Imagination, Cogitation

I’ve been rereading Jean-Baptiste Brenet’s Transferts du sujet, an exemplary case study of the now mostly forgotten 14th century philosopher John of Jandun. John’s use and misuse of Averroes and the surrounding anti-Averroist controversies both turn out to have major relevance for the history of Western concepts of “subject” and subjectivity. The discussions involve a fascinating mix of psychology, epistemology, and so-called metaphysics.

After examining the relation between Aristotelian “intellect” and the body, the second major topic Brenet addresses has to do with the cognitive role of Aristotelian phantasia or “imagination”. A while back, I excerpted and commented on an essay of Brenet’s on imagination in Averroes (see Desire, Image, Intellect). More generally, this is an area where the Arabic and Latin traditions greatly expanded upon Aristotle’s rather minimalist account of these matters. To begin with, they divide phantasia into three aspects, or interrelated but distinct “faculties”: imagination proper, memory, and what Averroes calls cogitation (and Avicenna calls estimation), which is broad enough to cover most everyday “thinking”.

Aristotelian imagination in the narrower sense is explained as involving sensible forms or images that we experience without external sensation. Memory involves sensible images that are similarly independent of external sensation. Like imagination and cogitation, memory deals primarily with particular sensible things. Aristotle explicitly says that memory requires a living body, whereas the “intellect” (nous) associated with knowledge of universals does not inherently have such a dependency. I would say that instead of depending on the body or individual consciousness, Aristotelian intellect and universals depend on language, discourse, and what contemporary writers call the “space of reasons”. Cogitation on the other hand, like memory, is generally treated as individual and bodily, and some writers treat intellect in the same way.

“Cogitation” is a kind of concrete everyday thinking by individuals that works with particulars and accidental properties rather than universals and essences. This includes pretty much everything we call “thinking” in ordinary life. (Its etymological connection to the Cartesian cogito is no accident. Cogito in Descartes is a first-person verb, though modern people treat it as a noun. It has the same broad scope as cogitation in Averroes.) Averroes criticizes Alfarabi and Avicenna for making Aristotelian intellect too transcendental. Late in life, he also comes to criticize Ibn Bajjah for going too far in the other, “Alexandrian” direction of effectively reducing human “intellect” to an “imagination” that is considered to be inseparable from a material body.

Brenet asks, “What does an image do? It is concerned with the production of the universal and the active role of the individual in that genesis. At stake is not only the empirical basis of thought, but the motive efficacity of the phantasms in the intellective process, and their dynamic function in uniting the body and intellect” (p. 133, my translation throughout).

“This is a subject that Averroes raises many times in his Long Commentary. The rational soul, he writes, has to consider the ‘intentions’ existing in the imaginative faculty, just as the senses have to inspect sensibles. If we left the image out of the production of the intelligible, it would be necessary to admit that thinking is a direct operation of the agent intellect on the material intellect. But that is inexact. The image is an indispensable subject of intellection and ‘one cannot say that the connection [rapport] of the agent intellect in the soul to the generated intellect is from every point of view like the connection of arts (artficium) to the artefact'” (pp. 133-134).

Intention is a concept from Arabic philosophy that was particularly developed by Avicenna. It acquired wide currency among the scholastics. This idea was rediscovered in the late 19th century by Brentano, and acquired wide currency in Husserlian phenomenology and analytic philosophy. Brandom credits Kant and Hegel with developing a non-psychological alternative account of intentionality.

“As intelligible species, ‘universals’ are concepts. What is proper to a species is in effect to ‘represent’. And if a sensible species represents a singular, an intelligible species represents an essence or quiddity (representitiua quidditatis). Concepts are produced. An intelligible species is not given from the outset or always already available. As ‘intention’, the universal is posterior to singulars. It does not exist outside of things” (p. 135).

A multitude of elaborate accounts and critiques of intelligible and sensible “species” were elaborated in the Latin tradition. Scholars have debated about the origins of the Latin term species (possibly Stoic?), but in any case, like the fine semantic distinctions of the theories of “supposition” and the far more heated but also highly sophisticated debates over various versions of nominalism and realism, this non-Aristotelian usage of the term “species” became a scholastic commonplace. It was not so much attributed to Aristotle as grafted into an already hybrid discourse. (Is there a discourse that is not hybrid?) More Aristotelian is the notion of “conceptualism”, a variant of which has been attributed to Peter Abelard.

“It is indeed in the intellective soul that the stone exists, or the human, and not in nature. The universal is something intellected, which can neither be really separated from the beings with which it is concerned nor really confounded with them. It is this conceptualist thesis, directed against Plato, which serves as the theoretical sub-basement for John of Jandun’s questions on noetics, that is to say the idea, derived from the Aristotelian distinction of the two intellects, of a production of intelligible thought as abstraction. But what is the detail of this operation?” (p. 136, emphasis in original).

The idea here is that universals are something rarefied and actively constituted, rather than something commonplace that is somehow given to us. All sensible things are regarded as particular. Ordinary life arguably deals only with particulars, like the peasant with her cows at the beginning of Hegel’s Phenomenology. Aristotelian ethics meanwhile emphasize goodness of fit to the particulars in any situation.

This is complicated by the simultaneous non-Aristotelian discourse about species, which on some accounts precisely are supposed to be ubiquitous and given. Medieval species are paradoxical because they are alternately treated as universals and as objects. But either way, they are often supposed to be natural and/or God-given.

On the more active side, there are developments out of the Aristotelian notion of “abstraction”, which is supposed to be a process by which universals are derived from particulars. Some accounts make it sound like this just happens. There is a common interpretation that identifies abstraction with a simple logical induction of generalities from particulars. All dogs have four legs, and so on. But both “Alexandrian” and “Averroist” readings of Aristotle treat abstraction as a process of progressive removal of accidental properties, or progressive distinction of the essential from the accidental. This is sometimes called “geometrical” abstraction, due to the way geometry uses figures to represent universals. Aristotle’s minimalism on this key question led to many creative elaborations by later writers, from Alexander of Aphrodisias (late 2nd/early 3rd century CE) to Zabarella (late 16th century).

Brenet notes that many of the more detailed later accounts of Aristotelian abstraction are expressed in terms of expanded accounts of imagination, memory, and “cogitation”.

John of Jandun “asks if intellect is a virtus passiua [passive virtue]. We know his answer: there is in the human intellective soul a passive ‘power’, the possible intellect, which permits it to receive the intelligible species and thought. It is passive because it is moved by something ‘extrinsic’ to it, the human phantasm, without which intellection cannot occur…. It is absolutely necessary that the images ‘move’ the intellect for it to pass to the act of thinking…. This means that intellection comes down to passivity, to the intelligible mediante phantasmate [mediating phantasm]…. It is clear, as a consequence, that the image intervenes as motor in the intellective process, by making an intelligible species arise in the possible intellect” (pp. 136-137).

The “human phantasm” is basically coextensive with experience. Meanwhile, intellection is construed narrowly as concerned with universals. So when Brenet says that intellect for John is a passive virtue, this does not mean there is no activity in broader human thinking. The whole discourse about “production” of intelligibles makes the classic Aristotelian point that forms are not just “given” to us.

“For what is it that can produce the species that the intellect finally has need of to exercise itself? It is not the species present in the sensitive faculty of the individual, it is not the possible intellect, it is not solely the agent intellect, it can be nothing else than the phantasm. The sensible species is incapable of that, because it is not ‘spiritual’ enough, i.e., not close enough to the nature of the immaterial intellect. The possible intellect, which is a pure power of reception, cannot do so either. As for the agent intellect, it cannot be since it is the universal cause of all the species” (p. 137).

“If a phantasm is found in the imagination of an individual human, an intelligible species is received in the intellect; if the phantasm disappears, the intelligible species disappears with it…. And we can deduce that the image is to the intelligible species as the light of a luminous body … is to the illumination of the transparent medium: … an active cause (causa activa)” (p. 139).

“Universals are colligata [bound up with] imagined intentions. Is this to say that they are vaguely related, without being able to make precise the nature of the relation? John’s whole demonstration aims to show on the contrary that the image and the species in the intellect maintain a relation of principle and product…. This conditioning is a relation of causal genesis in which the image is given a motive efficacy” (p. 140).

“The image can indeed intervene as a motor in the production of the intelligible species. But it does not act alone” (p.142). “The image by itself is powerless to exceed its singularity, to transmute itself, to yield the intelligible species” (p. 144). “The agent intellect is necessary for the image to be related as cause to a product, the intelligible, whose nature surpasses its own” (p. 145).

“The universal form is taken from the image by the intellect, issue of their synergy: without the phantasm, intellect turns emptily, and without the intellect, the phantasm is unable to limit itself” (pp. 145-146).

That sounds like a famous quote from Kant about the interdependence of what he calls understanding and intuition.

“But what does the agent intellect ‘do’ when it intervenes on the image?” (p. 146). “We know the point of departure (the image) and the point of arrival (the intelligible species), and the necessity of the passage from the one to the other under the action of the intellect. But the modality of the transfer stumbles. The intelligible species is not already in the image, like an accident of imagination that the intellect has the function of de-subjectifying and de-localizing in depositing in the intellectual receptor. It is indeed not the intelligible species that is displaced by the agent from one order to another” (p. 148).

“The agent intellect and the image are both necessary for thought…. It is on the singularity of an image that the power of the agent intellect must be exercised if we want to think something. Images alone do not suffice for thought, which would come back to something confounding the individual and the universal” (p. 157). But according to Brenet, John rejects the view that “As a consequence, without contact, without influx, the presence of the agent intellect allows an object to appear, and an object of thought” (p.158).

“The mere presence of the agent intellect cannot make one intention rather than another modify the material intellect. For abstraction is impossible unless it is preceded by a separation of objects. Because it is always singular, the very act of thinking presupposes this exclusivity and this determinate modification: all thought is the thought of an image, or of a quiddity of images. It is not sufficient to put the agent intellect in the presence of a mass of phantasms for a thought to take place. For a thought to take place, it is necessary to explain why it is on this image that it is exercised” (p. 161).

John argues against Thomas Wilton that “It is intellect that gives objects to the will, and not the inverse” (ibid). “When [Averroes] affirms that we abstract and think when we will it, in reality, explains John, it is necessary to understand: when we cogitate, i.e. when we make use of the cogitative faculty that is proper to us. It is the cogitative that separates the imagined intentions” (ibid). “The truth, for John of Jandun … is that the cogitative ‘cogitates’ the individuality of a quiddity to the exclusion of another and that, in doing so, it disposes the possible intellect to think that quiddity” (p.162). John complains that Wilton “ignores the determining role of the virtus cogitatiua in the separation of individual intentions” (ibid).

“John of Jandun’s ‘solution’ is in effect the following. The phantasm acts in the possible intellect in producing the intelligible species and does so alone, without competition. It is the immediate cause and the unique active principle of that species” (p. 165, emphasis in original). “The individual imaginative faculty is the sole cause of an intellectual product…. From the process of production of the intelligible, in any case, the agent intellect is absolutely excluded” (p. 166). “The phantasm causes the intelligible species, and that is all. It is a motor, it moves the intellect in making the species. Nothing is said of the mode of its intelligibilization, of its genesis…. The production of the intelligible form is nonintellectual…. If abstraction is equated with producing the universal species, then the agent intellect does not abstract the intelligible” (p. 167, emphasis in original).

“The Parisian master indeed seems to reject the idea that the intellect has a connection with the image: it is certainly the abstracter, it is in this very capacity that it is united from the outset to the thinking individual; but not every abstraction is a universalization of forms and, in a certain sense, when the agent intellect ‘abstracts’, it acts on a form that is already universal. It is thus without direct connection to the phantasm — it does not act on it, or on the possible intellect, but on the product deposited in that intellect from the activity proper to the phantasm” (pp. 167-168).

“The phantasm alone is the principle of the intelligible that precedes thought” (p. 174). “The singularity of [John’s] reading lies in the fact that intellectual abstraction designates not the intelligibilization of the phantasm, but the intellection of what is intelligized…. This abstraction is not the act that assures the production of the intelligible, but that which operates the effectuation of its representative function” (p.175).

“What is left of the Long Commentary on the De Anima and of Averroes? Hardly more than words. For John, the image is endowed with an autonomous and self-sufficient motricity; the intelligible, although produced, precedes any intellectual intervention; and the intellect is no longer an abstracter save in name only, deprived of any connection to intelligibilization” (p. 176).

“Two things, at least, can be deduced from the preceding analyses. First, there is no unified Averroist doctrine of abstraction…. Second, the hypothesis of the ‘Averroist’ John of Jandun on abstraction is not at all Rushdean” (ibid).

Brenet says that in fact John’s formulations on abstraction have an unrecognized strong connection to the thought of Duns Scotus, who also holds that the universal in act precedes the act of intellection.

Next in this series: Cogitation, Intention

Averroes as Read by de Libera

Alain de Libera has played a major role in reviving interest in Averroes. In 1999 he published a French translation of the crucial book III of the famous (or infamous) Long Commentary on Aristotle on the Soul, which was the first rendering of this work into a modern language. He devotes an 80-page chapter of Archéologie du sujet volume 3 part 1 to reconstructing the more controversial parts of this long-misunderstood text. I’ve previously discussed the reading of Deborah Black in “This Human Understands”, and that of Stephen Ogden in “This Human”, Again.

The modern notion of a subject-agent, de Libera says, originated partly in opposition to Augustine and partly in opposition to Averroes. Though he was responsible for first introducing a notion of “subject” into Aristotelian discourse about the soul, Averroes did not introduce the “modern subject”. According to de Libera, the notion of the human as subject-agent of thought was developed first in opposition to Averroes, then in opposition to the Averroists, then by later Averroists responding to criticism.

“[F]or an Aristotelian as for a Plotinian, the intelligibles in act are not mental states, accidents or accidental forms of a mind posed as substrate and having before it things, themselves bearing qualities, but the intelligibles themselves as intellects in act” (p. 166; my translation throughout). I’ll try to shed some further light on this below.

De Libera cites Aristotle’s own statement that intellect and the intellected are one. He says Averroes’ Latin readers were misled by Michael Scot’s translation of intellectus (intellect as a faculty) for what should have been intellectum (the intelligible). The thesis of the unity of intellect commonly attributed to Averroes is really at its root a thesis of the unity of the intelligible, he says. Averroes primarily has in mind Plato’s problem of how teaching and learning — and shared apprehension and objectivity — are possible.

“The first concern of Averroes is to escape from Platonism” (p. 182). This means we still like forms, but we do not posit free-floating Forms. Aristotle’s alternative is a theory of “abstraction”. Intellect is said to “abstract” intelligibles as universals from the concrete particular contents of what is called imagination. De Libera says that Aristotle used both inductive and “geometric” notions of abstraction, but notes that the commentator Alexander of Aphrodisias particularly emphasized the “geometric” version, which is said to involve conceiving as separate from matter the forms that are nonetheless not separate from matter.

“The noetic problem inherited from Alexander by Averroes is above all that of the production of the intelligible in act: the intentio intellecta” (p. 184). “Intellect is not mind. Nor is it consciousness” (p. 185). The intentio intellecta is not the intentionality arising from the act of a transcendental Ego that Husserl spoke of.

“What is this problem? Not that which Thomas posed to the Averroists, and through them to Averroes: to account for the fact of experience that I think, but rather: to account for the fact that we think, or better, the fact that we think or are capable of thinking the same thing.”

“At issue here is neither the I, nor the human, nor the individual human, but indeed the I and the you” (p. 186). De Libera suggests the analogy of Fregean thought that “is independent of our activity of thought” (p. 187), and says that like Frege, Averroes “opposes thought, intellectio, to representation, cogitatio” (ibid).

The Greek commentator Themistius had suggested underwriting the unity of the intelligible by a unity of “intellect”.

“[T]he theory of the unity of the material intellect has the function of resolving, from a strict Aristotelian point of view, the Platonic question of the possibility of teaching and apprenticeship” (p. 189).

Averroes wants to say that the intelligible is both one and multiple. We can apprehend the very same thing, and yet do so separately. In the forms in our incarnate imaginations it is multiple, but in the immaterial “material intellect” it is one.

Averroes referred to both the imagined, represented, or “cogitated” forms in the soul and to the so-called material intellect with a word that was translated to Latin as subjectum or “subject”. His account of how the two “subjects” interact has become known in secondary literature as the “theory of the two subjects”. Though it was being applied to human imagination and thought, the notion of subject here was understood by his Latin readers as just the abstract one of something standing under something else.

De Libera says it is impossible to understand the theory of two subjects without paying attention to what Averroes says about two related movers. In a famous development in the Metaphysics, Aristotle himself progressively sublimated the “standing under” concept, ultimately replacing it with considerations of potentiality and actualization. De Libera says that in Averroes’ reflections on intellect, “subject” really means mover rather than substrate.

An Aristotelian mover is actually very different from the modern concept of an agent. De Libera quotes Aristotle to the effect that “movement, action, and passion reside in that which is moved” (p. 198).

Averroes, following Aristotle, develops an analogy between sense and intellect. De Libera analyzes Aristotle’s account of the case of sense in four points: 1) that which is potentially sensible exists independent of sense; 2) it only plays the role of mover in the sensitive faculty; 3) the sensible in act (or the sensed) and the sensing or the sense in act are numerically the same act, but differ in essence or quiddity; 4) the identity of the act of the sensible and the act of the sensing in the sensing serves as Aristotle’s explanation for how we sense that we are sensing, or how we have internal sense. In this “synergetic” account, sensation is not a pure passive reception, but rather at the same time is an actualization of a potentiality that we have, and indeed an actualization of us.

De Libera notes that the analogy Aristotle and Averroes both make between sense and intellect in this regard is already enough to invalidate all the readings of Averroes that make the human entirely passive in relation to thought. Intellect for Averroes is not a simple “Giver of Forms” like the transcendent intellect in Avicenna. According to de Libera, in sensation only the potentiality of the sensing functions as a subject of inherence or attribution. That which is potentially sensible does not sense. Similarly, in intellect the intentio intellecta has only one subject of inherence or attribution, which is the potentiality for intellection in the so-called material intellect. That which is potentially intelligible does not think. Nor are intelligibles “emanated” directly to the soul, any more than sensations are received in a purely passive way.

“The receiving intellect is not a sponge. It moves itself. Or better, it is moved. Its movement is a motion by final cause” (p. 212). The two movers in this case are the forms in imagination and the abstracting “active” intellect.

“The human is not the subject of thought, but nonetheless she thinks, and thinks at will. Such is the thesis of Averroes” (p. 215). We think when we want. For Averroes, the agent and receptor of the intelligible in act are both eternal, separate substances, but the activities of these separate substances nevertheless take place in us, and are attributed to us. This should correct the misleading impression that for Averroes what the moderns call “the subject” is divided into a part that is mental but not thinking, and a part that is thinking but not mental. It is even further removed from the argument of Aquinas that Averroes makes the human into something like a wall, and into something passively thought by something else rather than something thinking.

Thought in the human is a habitus, or Aristotelian hexis. This is a “second actuality” or “second perfection”, a product of processes of actualization. Averroes makes significant use of the notion of the “acquired intellect” that may come to be immanent in the human, which was explicitly elaborated by al-Farabi using Aristotelian notions of potentiality and actualization. In this context de Libera speaks of production and re-production, actualization and re-actualization. It is by virtue of having this “acquired intellect” that the human has the ability to think when she wants.

“The one who has thoughts thinks” (p. 219). “Active” and “material” intellects are two faculties or moments of one thing or process. We act by means of them, and according to de Libera this means that for Averroes, they constitute our form insofar as we are thinking. Averroes holds that Aristotle’s use of “soul” is equivocal with respect to whether or not it includes intellect; that only the animal and vegetable parts of the soul count as form and first perfection of the body; but that intellect nonetheless is our form when we are thinking.

Searching for a Middle Term

“But nothing, I think, prevents one from in a sense understanding and in a sense being ignorant of what one is learning” (Aristotle, Posterior Analytics; Complete Works revised Oxford edition vol. 1, p. 115). The kind of understanding spoken of here involves awareness “both that the explanation because of which the object is is its explanation, and that it is not possible for this to be otherwise” (ibid). To speak of the “explanation because of which” something is suggests that the concern is with states of affairs being some way, and the “not… otherwise” language further confirms this.

Following this is the famous criterion that demonstrative understanding depends on “things that are true and primitive and immediate and more familiar than and prior to and explanatory of the conclusion…. [T]here will be deduction even without these conditions, but there will not be demonstration, for it will not produce understanding” (ibid). The “more familiar than” part has sometimes been mistranslated as “better known than”, confusing what Aristotle carefully distinguishes as gnosis (personal acquaintance) and episteme (knowledge in a strong sense). I think this phrase is the key to the whole larger clause, giving it a pragmatic rather than foundationalist meaning. (Foundationalist claims only emerged later, with the Stoics and Descartes.) The pedagogical aim of demonstration is to use things that are more familiar to us — which for practical purposes we take to be true and primitive and immediate and prior and explanatory — to showcase reasons for things that are slightly less obvious.

Independent of these criteria for demonstration, the whole point of the syllogistic form is that the conclusion very “obviously” and necessarily follows, by a simple operation of composition on the premises (A => B and B => C, so A=> C). Once we have accepted both premises of a syllogism, the conclusion is already implicit, and that in an especially clear way. We will not reach any novel or unexpected conclusions by syllogism. It is a kind of canonical minimal inferential step, intended not to be profound but to be as simple and clear as possible.

(Contemporary category theory grounds all of mathematics on the notion of composable abstract dependencies, expressing complex dependencies as compositions of simpler ones. Its power depends on the fact that under a few carefully specified conditions expressing the properties of good composition, the composition of higher-order functions with internal conditional logic — and other even more general constructions — works in exactly the same way as composition of simple predications like “A is B“.)

Since a syllogism is designed to be a minimal inferential step, there is never a question of “searching” for the right conclusion. Rather, Aristotle speaks of searching for a “middle term” before an appropriate pair of premises is identified for syllogistic use. A middle term like B in the example above is the key ingredient in a syllogism, appearing both in the syntactically dependent position in one premise, and in the syntactically depended-upon position in the other premise, thus allowing the two to be composed together. This is a very simple example of mediation. Existence of a middle term B is what makes composition of the premises possible, and is therefore what makes pairings of premises appropriate for syllogistic use.

In many contexts, searching for a middle term can be understood as inventing an appropriate intermediate abstraction from available materials. If an existing abstraction is too broad to fit the case, we can add specifications until it does, and then optionally give the result a new name. All Aristotelian terms essentially are implied specifications; the names are just for convenience. Aristotle sometimes uses pure specifications as “nameless terms”.

Named abstractions function as shorthand for the potential inferences that they embody, enabling simple common-sense reasoning in ordinary language. We can become more clear about our thinking by using dialectic to unpack the implications of the abstractions embodied in our use of words. (See also Free Play; Practical Judgment.)

“Absolute” Knowledge?

The term “absolute” in Hegelian absolute knowledge refers only to a certain finality and stability of its form, not to any claim of infallibility or omniscience on the side of content. Intended for earthly actualization and thus finite in that sense (as distinct from Hegel’s sense of “finite” as what is viewed in isolation), it also does not involve any infinite or immediate reflexivity. As a first approximation, it is simply the result of a thorough renunciation of implicit pretensions of Mastery — that is to say, it is a result of the abstraction or subtraction of something from ordinary knowledge, not of the acquisition of some kind of super powers.

At the risk of courting paradox, it might be said that “absolute” knowledge is absolute precisely because it recognizes itself as relative, and true freedom is freedom from false freedom.

This is related not only to an abstract recognition that finite concepts in general are provisional and that understandings in general are context-dependent. It is also requires concrete recognition that each finite concept we actually use is in principle provisional and subject to question, and that each understanding we actually rely on implicitly involves a dependence upon context, therefore also on an assessment of context that can be questioned.

Hegel offers two further developments of this. The first is associated with the perspective that “substance is also subject”. The second is a related one involving overcoming modern thought’s characteristic separation of subject and object. While the mention of either of these may initially raise further questions, they are not difficult to grasp once explained. (See also Rationality.)

Nominalist Controversies

Especially in the 14th century, controversies associated with the opposition between nominalism and realism greatly exercised philosophers and theologians in the Latin West. These terms have been been variously understood, but as a first approximation, nominalism wants to deny claims about the real basis of abstractions that the realism of this context wants to affirm.

In this case, a polar opposition is concealed behind a pair of concrete terms (nominalism, realism), where in context one is understood as the simple negation of the other. As usual with debates around distinctions based on polar opposition rather than more limited and definite determinate negation, the greatest interest often lies in the way each side tries to recover something like the strong points of the other side, but in its own terms.

These controversies are worth lingering over for several reasons. For one thing, they help illustrate the great diversity, subtlety, and liveliness of medieval thought. For another, they develop many fine distinctions that are of lasting value in talking about human knowledge and understanding. We would all like to rightly apprehend things, whatever that means. The waters are commonly muddied not only by insufficient distinctions among things, but also by fundamental unclarity or ambiguity on the meaning of “existence” or “reality”, which gets worse where abstract things are involved. Who we might think was right in the debates is of secondary importance compared to clarifications of this kind. Finally, these debates involved much discussion of mental representation, its origins, and its role in thought.

Speaking with very broad brush, nominalism begins as a critique of a sort of “platonism”. Such platonism wants to say the universal is more real than the particular. It may go on to claim that abstract entities are as real as — or more real than — concrete ones. It may extend to further claims that universals simply “exist” in some pure way, independent of space and time. Nominalism in general wants to say the opposite, that universals are actually not real at all.

Aristotle already criticized platonist views of the sort just mentioned, while still maintaining that the development of universals is essential to knowledge. I think that in the big picture, he wanted to recommend an essentially even-handed approach, recognizing both universals and particulars as necessary to any developed view of experience, while pointing out their very different and complementary roles. Whatever we may think about the reality or unreality or existence or nonexistence of given things or of various kinds of things, we need universals to support the implicit reasoning standing behind any developed knowledge. We also need particulars as practical starting points, and as cross-checks to keep us honest. This does not yet make any claim about reality or existence that might support such needs. Aristotle often practiced a careful minimalism, sticking to essentials and leaving other questions open, and this is a good case in point.

Albert the Great and Thomas Aquinas wanted to develop Aristotle’s position into a firmer doctrine, classically called moderate realism. Most people agree that Aristotle thought universals do not “exist” independently of particular things and thought. Albert and Thomas argued that implicitly, what Aristotle said committed him to 1) a claim that universals are real and 2) a claim that universals exist, but only in concrete things and in thought.

Nominalists especially disputed the claim that universals exist in concrete things. They most commonly advocated a mental origin of universals, while differing on the precise status attributed to them. Already in the 12th century, Roscellinus had argued that universals are mere names (root of the word “nominalism”). Whether or not the great Peter Abelard should be interpreted as a nominalist or a middle-of-the road “conceptualist” is contested among scholars.

The theologian William of Occam (1285 – 1347) was the most famous medieval nominalist. Early in his career, he argued that universals were ficta (“fictions”) of the mind. Later, he worried that this still tacitly presupposed they were representations, which would seem to still imply something corresponding to them in external objects. He then argued that external objects have causal impact on the mind, but not by representation.

The important secular master John Buridan (1301 – 1358) is usually also called a nominalist. Buridan was one of the leading logicians of the middle ages, and wrote on a wide range of philosophical questions. He had several noteworthy students who are also considered nominalists, including the logician, natural philosopher, and bishop Albert of Saxony (1320 – 1390). Marsilius of Inghen (1340 – 1396) was another nominalist who wrote on logic, natural philosophy, and theology. The theologian Gregory of Rimini (1300 – 1358) is also considered a nominalist.

The great theologian John Duns Scotus (1265 – 1308) was a commited realist who nonetheless influenced Occam on some relatively unrelated points. The influential Walter Burley (1275 – 1344) is sometimes called an extreme realist. Paul of Venice (1369 – 1429) was formerly classed as a nominalist, but is now considered a realist.

Among those who were called nominalists, there were many different views and distinctions related to the complex medieval theories of sensible and intelligible “species”. In one aspect, these were mental representations, but theories of sensible species usually had a physical component loosely inspired by Stoicism. Occam denied species, while Buridan made use of them.

From the 12th century onward, Latin philosophers developed sophisticated original theories of the different kinds of “supposition”, or generic ways in which something said can be meant. The general notion was that the kind of supposition that should be read into a concrete utterance should be determined by analyzing the context of the utterance in various ways. This was basically a kind of semantics. What is perhaps surprising is that broadly similar supposition theories were largely shared by dedicated nominalists like Occam and commited realists like Walter Burley, providing a common vocabulary.

On a side note, Occam’s causal impact theory seems problematic from the point of view of the development here. While its avoidance of dependence on representation is attractive, a direct causal link from external objects to thoughts does not seem adequate to account for the full range of diversity of thoughts. Also, there seems to be an incipient mentalism already at work here, related to that of Avicenna.

Occam was a theological voluntarist and a fideist. Fideism is the belief that faith offers a kind of knowledge superior to reason, an extreme position that was repeatedly condemned by the Church. Occam has nonetheless often been named as a major precursor of the point of view of modern science. Even though some connections can be made, this seems questionable as well, given his mainly theological intent and the character of the theology he promoted.

Abstraction

Abstraction in Aristotle is sometimes made out to be mysterious. I think it is just straightforward subtraction of features of a thing that have been previously recognized as “accidental” for the pertinent context of evaluation. Abstraction is neither a way of magically laying bare the true inner essence of a thing, as envisioned by some medieval realists, nor the mental creation of a universal ex nihilo, as envisioned by some nominalists. It is also does not have any necessary dependency on induction.

What counts as accidental may vary with the context of evaluation. While distinctions of essence and accident are fairly stable within a given context, they are ultimately relative and contextual. The pertinent context includes not only contingent facts about what is being evaluated, but also the purpose of the evaluation.

In other, non-Aristotelian contexts, Badiou has recently made it somewhat fashionable to speak literally about “subtraction” instead of “abstraction”. Though I have many issues with his thought, this is actually a useful clarification.