Abstract

Realism is a philosophical position that attributes extramental existence to certain kinds of entities, for example, universals, categories, relations, or propositions.

In philosophical language, the word realism is polyse-mous. One can be a realist, as opposed to an idealist, if one defends the view that material objects exist externally to us and independently of our sense experience; one can be a direct realist in the theory of perception if one holds that perception is a direct awareness of external objects, a moral realist if one believes that there are objective moral values, a scientific realist if one holds that scientific knowledge is about theory-independent phenomena and that such knowledge is possible even about nonobservable entities, a modal realist if one believes that possible worlds are as real as the actual world. In the history of medieval philosophy, the term realism is used first and foremost in the field of ontology. In this context, it indicates the fact that one attributes - in ways that vary greatly from case to case - extramental existence to certain kinds of entities. In consequence, a philosopher cannot be said to be a realist in any absolute or general fashion, but only in reference to universals, categories, relations, propositions, etc. A realist about Aristotelian categories, such as Duns Scotus for example, holds that the extramental world is divided into ten kinds or categories among which none can be reduced to another. A realist about relations holds that something more than the terms of the relation corresponds in extramental reality to our relational concepts. A realist about propositions, such as Walter Burley, holds that propositions exist in the world. However, realism about universals is the position that concentrated the most defenders, and also the most vocal critics. Realism about universals holds that universals - first and foremost the genera and species of the category of substance, such as animal, hedgehog, squirrel, or man - are things outside the mind. The question can be formulated in the following terms: is universality a mode of being or is it only a property of language? The realist holds that it is a mode of being; however, this is about the only thesis we can attribute to all realists, as there are a number of different realist theories that cannot be reduced to each other.

Let us begin by distinguishing the two main families of realist theories, Platonic realism and Aristotelian realism. The difference between theses theories is that Aristotelian realism defends the existence of universals in individuals, whereas Platonic realism grants them a mode of existence as separate from individuals.

This distinction of different types of realism draws on an older distinction, which dates back to middle Platonism, between two types of entities, in Greek idea (idea) and eidos (form). As noted by HB Gottschalk (1987): ‘‘from the early first century AD, it seems, Platonists distinguished the Platonic Form, ‘eternal pattern of natural objects’ from a Form immanent in particulars. The second comes straight from Aristotle and was designated by the term eidos, which had been used both by Plato and Aristotle, while the purely Platonic word idea was reserved for the first’’ (36.2:1144-1145). This distinction was refined by Neoplatonic authors in the so-called theory of the three states of the universal. This theory is a doctrinal product of the Neoplatonic exegesis of Aristotle’s Categories and Porphyry’s Isagoge and was inspired by the Neoplatonic project of seeking harmony between the philosophies of Plato and Aristotle. This theory is present in Ammonius (In Porphyrii Isagogen, 41:10-20), Elias (In Porphyrii Isagogen, 49:20-25), and David (In Porphyrii Isagogen, 120:8-14); it is also found in Simplicius (In Aristotelis Categorias, 82:35, 83:22). It distinguishes: (1) Universals that are before the multiple (pro tonpolion) - these are the ideal models or paradigms, which subsist in the Demiurge’s intellect; (2) Universals in the multitude (en tois pollois): the participated forms, which are inseparable from matter and immanent to particulars; (3) Universals that are after the multiple (epi toispollois): concepts, which are abstracted from immanent forms. This theory was transmitted to the Latin world through the intermediary of the translations of Avicenna’s Logic, Eustratios of Nicaea’s commentary to the Nicomachean Ethics, and through Simplicius’ commentary to the Categories. The Latin version of this theory that distinguishes between ante rem, in re, and post rem universals was soon to become a commonplace of scholastic thought on univer-sals. This theory also involved speaking of the theological universal, the metaphysical universal (whose characteristic is esse in multis), and the logical universal (whose characteristic is dici de multis). The nature of the ante rem universal may be considered in a strong and in a weaker version: in the strong version, ‘‘ante rem universal’’ refers to a real entity that is independent from both the human and divine minds, a pure Platonic form; in the weaker version - of which a specifically Christian form was widespread - ‘ante rem universal’’ refers to a divine idea (all these ideas put together are supposed to constitute the totality of God’s knowledge). This theory allows us to identify precisely which entities are those whose ontological status is discussed; more fundamentally, the relative importance given to one type of entity with respect to others provides three types of ontology. Before characterizing them, let us note that these types of universals are not mutually exclusive - philosophers are frequently found to defend several of them in parallel. Note also that two types of universals are accepted as really existing by almost all medieval philosophers: the ante rem universals in their weak version and the post rem universals. The idea of divine ideas was naturally linked to the Christian belief of the philosophers in question and was not questioned, even by strongly antirealist authors such as Peter Abelard. However, the emphasis put on these moderate ante rem universals indicates the importance which a philosopher gives to exemplarism in his philosophy and shows the level of Platonism of his thought. Similarly, post rem universals were universally accepted. No one thought of doing without concepts. The mode in which we grasp them - theory of abstraction versus illumination - may, indeed, be debated, but not their existence.

So we have three possible combinations: (1) Platonic ontology: defense of strong ante rem universals (this form is hardly found at all until the end of the Middle Ages). (2) Aristotelian realist ontology: rejection of strong ante rem universals, defense of in re universals. This theory is frequently encountered: it reflects Aristotle’s frame of mind, rejects separated universals, and states their existence as being only in individuals. (3) Aristotelian particularist or nominalist ontology: everything that exists is particular; both strong ante rem universals and in re universals are rejected. Universality is a property of terms only. This illustrates the fact that the main debate that took place in the framework of Aristotelianism was that of accepting or rejecting in re universals. Authorities that can be called upon in defense of the first solution include Augustine and Priscian; upholders of both (2) and (3) can call upon passages from Aristotle’s texts.

A passage from Priscian’s Institutiones grammaticae (XVII, 44; GL3, 135: 1-10) in which he speaks of the ‘‘generic and specific forms of things, which exist in an intelligible way in the divine mind before they come forth in bodies’’ played an important role in establishing this theory, just as did Augustine’s question De ideis (De diversis quaestionibus 46), which transmitted the theory of Platonic universals as divine ideas. Augustine says that these ideas are in God’s mind (in ipsa mente Creatoris) and nowhere else, thus confirming the Middle - and Neoplato-nist understanding of ideas as the Demiurge’s thoughts. Conversely, the rediscovery of Aristotle’s Metaphysics played against strong ante rem universals. Aristotle’s criticism of Platonic ideas clearly provoked scholastic mistrust of separate universals. The Organon, through three fundamental texts - Chap. 5 of the Categories, Chap. 7 of the Peri hermeneias, and a passage from the Posterior Analytics - provides most of the arguments in favor of in re universals. Chapter 5 ofthe Categories is central on three theses: genera and species are substances, genera and species are beings (onta in Greek), and genera and species exist thanks to primary substances. Chapter 7 of the Peri hermeneias shows the same way by stating that among things (ton pragmaton), some are universal and others are particular. The third text, which was unknown to early medieval realists, is Posterior Analytics II, 19 which was interpreted as describing the universal to be both an abstract concept, ‘‘the one apart from the many’’ (para t'a poll', unum praeter multa) and an immanent form which ‘‘is identically present in them all.’’ On the other hand, a philosopher who only believed in the existence of post rem universals could refer to the well-known passage from the De anima in which Aristotle states that the universal animal is either nothing or is posterior (I, 1 402 b720).

The medieval debate mainly focused on the admission or rejection of in re universals, and it did so within the framework of the exegesis of Porphyry’s Isagoge. In the Isagoge (ed. Busse, 1:10-15), Porphyry states - without giving his own answer - three questions on the ontological status of universals: do genera and species exist or are they only concepts? Are they bodies or incorporeals? Are they separated from the sensibles [i. e., the individuals] or do they exist in them? In this passage, Porphyry codifies the alternatives and possible answers to the question of the ontological status of universals (it is with this passage in mind that the theory of the three states of the universal was elaborated).

The history of medieval realism had ups and downs, quiet periods during which realism was an implicitly accepted doctrine that ended in crisis when virulent criticism cast strong doubts on the soundness of the theory. Roughly, we can identify three stages in the medieval history of realism. A first phase began with John Scottus Eriugena and lasted until the beginning of the twelfth century and William of Champeaux; this period ended abruptly with the powerful criticism of immanent realism by Peter Abelard. The second phase of development, that of the so-called moderate realism of the Doctors of Scholasticism, began at the University of Paris and included, in different ways, Robert Kilwardby, Thomas Aquinas, Duns Scotus, and the first Walter Burley; it was deeply shaken by William of Ockham’s questioning of the soundness of realism in any form whatsoever (Sent. I, dist. II, q. 3-7, pp. 74-266). However, realists were not led by Ockham’s criticism to abandon their theory, but proposed new versions of it - this is the third phase, illustrated by the late Burley, Wyclif, and their followers.

During the early Middle Ages, realism was mainly defended by four thinkers: John Scottus Eriugena, Odo of Cambrai, Anselm of Canterbury, and William of Champeaux, in his first theory of universals, the so-called material essence realism. There was no proper dispute about universals during the early Middle Ages until Peter Abelard; realism developed without being argued against a rival theory. However, early medieval realism does constitute a determinate metaphysical theory, which can be summarized in six theses. The theory states (1) the real existence of universals, that is, of the natural kinds to which particulars belong; (2) that universals do not exist separately from particulars; (3) that they constitute the substantial being of the particulars which are subordinate to them; (4) that a genus or species is entirely and simultaneously present in each of its subdivisions; (5) that the specific substance is common to all members of a species; and (6) that individuals of the same species are individuated by a unique bundle of accidents. In this theory, the universal man is taken to exist simultaneously in each of its particulars and to be fully realized in them. Socrates is composed of the universal man - which constitutes his essence, common to all the members of the species - and of a bundle of accidents, the collectio proprietatum in Anselm’s words. There is no essential individuation of particulars. An individual does not have its own essence - essential being is provided by the specific universal. From the point of view of substance, Socrates is no different from man. The thesis of the complete realization of the universal in each individual follows Aristotle’s statement that substances do not admit of more or less. The theory also follows Aristotle’s immanentism since universals have no existence separate from individuals. In the case of Eriugena (Periphyseon 463A; ed. Jeauneau, vol. I, 32:887893) and in that of William, according to Abelard’s testimony (Logica ingredientibus, ed. Geyer 12:27-32), this realism goes with realism about the categories that are described as being the ten highest genera of being, decem genera rerum in Eriugena’s words.

In the thirteenth century, a different kind of realist theory appeared. The intellectual background of this period was very different from that of the early Middle Ages. The thirteenth century is characterized by the rediscovery of the entire corpus of Aristotle’s writings and the beginning of the practice of quaestio in the recently founded universities. This in turn implies organizing arguments into pro and contra, and leads to an increased determination of positions, and through more explicit distinctions, to a higher degree of technicality of positions. The discovery of Avicenna’s writings provided two central new doctrinal elements: the theory of the three states of the universal and Avicenna’s distinction between a nature as such and the universality that a nature can have in the mind. Animal in itself is taken to be neither universal nor particular - to quote a famous saying: ‘‘Horseness (equinitas) is only horseness’’; the nature is neutral to either extramental or intramental existence. However, if to this nature are added spatiotemporal accidents, one obtains an individual substance, but if the mind’s universality is added to it, one obtains the universal notion. Also, developments in philosophy of language mean that realist doctrines from that time also involved a semantic theory (from the twelfth century and Peter Abelard onward, to give a theory of universals is also, perhaps even primarily, to answer the problem of the reference of common names). Besides some ‘‘generous’’ ontologies, such as that of Robert Grosseteste, who posits among universals creative ideas in his commentary to the Posterior Analytics, and Albert the Great who, in his commentary to the Isagoge, explored in detail the theoretical possibilities of the Avicennian doctrine ofthe three states ofthe universal, the constitution of the so-called moderate realism can be observed. Although each philosopher who defends this type of theory does so through his own particular variation of it, a number of common points can be noted between the various representatives of what historians have taken the habit of calling the moderate realist view. This view has some features that can be found in various authors. First, the acceptance of the framework provided by the doctrine of the three states of the universal. Universals are clearly not self-subsistent entities, but exist only in particulars as their main metaphysical components. Disagreements persist as to their mode of being outside the mind. The most common opinion is that universals exist potentially (inpotentia) outside the mind, and actually (in actu) within the mind.

Although it touches the borders of what may still be considered as a realist theory, Duns Scotus’ theory of common natures (Ordinatio 2 d. 3 p. 1 qq. 1-6) deserves particular mention, partly in reason of the historical role it was to hold. His theory is based on two elements: the ‘‘common nature’’ (natura communis) and the principle of individuation, the ‘‘haecceity’’ (haecceitas) or individual differentia. Following Avicenna, Scotus holds that the common nature is ‘‘indifferent’’ to existing in any number of individuals, and in that way it is common; it is also prior to being universal or particular. But it has extramental existence only in the particular things in which it exists, and in them it is always ‘‘contracted’’ by the haecceity (the individual differentia, which is also called a ‘‘contracting differentia’’). So the common nature humanity exists in both Socrates and Plato, although in Socrates it is made individual (or contracted) by Socrates haecceity and in Plato by Plato’s haecceity. When the haecceity is combined with the common nature, the result is a concrete individual, like Socrates, that differs from everything else. The humanity of Socrates is particular and nonrepeatable, as is the humanity of Plato; yet, humanity itself is common and repeatable, and it is ontologically prior to any particular humanity. The mode of unity of the common uncontracted nature is a real unity that is ‘‘less than numerical unity.’’ However, common humanity does not exist in individuals. It has been suggested that the reason for which we can state that Socrates’ contracted nature is, in a way, ‘‘the same’’ as Plato’s contracted nature, despite the fact that contracted natures are completely individualized by the individual differentiae, is the following: Socrates’ contracted human nature retains a real potency to be the contracted nature of Plato, and vice versa, while this does not hold in the case of the contracted cat-nature of Felix.

The fourteenth century was a new golden age for realism, despite Ockham’s criticism. Burley, whose first theories had been criticized by Ockham, gave a new version of his theory, and Wyclif defended a realism that later inspired the movement of the Oxford realists and, in the fifteenth century, of the Prague realists. Burley holds that a universal actually exists in an individual, not as a singular, but as a universal. The universal exists wholly as one and the same in each individual belonging to it. (Burley describes as follows the position he upholds: ‘‘Alia est opinio, que ponit universale habere esse solum in suis singularibus et quod universale secundum se totum est in quolibet suo singulari’’ Tractatus de universalibus, ed. Wohler, 20:16-17.) According to Burley, the universal is one, not in the way in which an individual is one, but in a way that is peculiar to it. He distinguishes ‘‘numerical identity in the strict sense’’ and ‘‘specific or generic identity’’ which denotes a genuine identity relation, the relation which a universal bears to itself. He states that universals exist outside the mind and that they are really distinct in the individual, but rejects the thesis according to which the universal has separate existence. Wyclif holds that the universal really exists in the particulars and that it is identical to them (De ente in communi, Chap. 5, p. 58). There is a real identity between the universal and the individual, since they share the same empirical reality (that of individuals). Only reason allows us to distinguish in an entity that which is universal from that which is particular; this distinction is only formal. Universals are really (realiter) identical to, but formally (formaliter) distinct from their individuals. Universals and individuals are the same identical things if conceived as first intentions, and differ from each other if conceived as second intentions (i. e., considered as universals and individuals, in this case they have opposite constituent principles: communic-abilitas, i. e., the disposition to be common, and incommunicabilitas, the impossibility of being common, respectively). Wyclif’s theory involves a revised version of the three states of the universal: he states that a universal maybe (1) universal by causality, (2) universal by community (‘‘a thing shared by many supposits [individuals understood as bearer of universals and of accidents] such as human nature’’), or (3) universal by representation (De univ. i, 6-22). Wyclif’s thought was continued by the ‘‘Oxford Realists’’ - the Englishmen Robert Alyngton, William Milverley, William Penbygull, Roger Whelpdale and John Tarteys, the German Johannes Sharpe, and the Italian Paul of Venice.

See also: > Albert the Great > Anselm of Canterbury > Augustine > Categories > Eustratios of Nicaea > Ibn Sina, Abu ‘All (Avicenna) > John Duns Scotus > John Scottus Eriugena > John Wyclif > Peter Abelard > Platonism > Robert Grosseteste > Schools in the Twelfth Century > Universals > Walter Burley > William of Champeaux > William of Ockham