The Condemnation of 1210
1The story of the spread of Aristotelianism in the Latin Middle Ages is rather well known, even if we are still missing many of the links and intermediaries, most often for lack of any evidence, that might serve as a foundation. And yet it is still quite diverting. Before the statutes of 1252 and 1255, which give their blessing to teaching Aristotle’s natural philosophy, Aristotle’s Libri naturales were already making extensive inroads into philosophical and university milieus. Even before the Latin translations of Averroes by Michael Scot in the years 1220-1230, beginning in the middle of the twelfth century, a large number of translations and commentaries begin to circulate. Their authors are little known, however. Such is the case with David of Dinant, particularly famous due to the Parisian decree of 1210 (confirmed, five years later by Robert de Courçon’s statute), which orders his works to be burned and simultaneously forbids the “reading” of Aristotle’s Libri naturales. 
2Little is known about David of Dinant, and, until relatively recently, his Quaternuli were only known from the excerpts or summaries given by Albertus Magnus or Thomas Aquinas, which made it difficult to develop any proper idea about them. For the record, let us mention G. Théry, who, in 1925, proposed a list of these passages to try to reconstruct David’s lost work, and arrives at the conclusion that David must have been a teacher at the university of arts, a logician without physical or metaphysical preoccupations: from Aristotle’s Metaphysics he may have borrowed “verbal” definitions lacking real content, and used them “with the consummate artistry of a dialectician.”  For lack of a better source, Théry was obliged to come to terms with the extremely violent judgments by Albertus Magnus, who does not fail to contrast David’s “sophisms” with Aristotle’s “genuine” philosophy. For Albertus, it was necessary to show that the condemnation in 1210 (and then in 1215) of Aristotle’s Libri Naturales rested on a misunderstanding: David’s scandalous theses are in no way Aristotelian. Several decades later, Thomas Aquinas reprises, in substance, this thesis. Théry, who follows this route traced by Albertus and Thomas, tries to show that David’s “pantheist materialism” must rather be placed next to the “Eleatic” theses criticized by Aristotle in Book A of Metaphysics (Xenophanes, Parmenides, and Melissus); and his analysis of the evidence leads him to maintain that David commits two fundamental errors: 1) “his unilateral and simplistic mind did not understand the theory of analogy.” Indeed, he did not understand that if matter and form exist, it is not “in an identical manner, but analogically”; 2) he deprives the forms of all “true existence,” making them out to be “appearances” or “accidents” of being, and in this way calls into question diversity in the world (Théry 31). In perfect Thomistic form, Théry ultimately invokes, against David, two doctrines not found in Aristotle: that of analogy and that of substantial forms.
3Excerpts from David’s Quaternuli were rediscovered in the early 1930s by A. Birkenmajer and published in 1963 by M. Kurdzialek;  and, since then, it has been possible to revise the interpretation that Théry gave of the evidence at his disposal. David is not a “pure dialectician,” only using a few short excerpts from Metaphysics or Physics as his basis. He is the complete opposite. The manuscripts show that David has a firsthand and rather vast knowledge of the Aristotelian corpus. There we do indeed learn that “teacher David” traveled to Greece (to Constantinople) where he was able to read the crucial parts of Aristotle’s “natural” treatises.  This is a remarkable feat at a time when a lot of translations tend to be based on Arabic versions of Aristotle. The rediscovered Quaternuli manuscripts are presented as a mixture of translations of varying lengths as well as commentaries: cited, pell-mell, are zoological and biological treatises, the Meteorology, the Parva Naturalia series, De Anima, Physics, De Caelo, as well as Problemata. Far from being a “pure” logician, David therefore appears to be more of an authentic “naturalist.” Like, moreover, the majority of the first translators of Aristotle, his approach is deeply influenced by medical problematics.  And thus, the text that opens the Ghent manuscript is an almost full translation—to our knowledge, the first in Latin—of the celebrated Problem XXX, 1 on melancholy (Dinant, 3–4). This text, so perplexing for theologians in the second half of the thirteenth century, serves here as an introduction to Aristotle.  From this perspective, one can quite logically follow Albertus Magnus when he presents David as a reader of Alexander of Aphrodisias (a hypothesis rejected, however, by Théry). Thus we read in the Compilatio de novo spiritu (attributed to Albertus): “Dicere quod omnis creatura sit Deus, heresis Alexandri est, qui dixit, materiam primam et deus et noym, hoc est mentem in substantia (unam substantiam esse) quem postea quidam David de Dinant secutus est” (“Claiming that every creature is God, this is the heresy of Alexander who said that that the primary substance, God, and the nous, that is to say, the substantial intellect, are a single substance, Alexander was later followed by a certain David of Dinant” ).
The Fragment <Mens, Hyle, Deus>
4The text that we propose to examine here is particularly dense in its argumentation. It consists of a passage where we find most explicitly formulated the “pantheistic” and “materialist” thesis, which, if we are to believe Albertus Magnus, led to the scandal. The other passages from manuscripts rediscovered by A. Birkenmajer that one could invoke are even more elliptical (see Dinant 88).
<Mens, hyle, Deus> Dico igitur tria esse in anima: scientia et intellectum et voluntatem; horum autem unumquodque est passibile. Dico passibilem scientiam esse sensum, passibilem vero intellectum ymaginacionem, passibilem vero voluntatem desiderium seu affectum.Nam sensus nichil percipit quam passionem que fit in instrumento sensus a re sensata. Quoniam vero ymaginacionem impossibile est fieri nisi ex preexistente sensu, manifestum est, quod ymaginacio nichil aliud percipit quam signum vel vestigium passionis sense. Sed nec affectus potest fieri in anima nisi immutacionem <sistoles> vel diastoles, sive secundum calefactionem vel frigefactionem sanguinis, sive spiritus qui est in corde. Querit autem Aristoteles, utrum aliquid de anima separabile sit a corporre.Igitur nullum trium predictorum posse fieri nisi a corpore, quando nullum horum fit nisi cum passione corporis. Subinsunt: aut de anima nichil esse separabile, aut non.Aliquid est separabile in anima a corpore in esse, quod nos mentem dicimus. Unde manifestum est, mentem esse quod impassibile in quo sunt memorata tria eo, quod impassibile sunt. Dico autem, quod quemadmodum se habet corpore ad ylen, ita se anima ad mentem: si autem sint corpus et yle passiva, ita anima et mens passiva.Dico autem, quod una sola est mens, multe vero anime; et una sola yle et multa vero corpora. Cum enim sole passiones, hoc est accidencia sive proprietates, faciant differenciam rerum ad se invicem, necesse est unum solum esse id, quod nulli passioni subiectum est; cuiusmodi sunt mens et yle. Ea vero, que passiva sunt, necesse est esse multa, et quod proprietates, que in ipsis sunt, faciunt differenciam ad alterum (cuiusmodi sunt corpora et anime), manifestum est, quod una sola est mens et una sola yle. Querendum autem, utrum mens et yle unum sint, aut diversa. Cum igitur sola passiva differant ad se invicem, videtur mentem et ylen nullo modo differe, cum neutrum eorum sit subiectum passioni. Rursum autem, quemadmodum passivus intellectus, qui est in anima, comprehendit solum corpus, ita et impassibilis intellectus, qui est in mente, comprehendit solam ylen. Manifestum est etiam, quod passivus intellectus (hoc est imaginacio) non comprehendit esse, nisi assimiletur rei sense, nam hoc supra naturam; per simile vero videtur, quod nec [im]passibilis  intellectus possit comprehendere ylen, nisi habeat similitudinem cum ea aut ei sit idem. Non autem potest esse similis, cum similitudo non sit nisi eorum, que passiva sunt et sunt subiecta eidem passionis, cuiusmodi sunt duo alba aut duo nigra. Ex hiis ergo colligi potest mentem et ylen idem esse. Huic autem assentire videtur Plato, ubi dicit mundum esse <Deum> sensibilem. Mens enim, de qua loquimur et quam unam dicimus esse eamque impassibilem, nichil aliud est quam Deus. Si ergo mundus est ipse Deus preter se ipsum perceptibile sensui, ut Plato et Zeno et Socrates et multi alii dixerunt, yle igitur mundi est ipse Deus, forma vero adveniens yle nil aliud quam id, quod facit Deus sensibile se ipsum. Nam quantitas, ut ait Aristoteles, primum est adveniens yle et fit corpus; corpori vero advenit naturalis et fit elementum. Cum enim yle vi sui nature sicut imperceptibile et immobile, sensus tamen recipit magnitudinem et motum in ea. Manifestum est igitur unam solam substanciam esse, non tantum omnium corporum, sed etiam animarum omnium et eam nichil aliud esse, quam ipsum Deum. Substantia vero, ex qua sunt omnia <corpora>, dicitur yle; substancia vero, ex qua sunt omnes anime, dicitur racio sive mens. Manifestum est ergo Deum esse racionem omnium animarum et yle omnium corporum.
I therefore say that there are three [faculties] in the soul: science, intellect, and will (scienciam, intellectum et voluntatem). Each of them is passive (passibile). I say that passive knowledge is sense, that the passive intellect (passibilem intellectum) is the imagination, and that the passive will is desire or affection. For sense perceives nothing other than the passion produced (que fit) in the instrument of sense by the thing sensed. And since it is impossible for the imagination to take place (fieri), unless from a preexisting sensation, it is manifest that the imagination perceives nothing other than the sign or the trace (signum uel uestigium) of a sensible passion (passionis sense). But affection cannot occur in the soul either, unless by alteration (nisi per immutaciones) of the systoles and diastoles, through the heating or cooling of the blood or of the spirit that is in the heart. Aristotle nevertheless wonders whether something of the soul (aliquid de anima) is separable from the body. None of the three [faculties] mentioned can occur (posse fieri), except with the body as their basis, since none occurs without a passion from the body. Which implies: either no part of the soul is separable, or not. Something of the soul is separable from the body in relation to being, which we call intelligence (mens). Hence it is clear that intelligence (mens) is what is impassible wherein the three faculties cited above are located, insofar as they are impassible (esse quod impassibile in quo sunt memorata tria eo, quod impassibilia sunt). I say that the soul is to intelligence (mens) what the body is to matter (hyle): if the body and passive matter (hyle passiva) exist, then likewise the soul and passive intelligence (mens passiva) exist. But I say that intelligence (mens) is one, whereas souls are many, and matter is one, whereas bodies are many. Given that only the passions, that is accidents or properties, create differentiation among things, it follows that what is not subject to any passion would necessarily be one, which is the case for intelligence (mens) and matter. Things that are passive are necessarily many, and the properties in them necessarily make them different from one another (as is the case with bodies and souls). It is manifest that intelligence (mens) is one, as is matter. It must be asked whether intelligence (mens) and matter are a single thing or if they are different. Given that only passive things are different from one another, one sees that intelligence (mens) and matter do not differ at all, neither of them being subject to passions. But inversely, just as the passive intellect (passivus intellectus) that is in the soul only comprehends the body, similarly the impassible intellect (impassibilis intellectus), which is in intelligence (mens), only comprehends matter. It is also clear that the passive intellect (that is to say, the imagination) (passivus intellectus (hoc est ymaginacio)) only comprehends being, unless through assimilation to the sensed thing, since that exceeds nature. By analogy (per simile), one sees that the [im]passible intellect ([im]passibilis intellectus) can only comprehend matter if it has a similarity to it or if it is identical to it. It cannot be similar to it, since there is only similarity between passive things that are subject to the same passion, as is the case of two white things or two black things. One can deduce from this that intelligence (mens) and matter are identical. One sees that Plato agrees with this when he says that the world is a sensible God (mundum esse Deum sensibilem). For the intelligence (mens) that we are describing and that we are calling singular and impassible is none other than God. If the world is therefore God himself without his being accessible himself to sense (preter se ipsum perceptibile sensui), as Plato, Zeno, Socrates, and many others have said, then the matter of the world is God himself, and the form that comes to matter is none other than God making himself sensible (forma vero adveniens yle nil aliud quam id, quod facit Deus sensibile se ipsum). For quantity, as Aristotle says, is what happens first to matter and produces the body; what is happening to the body is the natural movement that produces the element. Though matter [may] seem impassible and immobile by virtue of its proper nature (vi sui nature), sense, however, receives the grandeur and the movement [that are] in it (in ea). It is therefore manifest that there is only one single substance, not only of all bodies, but also of all souls, and this substance is none other than God himself. And the substance of which all bodies is made is called matter, the substance of which all souls are made is called reason or intelligence (dicitur racio sive mens). It is therefore manifest that God is the reason for all souls and the matter of all bodies.
6The passage concludes a development of ten pages devoted to Aristotelian psychology (essentially to the senses, to the imagination, and to the affections), inspired by De Anima and Parva Naturalia. David proceeds from the question of the Treatise on the Soul: is there a faculty of the soul independent (or separable) from the body (see De Anima, I, 1 403a3-b19)? Evidently at issue is the central question on which the commentaries of chapters 4 and 5 of book III are divided, which are devoted to intellection. In David’s manuscript, the question radically transforms the tenor of the exposition, since we proceed from a “physiological” consideration of the operations of the soul to the definition of a mens that is impassible and separable from the body, the sole substance of particular souls, thereby arriving at the so-called “pantheist and materialist” thesis on the unicity of substance. In this sense, one can conjecture that David proposes to pass from the “naturalist” point of view that, according to Aristotle, “is concerned with all [the attributes] which are functions or attributes of such and such a body or matter,” to the point of view of the “first philosopher,” who is concerned with “[things] insofar as they are separate.”  The challenge of this text is evidently determining what meaning to give to this formulation.
7Methodologically, these three stages constitute a “resolution” that proceeds from accidents or properties to the definition of two principle-related subjects (matter and intellect), then from these two subjects to the definition of their substantive identity. To consider this approach, one notices that David, evidently a “subtle dialectician,” is no stranger to analogical thought in general, but in the sense that he understands Aristotle as a “naturalist” interpreter of the Platonic dialectic, that is, in the sense that, according to him, inference ascending from principle could only be that of a substantial subject. In other words, the participation of the multiple in the one must be comprehended as the relation of accidents to substance. Evidently, it is this thesis that seemed scandalous to the University of Paris’s theologians who, against such an interpretation, almost immediately saw how they could benefit (with Avicenna) from the celebrated definition of essence (to ti en enai) from book Z of Metaphysics and from a doctrine of substantial forms. The history of this assimilation is rather well known. The figure of David evidently opens onto another tradition, whose trace can undoubtedly be followed all the way to the Renaissance.
The Physiology of the Faculties of the Soul
8The text begins with a tripartite division of the faculties of the soul: there is “science, intellect, and will.” This series echoes the division found at the very beginning of the Treatise on Nature (Tractatus naturalis) where David writes: “There are three [faculties] in the soul: sense, imagination, and desire (Tria sunt in anima: sensus, ymaginacio, desiderium)” (Dinant 65). The terminological difference is immediately explained: one encounters two types of denomination that are distinguished according to whether the faculty is considered “passive” or “impassible.” “Sense” is a “passive science,” the “imagination” is a “passive intellect,” and “desire” is a “passive will.” The terms of the series are identical; only the point of view differs. There is on the one hand a “naturalist” or “physiological” definition, and on the other a definition of the same faculties insofar as they are “impassible.” The nature of this new point of view remains to be determined: it is the object of the fragment cited. Before continuing, one can already conjecture that this new point of view seems to correspond to the perspective proper to the “philosopher in the first sense,” described by Aristotle at the beginning of the Treatise on the Soul in a rather enigmatic manner as envisioning the affections as “separated.”
9David begins by rapidly summarizing the definitions of sense, imagination, and affection that he has just given.
10a) “Sense perceives nothing other than the passion produced (que fit) in the instrument of sense by the sensed thing.” A little earlier in the document, David had defined sense as “the soul’s perception of things that produce a passion in the body” (Sensus est percepcio anime earum que in corpore fiunt passiones) (Dinant 65; see Dinant 34). David therefore reprises the Aristotelian definition that makes sensation out to be the effect of an alteration of the organ by the sensible. What the soul perceives is therefore an alteration of the instrument on which is imprinted the trace of the perceptible thing. David calls the process “assimilation” in the sense that this trace, or imprint, constitutes a formal similarity of the sensible thing, which Aristotle calls “the sensible object but without the matter of that object.”  It is this affection that the soul therefore perceives when one says that it “feels.” David repeats it constantly: in sensation, “the soul only undergoes passions from the organs (anima enim solum patitur passiones ergo membrorum vel existentes in membris)” (Dinant 86). The study of sensation is therefore derived from physiology, that is, from the study of the organ and its propensity to be altered by sensible objects.
11b) Hence one comprehends the definition of the imagination: “The imagination is produced (fieri) . . . based on a preexisting sensation, [it] perceives nothing other than the sign or the trace (signum uel uestigium) of a sensible passion.” The imagination is also the object of a physiology. Following Aristotle’s treatises on memory and on dreams, David explains imagination and memory by the persistence of the alteration of organs. Just as sensation is “the perception of a passion occurring in the sense organ under the effect of the sensed thing,” likewise the imagination is “the perception of a passion that remains in the senses after the disappearance of the perceptible thing” or even “the sign or the trace of preexisting passion (signum vel vestigium preexistentis passionis)” (Dinant 67; see Dinant 35). The imagination, from a physiological point of view, constitutes a power identical to sense: in both cases, there is a perception of an organic alteration—whether the sensible object is present or not changes nothing about the process.
12This physiological study must evidently be articulated to a psychology that must account for the “perception,” proper to the soul, of organic alterations. This is how David suggests giving a new, “psychological,” (no longer physiological) meaning to the imagination to designate the “perception” of the soul (and no longer the alteration of the organ). Thus, David says, to explain how the sensible objects appear distant from the organs, that the corporal passions are perceived fantastice, that is to say, in the representative mode: “We say that the soul only perceives the color that is in the eye and that color appears fantastice, distant from the eye” (Dinant 87). In other terms, imagination performs an abstraction from the sensible form imprinted in the organ and thereby produces a representative “image” (imago) (Dinant 87). This is how David comprehends the Aristotelian formulation that connects our knowledge back to the imagination: “There is no intellection without image (Non est intelligere sine fantasmate),” that is, “all our knowledge proceeds from the imagination and does not take place without image.” 
13The originality of the commentary derives from encountering a noetics that erases the traditional partition between sensible knowledge and intellectual knowledge.  David insists upon the fact that, in Aristotle’s work, imagination and sense constitute the same faculty or power of the soul (“Dicit autem Aristoteles quodam in loco: ymaginationem quodammodo esse sensum et eandem vim anime esse ymaginationem, quam et sensum”)  (Dinant 67). The operation of abstraction proper to the intellect does not therefore consist in passing from a sensible knowing to an “intellectual” knowing; it belongs to all knowledge. It accounts for the passage from organic alteration, object of the physiology of book II of the Treatise on the Soul, to the constitution of the image or the sign in the soul, which is, properly speaking, the objective of noetics.
14c) The case of desire is similar: “Affection is produced in the soul by the alteration (nisi per immutaciones) of the systoles and diastoles, through heating or cooling of the blood or of the spirit that is in the heart.” The physiological cause of affection, the passion of the heart, engenders a passion of the soul: “And all affection is produced from a passion of the heart and, without a passion of the heart, no affection can occur in the soul (Omnis autem affectus fit ex passio cordis; nec sine compassione cordis potest fieri affectus in anima)” (Dinant 67). If the passion of the heart and the affection of the soul are contemporaneous, the causative order does not, however, cause David any doubt: “Manifestum est igitur, quod licet passio cordis et affectus anime simul tempore fiant, passio tamen cordis causa est affectionis, que <fit> in anima”  (Dinant 67).
The Status of the Passive Intellect
15How does one pass from these passive faculties of the soul to the definition of impassible faculties? Certainly not by studying a cognitive process specifically separate or independent from the body. David clearly refuses the traditional route that superposes an intellectual knowledge onto knowledge of sensible objects. Knowledge of the universal does not proceed from a distinct faculty of the imagination. According to David, this is what Aristotle means when he “proves,” against Plato, that “ideas absolutely do not exist” (ideas omnino non esse). Contra Plato, for whom “the imagination perceives ideas and [for whom] ideas are the imaginary forms of bodies,”  it must be repeated that the imagination only perceives the alteration of the organ. The idea or the imaginary form is none other than the image in the soul of bodily passion. Said another way, when Aristotle writes that the “forms” or “ideas” “do not exist,” that means, for David, that the forms are only the passions or accidents of a subject. What this therefore means is that the discourse only becomes concrete with the definition of the (physical or psychological) subject.
16In such a context, the object of chapters 4 and 5 of book III of the Treatise on the Soul is not to define a new faculty of the soul. This object, rather, is metaphysical, in a sense, moreover, that is rather indeterminate: after outlining the genesis and nature of imaginary forms, and once the specificity of the imagination has been defined, Aristotle, according to David, moves on to studying the subject-receptacle-of-forms. This is what leads David to identify the patient intellect of the imagination and to interpret chapters 4 and 5 of book III of De Anima as a development on the idea that the soul, in its intellective portion, is “the place of ideas”(topos eidon). For David, this place becomes the locus ymaginationis, identified above moreover with the locus memoriae, in which images of past sensations are found. To back up this critique of Plato’s “ideas,” David goes on to identify memory and imagination: “Dicit etiam memoriam idem esse, quod ymaginationem, nam memoriam efficit remanencia fantasmatum in loco ymaginationis. Rememoracio vero est inuestigacio fantasmatum in loco memorie” (Dinant 67). In other words, the forms or ideas are not the objects of an “imagination” independent of sensation: they are only the “signs” or the “traces” of a preexisting passion. This clearly signifies that, as for the operation, no faculty of the soul is independent of organic powers. The thesis, if not its formulation, is perfectly common: it lends credence to Albertus Magnus, who held that David was a “disciple of Alexander.”
17What is perhaps more unusual, however, is that the definition of the patient intellect as subject that potentially contains intelligible objects corresponds here to the definition of the soul as noetic subject. Just as the organic body is subject to passions provoked by the sensible objects, likewise the imagination can be thought of as the subject of ideas that are the images or signs of organic alterations. This is how David comprehends Aristotle’s comparison: the intelligible object is to the potential intellect what the sensible object is to the faculty of sense  (faculty identified above by David with the corporal organ). The comparison therefore puts in parallel, for David, not two types of knowledge, but a physiological and a psychological process: the passivity of the organ is analogous to that of the intellect, substrate or “locations” of the idea or of the imaginary form.
18The inference of the patient intellect from book III of De Anima is consequently similar to that of the substrate of becoming at the end of the first book of Physics (I, 7). In both cases, it is a matter of connecting a change or a process, the acquisition of a form or of a disposition, back to the permanent subject of the change. In the text, the inference of the intellective subject is assumed as far as the soul is concerned. Several times, David makes reference to the patient intellect, which he also calls mens passiva, by putting it in parallel with the body or yle passiva, physical subject of alteration. Still remaining, however, is to proceed to the inference of the mens properly speaking.
The Invention of the “Mens”
19The invention of the mens proceeds via analogy as well:
I say that the soul is to intelligence (mens) what the body is to matter (hyle): if the body and passive matter (hyle passiva) therefore exist, then likewise the soul and passive intelligence (mens passiva) exist. But I say that intelligence (mens) is one, while souls are many, and matter is one, whereas bodies are many. Given that only the passions, that is to say accidents or properties, create differentiation among things, it is necessarily so that what is not subject to any passion is one, which is the case of intelligence (mens) and of matter (yle). 
21We can summarize his argument thus:
221) The body itself is known or inferred from passions or sensible alterations that affect it. This inference therefore lets us know the body as the passive substrate (hyle passiva) of these affections. Similarly, the mens passiva, or patient intellect, is inferred from sentiments, that is, from the imaginary forms of which it is the receptacle.
232) Just as the unity of matter can be inferred from the multiplicity of bodies, likewise the unicity of the mens, subject of all souls, must be inferred from the multiplicity of psychological subjects.
24These lines must evidently be read as a paraphrase, and a remarkable one at that, of the beginning of chapter 5 of book ? of De Anima:
Since in each genus of things there is something, e.g. matter, as in every case of [things by] nature (and matter is that which is potentially each of these things), and also something else which, by producing those things, is the cause and is capable of acting, as in the case of art in relation to its material, these different [principles] must belong to the soul also. And one [principle] is an intellect of the sort that can become all things, but the other is such that, like a sort of disposition, it can make all things, as in the case of light; for in a certain sense light, too, makes potential colors be actual colors. And the latter intellect is separable and cannot be affected by or be blended with anything, and in substance it exists as an actuality; for that which acts is always more honorable than that which is acted upon, and the principle [of a thing which has matter is always more honorable] than the matter [of that thing]. 
26The difficulty is understanding how David can interpret Aristotle’s text this way. The text of De Anima puts two principles on display, a “material” principle, and a principle that serves as an “efficient cause.” It explains the production of intellection via a double analogy, one artisanal, the other optical: the intellect is called “agent” in the sense that it is analogous to the producer and to light. In one case, as in the other, with its function being to actualize objects that only exist in force in a subject, it should be called transitive cause. And, for David, this agent is immanent cause. It is therefore evidently not by following the artisanal metaphor that one will comprehend the Quaternuli’s interpretation. Rather, it is the optical analogy that must be followed. It alone allows us to account for the substantial identity of the patient and of the agent, and of the immanence of the soul to the universal mens.
27In the preceding sections, David developed a physiology of vision that began with this extremely dense formula, which is supposed to summarize the thesis of De Anima II, 7: “I say that sight perceives nothing other than the passion of the eye, that is, the color, insofar as it is altered by the thing seen through the mediation of the air, which is apt to act and to undergo (Dico autem, quod uisus nichil aliud percipit quam passionem oculi, hoc est colorem, secundum <quem> alteratur a re visa per medium aerem, qui aptus est agere vel pati)” (Dinant 65). The physiological process of vision in Aristotle’s work is indeed a three-term relation. It puts in play not only the eye and the sensible object, but also the air or, in general, the diaphanous environment. What alters the organ is never the colored thing itself, but always the environment. The role of this diaphanous environment is not therefore limited to assuring the link between the visible and the organ, it is not only the vehicle of perceptible species; it is its efficient cause as well. It is in the diaphanous environment, prior to the alteration of the organ, that the process of abstraction or assimilation takes place that renders the colored object visible. If the diaphanous environment is “passive,” it is set in motion by the bodies from which it receives light and color. This physical process can be decomposed by saying that light actualizes the diaphanous environment and prepares it for the reception of color: without light, the transparent environment is effectively not susceptible to being informed by the color of opaque objects. And yet, David refuses to grant light a special status (as is done for example by one Grosseteste). Light is only a color among others, and, in this respect, it is an accident of the air: “lux non est corpus, sed accidens corporis, id est ipsum aeris. . . . Dico ergo, quod lux nichil est aliud quam color, secundum quem diafanum corpus alteratur a lucido corpore assimilante illud sibi secundum suum colorem. Nam quemadmodum ignis calefacit aerem, ita et colorat eum colore suo. Color autem, secundum quem alteratur aer ab igne, dicitur lux” (Dinant 65). Here we thus find the thesis that characterizes David’s “radical” Aristotelianism: actualization is always the effect of an alteration and formal perfection, a passion of the subject. It is never thought of in the manner of the real composition.
28The diaphanous element is therefore active in the sense that it communicates its movement to the instrument of vision. Colors are only imprinted on the eye by way of the environment to which the function of abstracting or assimilating the color of bodies belongs. The eye therefore only sees a color made visible beforehand by the diaphanous environment, and it is through contact with the air that the transmission of the motion is realized:
Et dico, quod lux est albedo, que disgregat; et lux est color ymaginaliter generatus a colore corporis lucidi in corpore dyaphano. Dyaphanum vero corpus est, in quo alia corpora depingunt proprios colores, ut aer et aqua et multa alia solida. Unde Aristoteles: Color quidem movet dyaphanum, diaphanum vero aerem et ab illo continuo existente movetur instrumentum visus. Cum enim videmus, res visa movet coniunctum sibi aerem secundum colorem sibi similem et ille < > quod aer, qui coniunctus est oculo, verum colorem recipit simile, quod in oculo depingit. Item omnis color motivus et alterativus est corporis actu dyaphani, <actus autem dyaphani lux est>; et hec est causa, propter quam non est visibile sine luce. Lucidum vero corpus est quod natum est actione sua colorare dyaphanum corpus secundum colorem similem sibi (David 85).
30What the eye sees are therefore not visible exterior bodies immediately, but the colors that these bodies have imprinted on the diaphanous environment. Vision is only possible if, beforehand, the air has assimilated the colors of visible things. Hence, strictly speaking, it is not the organ that effects the first abstraction from form, but the diaphanous environment. The eye only sees by “conjunction” with that universal subject of images that is the diaphanous environment.  And this conjunction is possible because the organ and the environment are alike in nature.
31In light of this theory of vision, the interpretation of chapters 4 and 5 devoted to the intellect is better understood. The patient intellect, that is to say the locus ymaginationis, psychological subject of imaginary forms, is analogous to the eye that receives color. This passive subject would receive no form without an agent, that is, without a mens which performs the abstraction and the assimilation of the intelligible object, just as active, or rather, illuminated transparency, assimilates colors by transforming the quality of the sensible body into visible color. If the agent intellect must be distinguished from the passive or potential intellect, this in no ways means that they differ as two substances, but, as in the case of the difference between the eye and the diaphanous environment, as whole and part. Just as the eye, a bodily organ, only receives colors because it is a part of the medium, likewise the mens passiva, or soul, only thinks, imagines, or even perceives the movements of the body to the extent that it is a part, associated with an organic body, of the impassible mens.
32Hence, we glimpse the principles that found this interpretation of Aristotle, which is undoubtedly slightly unusual in view of our philology. Efficient and formal causality supposes the identity of the immanent subject. If the form qua form is only an alteration or a passion of the subject, it must be deduced that it would not be in a position to be a transitive cause of its effect, unless abstractly. Precisely because David’s inference supposes, on the contrary, this rather speculatively strong thesis: the efficient cause is always immanent. All production supposes a medium. Ex nihilo nihil.
The Identity of “Hyle” and “Mens”
33David is perfectly clear: the form, principle of difference, is an affection of the substrate. The definition is not “dialectical,” in the sense that David would be conflating the logical composition (of kind and of difference) with physical composition (of matter and of form), the logical difference and ontological diversity, as Thomas Aquinas would reproach him for doing.  If, for Thomas, difference is abstract and diversity real, it is in the sense that this is, in created things, the index of absolute difference that exists between the divine act and the privation of being. For David, it is on the contrary difference that is real or “physical.” Diversity is only an abstract difference. Thinking diversity as primary consequently comes back to depriving the substrate of all ontological dignity and, in the end, regressing, below Aristotle in the direction of that “Platonism” which disallows all rational knowledge of movement unless it distinguishes matter from the lack of matter, by separating the forms of the subject of which they are immanent determinations (see Physics, I, 9, and II, 2). Going a bit further, one will say that it also means taking at face value a “logical” definition of substance as subject of predication or even as “this determinate [ceci déterminé]” (Categories, 2 and Metaphysics, Z, 3). The point of view of form is ultimately still abstract and imaginary: it is adequate for the grammarian, and sometimes for the naturalist, but not for the philosopher.
34This is the reason why David always draws the conclusion, in the texts that have come down to us, from formal similarity to substantial identity. It is understandable, then, how he next identifies matter with intelligence: matter without form would not be in a position to be apprehended by similarity, that is to say by means of an accident or of a form (“the [im]passible intellect can only comprehend matter if it has a certain similarity with it or if it is identical to it. And it could not be similar to it, since there is only similarity between passive things, subject to the same passion”). In other words, the imagination, insofar as it perceives an alteration of the body, would not know how to comprehend prime matter without form. If therefore one says that intelligence thinks matter, this must be in a nonimaginative, purely intellective mode. It is only at this point that David is led to distinguish two modes of knowledge: when it is about defining the self-intellection of the first principle that cannot be thought imaginatively due to its impassible and therefore formless character. Hence, the thesis of the identity of the intellect agent and of the intelligible come to found the identity of the mens with the prime material, which constitute one, single substance. And David naturally chooses to call this single substance “God.” The divine production, consequently, has nothing of a demiurgical or artisanal production about it. God does not produce distinct substantial realities from himself. The sensible effect of absolute power must rather be comprehended as an immanent production whose effect does not emerge from its cause. Hence the slightly enigmatic formulas by which David interprets the definition, presented as traditional, of the “world” as “sensible God.” The text that we still have is evidently much too allusive for one to go much further. Besides that, it is not said that David himself considered it possible or necessary to undertake a causal demonstration of the multiple.
35This dense and problematic text gives a singular glimpse into what could have been the entrance of Aristotle’s “natural philosophy” into the University of Paris. The documents at his disposal remain fragmentary, however, and it appears difficult to offer something other than conjectures. Ours was the following: we encounter, with David of Dinant, a reading of Aristotle’s natural philosophy which aims to confront, in the framework of an interpretation of De Anima, the delicate question of the articulation of the naturalist point of view to the point of view of first philosophy. With the Problemata as well as natural and biological treatises as its points of departure, Aristotle’s first philosophy had to be understood as based on the reform of the Platonic dialectic. The resolution that leads to first principles is not to be sought in a theology of formal cause; it passes to the contrary by way of the invention of the subject of becoming, as Aristotle sketches it at the beginning of Physics when he vigorously distinguishes matter from privation. Evidently, this perspective suggested by this fragment of the Quaternuli remains to be justified. Interest must go “upstream,” to David’s sources, that is to say to Aristotle’s texts and to the Greek commentators (in particular to Alexander) that he must have had in his hands, as well as to the (undoubtedly medical) tradition to which he indeed seems linked. An attempt must also be made at justifying these conclusions from the starting point of the debates around Aristotelianism and around the interpretation of Alexander of Aphrodisias, with which (rather appropriately, as we have seen) the name of David is often associated. Before Albertus Magnus, it is undoubtedly in the extremely violent polemic of William of Auvergne against the Greek exegete that one finds some elements of a response. “Downstream,” the wide diffusion of Aristotle and Averroes’s commentaries certainly quickly led to the Quaternuli’s going out of fashion, the Quaternuli whose aim was making a “new” natural philosophy available: Aristotle’s philosophy. That does not mean, though, that David’s suggestions remain a dead letter—quite the contrary.
The decree of 1210 targets Amalric of Bena as well, but David’s writings are the more direct occasion for condemning Aristotle’s “natural books.” The decree targets Aristotle in these terms: “On pain of excommunication, no one in Paris may read Aristotle’s books on natural philosophy or their commentaries, whether publicly or privately” (nec libri Aristotelis de naturali philosophia nec commenta legantur Parisius publice vel secreto, et hoc sub pena excommunicationis inhebimus). Cited in L. Bianchi, Censure et liberté intellectuelle à l’université de Paris (XIIIe - XIVe siècles) (Paris: Les Belles Lettres, 1999), 92. The works targeted are those translated and presented in David’s Quaternuli: Aristotle’s biological, psychological, physical, and metaphysical works. The decree targets neither the possession, nor the study, nor even the use of these books, but forbids them to be considered as a specific object for (public or private) lessons. In 1231, Gregory IX’s bull Parens scientiarum confirms the ban while waiting for Aristotle’s works to be “examined, and expurgated of every suspicion of error.” (see L. Bianchi 104). On David of Dinant, see G. Théry, Autour du décret de 1210: I.—David de Dinant. Étude de son panthéisme, (Le Saulchoir, France: Kain, 1925); M. Kurdzialek, “David von Dinant als Ausleger der aristotelischen Naturphilosophie,” in Die Auseinandersetzungen an der Pariser Universität in XIIIe Jahrhunders, ed. A. Zimmerman (Köln, Germany: De Gruyter, 1976), 181–192; E. Maccagnolo, “David of Dinant and the Beginnings of Aristotelicianism in Paris,” in A History of Twelfth Century Western Philosophy, ed. P. Dronke (Cambridge: Cambridge University Press, 1988), 429–442; M. Th. D’Alverny, “Les nouveaux rapports dans le domaine de la science et de la pensée au temps de Philippe Auguste,” in La France de Philippe Auguste: le temps des mutations, ed. R. H. Bauthier (Paris: Éditions du Centre national de la recherche scientifique, 1989), 863–880; Elena Casadei, “David di Dinant, traduttore di Aristotele, Freiburger Zeitschrift für Philosophie und Theologie 45 (1998): 381–406; and “Il corpus dei testi attributibili a David di Dinant,” Freiburger Zeitschrift für Philosophie und Theologie 48 (2001): 87–124.
Théry, Autour du décret, 38–39.
David de Dinant, Quaternulorum fragmenta, ed. M. Kurdzialek (Warsaw: Pan?stwowe Wydawnictwo Naukowe, 1963). See A. Birkenmajer, “Découverte de fragments manuscrits de David de Dinant,” Revue Néoscolastique de Philosophie 35 (1933): 220–229.
Here is how the Ghent and Oxford manuscripts begin, by evoking the “discovery” of the Problemata: “Cum essem in Grecia, peruenit ad manus meas liber aristotelicus De dubitabilibus problematibus in unaquaque arte” (Ghent manuscript, Dinant 3); “Cum essem in Grecia, peruenit ad manus meas liber Aristotelicus quidam, cuius inscripcio erat de diversis unius cuiusque metodi problematibus.” (Oxford manuscript, Dinant 91)
Elena Casadei’s recent works (cf. “David di Dinant, traduttore di Aristotele”) have shown that David is effectively a doctor.
For a snapshot of this perplexed reception, see “Melancholy in Medieval Medicine, Science, and Philosophy,” in Saturn and Melancholy: Studies in the History of Natural Philosophy, Religion, and Art, ed. R. Kilbansky et al. (Nendeln, Liechtenstein: Kraus Reprint, 1964/1979), 67–112, and in particular the pages devoted to Albertus Magnus, Alexander Neckham, and William of Auvergne (67–77). [“La mélancolie dans la médecine, la science et la philosophie du Moyen Âge,” in Saturne et la mélancolie Études historiques et philosophiques: nature, religion, médecine et art, trans. Fabienne Durand-Bogaert and Louis Évrard (Paris: Gallimard, 1989), 123–197 and in particular the pages devoted to Albertus Magnus (124 and 126–127), to Alexander Neckham (125), and to William of Auvergne (130–131)].
Cited in Théry, Autour du décret, note 1. He furnishes numerous occurrences where Albertus evokes David’s Libri Alexandri: in light of the edited fragments, it is highly probable that David may have also translated or commented on some works or fragments by Alexander. In addition, the extreme virulence of William of Auvergne against Alexander’s psychology in his De Anima (essentially in chap. V) would tend to prove that his basic adversary at the University of Paris is not Avicenna’s “Neo-Platonic Aristotelianism” as much as it is the exegete’s inspired “materialism.” On the diffusion of Alexandrianism in the Latin world, see the conjectures by Théry, Autour du décret.
Dinant. Quaternuli Fragment, 69–71: the editor entitled it Mens, hyle, Deus. The text is elliptical and one can suppose that this trait is accentuated by the copyist who summarizes to the extreme the author’s argumentation—the impression is confirmed if one compares this passage with the one, even more elliptical, from the Vienna manuscript (the W fragment) that corresponds to it: Quaternuli Fragment, 88. The commentary that is offered about it here is an attempt at reconstituting it. It is useless to add that the limits and dangers of such an approach have not escaped us.
We read impassibilis where M. Kurdzialek gives passibilis. The correction is obvious given the context.
Aristotle. On the Soul, A, 1, 403b9-17, trans. Hippocrates G. Apostle (Grinnell, IA: The Peripatetic Press, 1981), 3–4.
11Aristotle, On the Soul, ?, 2, 425b22-25, trans. Apostle, 43-44. “Further, that which sees, too, is in a certain sense colored; for each sense organ is receptive of its sensible object but without the matter of that object. It is in view of this that sensations and imaginings of those objects exist in the sense organs even when those objects are gone.”
“Ex hoc patet omnem cognicionem anime fieri ymaginacione <et> non sine fansmate. Unde dicit: Non est sine fantamate” (Quaternuli Fragment, 87). Elsewhere, David cites Aristotle’s formulation, in analogous contexts, but it consists first and foremost of a lexical remark on the Greek phantasia and its derivatives: see Quaternuli Fragment, 35 and 67 (“Id ipsum autem fantasiam uocat, ubi ait: Non est intelligere sine fantasmate”). The formulation, as we know, recurs throughout Aristotle’s work: see, for example, Aristotle, On the Soul A, 1, 403a 8–10 and ?, 7, 431a 16–17; Aristotle, On Memory, 1,449b 30–450a 5.
But without annulling it: “Duplex est cognicio: sensitiva, qua singula congnoscimus, et racionativa, qua universale scimus” (Dinant 87) This knowledge of the universal is “rational,” in other words, discursive, and does not consequently suppose any faculty other than the imagination.
But also, Quaternuli Fragment, 34: “Dico autem, quod sensus et ymaginatio fiunt in eisdem partibus corporis, idest in ipsis sensuum instrumentis.” See Aristotle, De la mémoire, 1,449b 31–450a, trans. R. Mugnier (Paris: Les Belles Lettres, 1965), 54: “The imagination is an affection of common sense. Evidently it follows that the knowledge of these ideas belongs to the principle of sensitivity” [back-translated from the French].
See also Quaternuli Fragment, 36–39. This physiology of the passions (inspired by Galenism) could be deepened by evoking the translations of Problem XXX, 1 on melancholy and Parva Naturalia, which open the Ghent manuscript.
“Visum est autem Platoni ymaginationem esse perceptivam ydearum et ydeas esse ymaginarias corporum formas.” (Quaternuli Fragment, 67, but also 35). David’s editor connects this presentation of Plato to Plutarch (“Socrates et Plato Ideas putaverunt a materia secerni et in intellectu atque imaginatione Dei subsistere”), which is evidently not the only possible source.
Aristotle, On the Soul, ?, 4: “If thinking is indeed like sensing, then it would either be a process of being affected in some way by the object of thought or be some other thing such as this. So [the thinking part of the soul] should be incapable of being affected by capable of receiving the form [of the object of thought] and be potentially such as that [form] but not the [form] itself; and the intellect should be related to the object of thought in a manner similar to that in which a sense is related to its sensible object” (trans. Apostle, 49).
See this analogous text, although it is even more elliptical: Quaternuli Fragment, 88 (“Et si yle est corpus passivum, <ita> et nois et anima passiva. Hyle est omnia corpora per adventu formarum et nois omnes anime. Item quecumque differunt, formis differunt. Ergo si non formis differunt, non differunt, ergo idem sunt. Et ita voluerunt philosophorum Plato et alii, quod mundus iste est deus prebens sibi visibile et est yle corporum et mens animarum/ Unde Juppiter quodcumque vides. Primo advenit yle quantitas et factum est corpus, postea motus est gl’a [: elementa]”)
Aristotle, Of the Soul, 430a 10 ff, trans. Apostle, 51.
To grasp the meaning of this process, one can refer to this formulation by Leonardo da Vinci: “The atmosphere, in its entirety and in all its parts, is full of images of the bodies that it contains,” Carnets, ed. E. Maccurdy, trans. L. Servicen, (Paris: 1942), 243 [back-translated from the French]). The thesis is not new and it is quite common, even. One can moreover note that the “scandalous” thesis by Averroes (the one about the unity of the passive intellect) surely stems in part from the fact that he took the visual analogy from De anima III, 5 seriously: just as the eye only sees images of things in conjunction with the transparency that is “universal” or common to all, similarly the speculative intellect only grasps intelligible objects in conjunction with the universal intellect that is possible and single in number. When, against Averroes, Thomas Aquinas invents the fiction of the eye for all who see (L’Unité de l’intellect contre les averroïstes, § 85, trans. A. de Libera, (Paris: Garnier Flammarion, 1994), 161), the situation that he imagines is probably not in reality very far from the one that is described in the pages of De Anima devoted to the diaphanous environment. Evidently, to the extent that he does not distinguish two kinds of knowledge, but two effects (one physiological, and the other psychological), David does not at all posit the unity of the patient intellect that he identifies with the imagination: his psychology is clearly inspired by Alexander.
Thomas Aquinas, Somme contre les Gentils, I, 17, (Paris: Éd. du Cerf, 1993), 45 (French translation). [Summa contra gentiles. trans. Anton Pegis. (New York: Random House, 1945), 38–39.] “The ravings of David of Dinant are hereby confounded, who dared to assert that God is the same as primary matter, because if they were not the same, they would needs differ by certain differences, and thus they would not be simple: since in that which differs from another thing by a difference, the very difference argues composition. Now this proceeded from his ignorance of the distinction between difference and diversity. For as laid down in Book 10 of the Metaphysics, a thing is said to be different in relation to something, because whatever is different, differs by something, whereas things are said to be diverse absolutely from the fact that they are not the same thing. Accordingly we must seek for a difference in things which have something in common for we have to point to something in them whereby they differ: thus two species have a common genus, wherefore they must needs be distinguished by differences. But in those things which have nothing in common, we have not to seek in what they differ, for they are diverse by themselves. For thus are opposite differences distinguished from one another, because they do not participate in a genus as a part of their essence: and consequently we must not ask in what they differ, for they are diversified by their very selves. Thus too, God and primary matter are distinguished, since, the one being pure act and the other pure potentiality, they have nothing in common.”