Medieval philosophy is the philosophy in the era now known as medieval or the Middle Ages, the period roughly extending from the fall of the Western Roman Empire in the fifth century AD to the Renaissance in the sixteenth century. Medieval philosophy, understood as a project of independent philosophical inquiry, began in Baghdad, in the middle of the eighth century, and in France, in the itinerant court of Charlemagne, in the last quarter of the eighth century.1 It is defined partly by the process of rediscovering the ancient culture developed in Greece and Rome in the classical period, and partly by the need to address theological problems and to integrate sacred doctrine with secular learning.
The history of medieval philosophy is traditionally divided into two main periods: the period in the Latin West following the Early Middle Ages until the twelfth century, when the works of Aristotle and Plato were preserved and cultivated and the 'golden age' of the twelfth, thirteenth and fourteenth centuries in the Latin West, which witnessed the culmination of the recovery of ancient philosophy, along with a reception of its Arabic commentators, and significant developments in the field of Philosophy of religion, Logic and Metaphysics.
The medieval era was disparagingly treated by the Renaissance humanists, who saw it as a barbaric 'middle' period between the classical age of Greek and Roman culture, and the 'rebirth' or renaissance of classical culture. Modern historians consider the medieval era to be one of philosophical development, although one heavily influenced by Christian theology. One of the most notable thinkers of the era, Thomas Aquinas, never considered himself a philosopher, and criticized philosophers for always "falling short of the true and proper wisdom to be found in Christian revelation".2
The problems discussed throughout this period are the relation of faith to reason, the existence and simplicity of God, the purpose of theology and metaphysics, and the problems of knowledge, of universals, and of individuation.3
Medieval philosophy is characteristically theological: With the possible exceptions of Avicenna and Averroes, medieval thinkers did not consider themselves philosophers at all. Their concerns are theological: For them, the philosophers were the ancient pagan writers such as Plato and Aristotle.4 However, the theological works of medieval writers use the ideas and logical techniques of the ancient philosophers to address difficult theological questions, and points of doctrine. Thomas Aquinas, following Peter Damian, argued that philosophy is the handmaiden of theology (ancilla theologiae).5
The three principles that underlie all their work are the use of logic, dialectic, and analysis to discover the truth, known as ratio, respect for the insights of ancient philosophers, in particular Aristotle, and deference to their authority (auctoritas), and the obligation to co-ordinate the insights of philosophy with theological teaching and revelation (concordia).6
One of the most heavily debated topics of the period was that of faith versus reason. Avicenna and Averroes both leaned more on the side of reason. Augustine stated that he would never allow his philosophical investigations to go beyond the authority of God.7 Anselm attempted to defend against what he saw as partly an assault on faith, with an approach allowing for both faith and reason.8 The Augustinian solution to the faith/reason problem is to (1) believe, and then (2) seek to understand.
The boundaries of the early medieval period are a matter of controversy.9 It is generally agreed that it begins with Augustine (354 – 430) who strictly belongs to the classical period, and ends with the lasting revival of learning in the late eleventh century, at the beginning of the high medieval period
After the collapse of the Roman empire, Western Europe lapsed into the so-called Dark Ages. Monasteries were among the limited number of focal points of formal academic learning, which might be presumed to be a result of a rule of St Benedict's in 525, which required monks to read the Bible daily, and his suggestion that at the beginning of Lent, a book be given to each monk. In later periods, monks were used for training administrators and churchmen.10
Early Christian thought, in particular in the patristic period, tends to be intuitional and mystical, and is less reliant on reason and logical argument. It also places more emphasis on the sometimes-mystical doctrines of Plato, and less upon the systematic thinking of Aristotle.11 Much of the work of Aristotle was unknown in the West in this period. Scholars relied on translations by Boethius into Latin of Aristotle's Categories, the logical work On Interpretation, and his Latin translation of Porphyry's Isagoge, a commentary on Aristotle's Categories.12
Two Roman philosophers had a great influence on the development of medieval philosophy: Augustine and Boethius. Augustine is regarded as the greatest of the Church Fathers. He is primarily a theologian and a devotional writer, but much of his writing is philosophical. His themes are truth, God, the human soul, the meaning of history, the state, sin, and salvation. For over a thousand years, there was hardly a Latin work of theology or philosophy that did not quote his writing, or invoke his authority. Some of his writing had an influence on the development of early modern philosophy, such as that of Descartes.13 Anicius Manlius Severinus Boethius (480– c.525) was a Christian philosopher born in Rome to an ancient and influential family. He became consul in 510 in the kingdom of the Ostrogoths. His influence on the early medieval period was also marked (so much so that it is sometimes called the Boethian period).14 He intended to translate all the works of Aristotle and Plato from the original Greek into Latin, and translated many of Aristotle’s logical works, such as On Interpretation, and the Categories. He wrote commentaries on these works, and on the Isagoge by Porphyry (a commentary on the Categories). This introduced the problem of universals to the medieval world.15
The first significant renewal of learning in the West came when Charlemagne, advised by Peter of Pisa and Alcuin of York, attracted the scholars of England and Ireland, and by imperial decree in 787 AD established schools in every abbey in his empire. These schools, from which the name Scholasticism is derived, became centres of medieval learning.
Johannes Scotus Eriugena (c. 815 - 877), successor of Alcuin of York as head of the Palace School, was an Irish theologian and Neoplatonic philosopher. He is notable for having translated and made commentaries upon the work of Pseudo-Dionysius, initially thought to be from the apostolic age. Around this period several doctrinal controversies emerged, such as the question of whether God had predestined some for salvation and some for damnation. Eriugena was called in to settle this dispute. At the same time, Paschasius Radbertus raised an important question about the real presence of Christ at the Eucharist. Is the host the same as Christ's historical body? How can it be present at many places and many times? Radbertus argued that Christ's real body is present, veiled by the appearance of bread and wine, and is present at all places and all times, by means of God's incomprehensible power.16
This period also witnessed a revival of scholarship. At Fleury, Theodulphus, bishop of Orléans, established a school for young noblemen recommended there by Charlemagne. By the mid-ninth century, its library was one of the most comprehensive ever assembled in the West, and scholars such as Lupus of Ferrières (d. 862) traveled there to consult its texts. Later, under St. Abbo of Fleury (abbot 988-1004), head of the reformed abbey school, Fleury enjoyed a second golden age.17
Remigius of Auxerre, at the beginning of the tenth century, produced glosses or commentaries on the classical texts of Donatus, Priscian, Boethius, and Martianus Capella. The Carolingian period was followed by a small dark age that was followed by a lasting revival of learning in the eleventh century, which owed much to the rediscovery of Greek thought from Arabic translations and Muslim contributions such as Avicenna's On the soul.18
The period from the middle of the eleventh century to the middle of the fourteenth century is known as the 'High medieval' or 'scholastic' period. It is generally agreed to begin with Saint Anselm of Canterbury (1033–1109) an Italian philosopher, theologian, and church official who is famous as the originator of the ontological argument for the existence of God.
The 13th and early 14th centuries are generally regarded as the high period of scholasticism. The early 13th century witnessed the culmination of the recovery of Greek philosophy. Schools of translation grew up in Italy and Sicily, and eventually in the rest of Europe. Scholars such as Adelard of Bath travelled to Sicily and the Arab world, translating works on astronomy and mathematics, including the first complete translation of Euclid’s Elements.19 Powerful Norman kings gathered men of knowledge from Italy and other areas into their courts as a sign of their prestige.20 William of Moerbeke's translations and editions of Greek philosophical texts in the middle half of the thirteenth century helped in forming a clearer picture of Greek philosophy, and in particular of Aristotle, than was given by the Arabic versions they had previously relied on, which had distorted or obscured the relation between Platonic and Aristotelian systems of philosophy.21 His work formed the basis of the major commentaries that followed.
The universities developed in the large cities of Europe during this period, and rival clerical orders within the Church began to battle for political and intellectual control over these centers of educational life. The two main orders founded in this period were the Franciscans and the Dominicans. The Franciscans were founded by Francis of Assisi in 1209. Their leader in the middle of the century was Bonaventure, a traditionalist who defended the theology of Augustine and the philosophy of Plato, incorporating only a little of Aristotle in with the more neoplatonist elements.22 Following Anselm, Bonaventure supposed that reason can discover truth only when philosophy is illuminated by religious faith. Other important Franciscan writers were Duns Scotus, Peter Auriol, and William of Ockham.
By contrast, the Dominican order, founded by St Dominic in 1215 placed more emphasis on the use of reason and made extensive use of the new Aristotelian sources derived from the East, and Moorish Spain. The great representatives of Dominican thinking in this period were Albertus Magnus and (especially) Thomas Aquinas, whose artful synthesis of Greek rationalism and Christian doctrine eventually came to define Catholic philosophy. Aquinas placed more emphasis on reason and argumentation, and was one of the first to use the new translation of Aristotle's metaphysical and epistemological writing. This was a significant departure from the Neoplatonic and Augustinian thinking that had dominated much of early Scholasticism. Aquinas showed how it was possible to incorporate much of the philosophy of Aristotle without falling into the "errors" of the Commentator Averroes.
The start of the 20th century historian and philosopher Martin Grabmann was the first scholar to work out the outlines of the ongoing development of thought in scholasticism and to see in Thomas Aquinas a response and development of thought rather than a single, coherently emerged and organic whole. Although Grabmann's works in German are numerous, only Thomas Aquinas (1928) is available in English. However, Grabmann's thought was instrumental in the whole modern understanding of scholasticism and the pivotal role of Aquinas.
Medieval philosophers wanted authority to be absolute, but faced a problem that the authorities might not be in agreement with more recently gained knowledge, or their own point of view. A formal characteristic found in medieval philosophical texts is the citation of authoritative texts, e.g., the Bible or Aristotle. A way to forge agreements with and among authorities was a reinterpretation of them. This was a way to bring an author's view into conversation, and to be in agreement with contemporary discussions. For example, Maimonides argues that, just as a boy reared on an island without women would have difficulty imagining how children might be conceived and born, Aristotle might have had an experience too limited to allow him to develop any other accounts of the origin of things. In addition to reinterpretation, medieval interpreters might also take a given citation out of context. For example, Aquinas cites Augustine out of context to claim that theology is a “science” analogous to the Aristotelian science of “Posterior Analytics”, by failing to note that Augustine uses the term “science” in a much older and less technical way. Alan of Lille supports the empiricist Pauline claim that the “invisible things of God are known through the visible things that are made”, but with a different context, whereby the kind of knowledge in question is the “knowledge” of faith, not of the world. Likewise, Aquinas cites and supports the categorization of sin in terms of Gregory the Great's scheme of the seven deadly sins, but he subordinates Gregory's classification to his own way of organizing notions of sin. This change of contexts to make a point is not necessarily done in bad faith; their strategies for harmonizing authorities discordant with each other and with their own views may be part of a hermeneutic whose basic assumption is that these authorities are all seeking and attempting to express part of a single Truth, so it is not a distortion of an authoritative source to put its views in a new context when new concepts and knowledge demands this be done. Silano points out that many of the tensions and even outright contradictions between authoritative sources would have disappeared had the compilers, commentators, and masters determining a question placed those authoritative claims in their historical/cultural context rather than simply set them against each other, and that they might not have done so because this would deprive these sources of their normative status, making it contingent as a judicial decision, interpreted in terms of its historical/cultural context, is no longer binding. Silano wanted the task of the 12th and 13th centuries in the Latin West to be the establishment of absolute authorities, which would bound all discussion and dissention, rather than knocking them down through arguments of relativism.2324
All the main branches of philosophy today were a part of Medieval philosophy. Medieval philosophy also included most of the areas originally established by the pagan philosophers of antiquity, in particular Aristotle. However, the discipline now called Philosophy of religion was, it is presumed, a unique development of the Medieval era, and many of the problems that define the subject first took shape in the Middle Ages, in forms that are still recognisable today.
Medieval philosophy is characteristically theological. Subjects discussed or developed in this period include:
- The problem of the compatibility of the divine attributes: How are the attributes traditionally ascribed to the Supreme Being, such as unlimited power, knowledge of all things, infinite goodness, existence outside time, immateriality, and so on, logically consistent with one another?
- The problem of evil: The classical philosophers had speculated on the nature of evil, but the problem of how an all-powerful, all-knowing, kind God could create a system of things in which evil exists first arose in the medieval period.
- The problem of free will: A similar problem was to explain how 'divine foreknowledge' - God's knowledge of what will happen in the future - is compatible with our belief in our own free will.
After the 'rediscovery' of Aristotle's Metaphysics in the mid-twelfth century, many scholastics wrote commentaries on this work (in particular Aquinas and Scotus). The problem of universals was one of the main problems engaged during that period. Other subjects included:
- Hylomorphism - development of the Aristotelian doctrine that individual things are a compound of material and form (the statue is a compound of granite, and the form sculpted into it)
- Existence - being qua being
- Causality - Discussion of causality consisted mostly of commentaries on Aristotle, mainly the Physics, On the Heavens, On Generation and Corruption. The approach to this subject area was uniquely medieval, the rational investigation of the universe being viewed as a way of approaching God. Duns Scotus' proof of the existence of God is based on the notion of causality.
- Individuation. The problem of individuation is to explain how we individuate or numerically distinguish the members of any kind for which it is given. The problem arose when it was required to explain how individual angels of the same species differ from one another. Angels are immaterial, and their numerical difference cannot be explained by the different matter they are made of. The main contributors to this discussion were Aquinas and Scotus.
In natural philosophy and the philosophy of science, medieval philosophers were mainly influenced by Aristotle. However, from the fourteenth century onward, the increasing use of mathematical reasoning in natural philosophy prepared the way for the rise of science in the early modern period. The more mathematical reasoning techniques of William Heytesbury and William of Ockham are indicative of this trend. Other contributors to natural philosophy are Albert of Saxony, John Buridan, and Nicholas of Autrecourt. See also the article on the Continuity thesis, the hypothesis that there was no radical discontinuity between the intellectual development of the Middle Ages and the developments in the Renaissance and early modern period.
The great historian of logic I. M. Bochenski25 regarded the Middle Ages as one of the three great periods in the history of logic. From the time of Abelard until the middle of the fourteenth century, scholastic writers refined and developed Aristotelian logic to a remarkable degree. In the earlier period, writers such as Peter Abelard wrote commentaries on the works of the Old logic (Aristotle's Categories, On interpretation, and the Isagoge of Porphyry). Later, new departments of logical enquiry arose, and new logical and semantic notions were developed. For logical developments in the Middle Ages, see the articles on Insolubilia, Medieval theories of modality, Obligations, Properties of terms, Medieval theories of singular terms, Syllogism, and Sophismata. Other great contributors to medieval logic include Albert of Saxony, John Buridan, John Wyclif, Paul of Venice, Peter of Spain, Richard Kilvington, Walter Burley, William Heytesbury, and William of Ockham.
Medieval philosophy of mind is based on Aristotle's De Anima, another work discovered in the Latin West in the twelfth century. It was regarded as a branch of the philosophy of nature. Some of the topics discussed in this area include:
- Divine illumination - The doctrine of Divine illumination was an alternative to naturalism. It holds that humans need a special assistance from God in their ordinary thinking. The doctrine is most closely associated with Augustine and his scholastic followers. It reappeared in a different form in the early modern era.
- theories of demonstration
- mental representation - The idea that mental states have 'intentionality'; i.e., despite being a state of the mind, they are able to represent things outside the mind is intrinsic to the modern philosophy of mind. It has its origins in medieval philosophy. (The word 'intentionality' was revived by Franz Brentano, who was intending to reflect medieval usage26). Ockham is well known for his theory that language signifies mental states primarily by convention, real things secondarily, whereas the corresponding mental states signify real things of themselves and necessarily.27
- Christian philosophy
- Jewish philosophy
- Early Muslim philosophy
- Scholastic philosophy
- Renaissance of the 12th century
- Supposition Theory
- Pasnau, Robert (2010). "Introduction". The Cambridge History of Medieval Philosophy. Cambridge, UK: Cambridge University Press. p. 1. ISBN 978-0-521-76216-8.
- Davies, Brian (2004). Aquinas. Continuum International Publishing Group. p. 14.
- Gracia & Noone p1
- Gracia & Noone p 1)
- Gracia & Noone p.35
- Gracia & Noone pp.3-5
- Kretzmann & Stump p 27
- Gracia & Noone p 1
- Gracia & Noone p.45
- Russell, Book II, Part i, c. 6
- Russell p.353
- Hyman & Walsh p. 15
- McGavin p. 53
- Hyman & Walsh pp.114-117
- Gracia & Noone pp.397-406
- Schulman, p.1
- Jonathan Lyons (2007). The House of Wisdom. Bloomsbury.
- Clagett (1982), p. 356.
- Lindberg (1978), p. 70-72.
- Hyman & Walsh, 'Bonaventura', p.454
- History of Western Philosophy, Bertrand Russell
- Literary Forms of Medieval Philosophy, Stanford Encyclopedia of Philosophy, 
- Bochenski 1961, pp. 10-18
- Brentano, tr. Chisholm p.50
- That is, our idea of a rabbit necessarily represents a rabbit. A mental state 'is a true similitude of the external thing, on account of which it represents (repraesentat) the external thing itself, and stands for it from its nature, just as an utterance denotes things by institution'.
- The London Philosophy Study Guide offers many suggestions on what to read, depending on the student's familiarity with the subject: Medieval Philosophy
- Brentano, "The Distinction between Mental and Physical Phenomena", translated by D.B. Terrell, in Psychology from an Empirical Standpoint, 1874.
- Gallatin, H.K., Medieval Intellectual Life and Christianity
- Gracia, J.G. and Noone, T.B., A Companion to Philosophy in the Middle Ages, London 2003
- Hyman, J. and Walsh, J.J., Philosophy in the Middle Ages, Indianapolis 1973
- Kretzmann, N. and Stump, E., The Cambridge Companion to Augustine , Cambridge 2000.
- McGavin, J., Chaucer and Dissimilarity: Literary Comparisons in Chaucer.
- Maurer, Armand A. . Medieval Philosophy. 2nd ed. Toronto: Pontifical Institute of Mediaeval Studies.
- Russell, B., History of Western Philosophy, Routledge 1996 (originally published 1946)
- Schoedinger, Andrew B., ed. . Readings in Medieval Philosophy. New York: Oxford University Press.
- Jana K. Schulman The Rise of the Medieval World, 500-1300, Greenwood Publishing Group, 2002
- Medieval philosophy at PhilPapers
- Medieval philosophy at the Indiana Philosophy Ontology Project
- Medieval philosophy entry in the Stanford Encyclopedia of Philosophy
- Medieval philosophy entry in the Internet Encyclopedia of Philosophy
- Medieval Philosophy Electronic Resources
- Article Philosophy at The Catholic Encyclopedia
- Some medieval Jewish philosophers
- Medieval Natural Philosophy and the Church by James Hannam
- The Fathers, the Scholastics, and Ourselves by von Balthasar
- Stanford Encyclopedia of Philosophy:
- Medieval Philosophy and Theology journal
- (German) ALCUIN - Regensburger Infothek der Scholastik - Huge database with information on biography, text chronology, editions.