described as being separate from the body and surviving death, or as inseparably joined to the body. These and other inconsistencies in Aristotle's text opened the way to different interpretations beginning with such Greek commentators as Themistius and Alexander of Aphrodisias, and carrying on through medieval Arabic ‘Aristotelian’ theories of the soul.

Natural philosophy, first philosophy, and moral philosophy

When the ‘new’ Aristotelian books of philosophy were incorporated into the curriculum of the medieval Faculty of Arts by 1252, they were simply added as ‘the three philosophies’ to an existing curriculum of the seven liberal arts, a course requiring up to eight years before one became a Regent Master. The ‘new logic’ (logica nova,) namely the two Analytics, Topics, and Elenchi, had merely expanded the old study of logic, which had even assimilated the logica modernorum without substantially changing the curriculum. But the addition of the hitherto proscribed (1210–ca. 1237) libri naturales and Metaphysics, together with the Nicomachean Ethics translated in full (1245–7) by Robert Grosseteste, expanded the curriculum substantially to include three new ‘sciences’: natural philosophy, first philosophy (or metaphysics), and moral philosophy. Thus during the second half of the thirteenth century was inaugurated what might be called the Faculty of Arts and Sciences.

The assimilation of the new learning

It was a period that saw an unprecedented assimilation of ‘the new learning’ not only in the Faculty of Arts, but more especially in the Faculty of Theology. However, the most notable assimilation and syntheses of the new learning both in philosophy and in theology were accomplished by theologians who had already passed through the university system and embarked on their own re-thinking of Christian truths ‘new and old’. This was particularly true of such leading scholars as Robert Grosseteste, Albert the Great, Thomas Aquinas, Roger Bacon, and later Thomas Bradwardine.

Sources of the medieval concept of natural law

The chief sources on which the scholastics drew for their knowledge of natural law were Cicero, the Digest, St Paul, the Fathers and, later, Aristotle.

St Paul observed in his Epistle to the Romans, 2.12–16, that even without knowledge of the Old Testament Law pagans have its substance written on their hearts. Conscience and reason lead men to do by nature what the Law commands. Natural law thus accords with the Decalogue. Lactantius recorded Cicero's definition of law: true law is right reason in agreement with nature, being found among all men, summoning them to duty and prohibiting wrongdoing. True law may not be abolished by Senate or People; it is not different in Rome or in Athens, now or in the future. Its originator and promulgator is God; disobedience to it constitutes a denial of the nature of man.

The Digest in its first chapter distinguished three types of law: ius civile or the law of the state, ius gentium or the law of nations, and ius naturale or the law of nature. The jurists cited defined the natural law variously. Ulpian described it as the common instinct of animals; the union of male and female, the procreation of offspring and their education have been taught to animals by nature. But Gaius defined the natural law as those human laws practised by all nations and dictated to all men by natural reason, and Paulus said that the natural law consists of what is equitable and good.

Philosophical and theological motivations for Aquinas' work

At least two distinct purposes may be discerned in Aquinas' various writings on human action. One is to complete and correct Aristotle's treatment of it in the Nicomachean Ethics, to which he of course pays close and respectful attention. A second springs from his primary commitment to theology. Reflecting on what is said in the Scriptures and the writings of the Fathers about such topics as the fall of Adam, sin, conversion, and the operation of grace, theologians produced a body of doctrine about various aspects of human acts. To Aquinas' mind, this teaching settles certain questions authoritatively: as when it declares that voluntary human acts are commanded by their agents freely, and not by necessity. In addition it introduces certain concepts into the theory of action, for example, those of enjoyment and consent. Aquinas undertakes to incorporate these contributions of theology, where sound, into a revised Aristotelian theory.

Aristotelian causal theories

Aristotelian theories of action are causal, and causal in a distinctive way. To do something, to perform an act, is to cause something. And causing something is always to be investigated in terms of a pair of fundamental concepts, dynamis and energeia, which appear in Thomas' Latin as potentia (potency) and actus (act). The power or capacity of an object to cause something – whether a change of state, or a persistence in a state – largely determines what that object is. Brute animals are distinguished by their possession of powers of sensation and bodily movement.

Origins of the medieval discussion: Peter Lombard

Medieval treatises on conscience were divided into two parts, one headed ‘synderesis’ and the other ‘conscientia’. ‘Synderesis’ is just a corrupted transliteration of ‘suneidēsis’ the Greek word for ‘conscience’, so the medieval distinction between synderesis and conscientia requires explanation. In the first instance, the explanation is historical. Conscience was not directly treated either by Plato or by Aristotle; the way in which it became a standard topic of later medieval philosophy was curious, almost an accident. Like many other topics regularly discussed by medieval philosophers, it came to their attention through a passage in Peter Lombard's Sentences and most of the medieval treatises on conscience are to be found in commentaries on that work.

Yet Peter Lombard does not actually discuss conscience at all: his question is how the will can be bad (2.39). As usual, he reports several answers, though, exceptionally, without pronouncing judgement upon them at the end. He notes, first, that some people distinguish two senses of ‘voluntas’, in one of which it is a power, in the other the exercise of that power (1.3). This distinction was probably inspired by a parallel Aristotelian distinction, between two senses of ‘know’, the first dispositional, but the second involving actually thinking about what one knows, as is sometimes necessary when using one's knowledge. Similarly, we each have a host of desires, but it is only at certain times that any one of them makes itself felt or that we pay attention to it, so that it is then actualised in the sense of being called to mind.

Schools and universities

Medieval philosophical literature is closely associated with medieval schools and universities as well as with the material and psychological conditions prevailing at these institutions. The economic prosperity of the eleventh and twelfth centuries, which is manifest in the rise of towns and the specialisation of labour, also had far-ranging repercussions in the world of learning. Learning was no longer confined to monasteries and monastic schools, but a new guild of professional intellectuals was created, which developed new intellectual aspirations. Such men were no longer satisfied with the traditional concept of Christian wisdom but wanted to pursue the whole domain of human learning, and they resolutely set out to recover and develop the intellectual heritage of antiquity.

Even in the very early Middle Ages, schools clustered around ecclesiastical centres, especially the chapters of episcopal sees, which throughout the Middle Ages provided the most important financial support for learning. Scholars shared the privileges of clergy although they were not required to take higher orders; in fact their clerical status was the best way of securing a certain amount of protection and independence against local authorities in surroundings which for the most part were hostile and brutal.

This description is especially appropriate for the situation in one of the centres of the twelfth-century intellectual expansion, the central part of France, between the Loire and the Rhine. Here schools flourished and decayed within short spans of time, often due to the presence or absence of one especially gifted teacher; Laon, Rheims, Melun, and Chartres are but a few examples of such schools.

Two notions of possibility

For Aristotle the term ‘possibility’ is homonymous (Pr. An. I, 3, 25a37–40): on some occasions the possible and the impossible are contradictories (e.g., De int. 12, 22a11–13; 13, 22a32–38), while on others possibility is incompatible not only with impossibility but also with necessity (e.g., An. pr. I, 13, 32a18–21). Whenever the distinction is relevant, I shall call possibility in the first sense ‘possibility proper’ and possibility in the second sense ‘contingency’.

In the Latin translation of De interpretatione by Marius Victorinus which was used by Boethius Aristotle's two terms for ‘possible’ were translated by the Latin terms ‘ possible’ and ‘ contingens’, which Boethius understood to be synonyms. This was the usual view in early medieval logic, and it can still be found in the squares of opposition for modalities presented by William of Sherwood and Peter of Spain in the middle of the thirteenth century. Already in the twelfth century, however, there were attempts to give separate meanings to the two words. For instance, John of Salisbury criticised those who used the terms as synonyms; according to usage in his time a mere absence of impossibility did not warrant calling something contingent. Even in those works in which the terms are used as synonyms there often is a remark referring to a related distinction, according to which ‘contingens’ is opposed to ‘necessarium’ in the sense that some possible sentences are necessary and others contingent. This became the dominant use of the words in later medieval logic.