Two Models of Thinking - Fordham University Faculty

Two Models of Thinking:Thomas Aquinas and John Duns ScotusGiorgio PiniSuppose I am thinking about what it is to be a cat. What sort ofactivity am I engaging in? What is it to think about something? ThomasAquinas and John Duns Scotus answered this question in two remarkablydifferent ways. Even though Scotus did not develop his theory of thinking indirect opposition to Aquinas, a comparison between their treatments will helpus focus on their distinctive strategies to deal with what they called “acts ofthinking.” 1It will be convenient to break down the question “what is it to thinkabout something?” into the following three questions:(1) What sort of thing is an act of thinking?(2) What are the necessary and sufficient conditions for an act ofthinking to occur?(3) What accounts for an act of thinking’s being about something?And specifically, what accounts for a certain act of thinking’s being about acertain thing as opposed to another, say about what it is to be a cat rather thanwhat it is to be a dog? 2These questions are clearly distinct. The first question concerns theontological status of an act of thinking. By contrast, the second question bearson the mechanisms of cognition. Finally, the third question concerns theintentionality of an act of thinking. It is a typical trait of later medieval theoriesof intellectual cognition to regard these three questions as closely connected.1 By “act of thinking,” I translate the following Latin expressions: actus intelligendi,actus cognoscendi, actualis cognitio, intellectio, notitia, notitia actualis, notitia actualis genita inintellectu. Both acts of thinking and their contents were being referred to as “concepts”(conceptus). Scotus called attention to this equivocal usage of the term “concept” in hisTheoremata, pars 3, def. 1, n. 1, OPh II, 609. Sometimes, the technical notion of intelligiblespecies was also referred to as a concept. All these items (i.e. acts of thinking, their contents, andintelligible species) are to some extent mental entities and, accordingly, concepts. But they shouldbe carefully distinguished from one another if any sense is to be made of later medieval theoriesof intellectual cognition. In order to avoid any confusion, I refrain from using the term “concept”as much as possible. When I do introduce that term (e.g. in order to refer to the product of an actof thinking in Aquinas’s second account of thinking), I will specify what sort of entity I take theterm “concept” to refer to.2 On the distinction between the general and the specific problem of intentionality, seeJ. E. Brower and S. Brower-Toland, “Aquinas on Mental Representation: Concept andIntentionality,” The Philosophical Review 117 (2008): 193–243, at 194.1

Specifically, the answer given to the first question was supposed to have abearing on the answers given to the other two questions.Interpreters of later medieval philosophy have recently devoted muchattention to the second and especially the third question, i.e. to the issue ofthe mechanisms of intellectual cognition and thought’s intentionality. Inparticular, much effort has been recently spent to investigate medievaltheories of mental representation. 3In comparison, the question regarding the ontological status of an actof thinking has attracted little attention. In this paper, it is my hope to showthat the contrast between Aquinas’s view that acts of thinking are actions andScotus’s alternative view that acts of thinking are mental qualities is muchmore than a negligible disagreement concerning an abstruse issue in cognitivepsychology. Rather, this difference should be regarded as a key point toevaluate those two thinkers’ respective accounts of thinking. 4I must make four provisos about the scope of this paper.First, my focus will be on human thinking. Accordingly, I will not takeinto account the way God and angels engage in thought.Second, my focus will be on simple acts of thinking or simplethoughts. It was a common view among later medieval thinkers that mythinking about cats counts as a simple act of thinking or “simpleapprehension” (simplex apprehensio). By such an act, I grasp what cats arebut I engage neither in predicating any property of cats nor in drawing any3 See R. Pasnau, Theories of Cognition in the Later Middle Ages (Cambridge: CambridgeUniversity Press, 1997), 31–124; D. Perler, Theorien der Intentionalität im Mittelalter (Frankfurtam Main: Kostermann, 2002); D. Perler, Théories de l’intentionnalité au moyen âge (Paris: Vrin,2003); J. P. O’Callaghan, Thomist Realism and the Linguistic Turn. Toward a More Perfect Form ofExistence (Notre Dame: University of Notre Dame Press, 2003); P. King, “RethinkingRepresentation in the Middle Ages: A Vade-Mecum to Medieval Theories of MentalRepresentation,” in Representation and Objects of Thoughts in Medieval Philosophy, ed. H.Lagerlund (Aldershot: Ashgate, 2007), 81–100; Brower and Brower-Toland, “Aquinas on MentalContent.”4 It is not my claim that Thomas Aquinas and Duns Scotus were the only supporters oftheir respective views. Because of the sophisticated treatments they devoted to this issue,however, they may be regarded as their two main proponents. Several thinkers seem to haveadopted the view that acts of thinking are actions, even though they rejected some or even mostof the other aspects of Aquinas’s account of intellectual cognition (e.g. James of Viterbo, Peter ofJohn Olivi, Thomas Wylton, and William of Ware). After Scotus, William Ockham was among thesupporters of the view that acts of thinking are mental qualities. See William Ockham,Quaestiones in tertium librum Sententiarum. Reportiatio, q. 7, OTh VI, 197–199; Panaccio,Ockham on Concepts, 21–23. By contrast, the Carmelite friar, Guido Terreni, who was familiarwith both Wylton’s version of the view that acts of thinking are actions and Scotus’s view that actsof thinking are qualities, adopted a mixed position, according to which an act of thinking hassome features of an action, some features of a passion, and some features of a quality. I wish tothank Cecilia Trifogli for letting me have a copy of the forthcoming paper, L. O. Nielsen and T.Trifogli, “Guido Terreni and His Debate with Thomas Wylton,” Documenti e studi sulla tradizionefilosofica medievale 20 (2009).2

conclusion about cats. Accordingly, simple acts of thinking should becontrasted both to acts of “composition and division” (compositio et divisio),i.e. propositional acts such as the act of thinking that cats are graceful or thatthey do not fly, and to acts of reasoning (ratiocinatio, argumentatio), such asthe act of thinking that, since cats are animals and animals need to eat, catsneed to eat. 5 Since it was commonly assumed that I can engage in predicatingand reasoning only if I have some grasp of the thing of which I am predicatingsome property or about which I am drawing some conclusion, an account ofsimple acts of thinking was regarded as a prerequisite to any attempt ofexplaining predication and reasoning.Third, my focus will be on what were called “abstractive” as opposedto “intuitive” acts of thinking. Thus, I will be dealing with acts of thinking suchas my thinking about what it is to be a cat, i.e. about the necessary andsufficient conditions that something must satisfy in order to count as a cat,independently of whether anything satisfies such conditions. I will not bedealing with acts of thinking to which it makes a difference whether theirobjects actually exist or not, such as my act of thinking about my currentdesire for a glass of milk. Whether I have or do not have a desire for a class ofmilk makes a difference with regard to the identity of my act of thinking aboutthat desire as my current desire. By contrast, an act of thinking about theessential features of cats would be the same even if cats were extinct. 6Fourth, my focus will be on general acts of thinking, such as thoughtsabout what it is to be a cat, as opposed to singular thoughts, such as thoughtsabout this or that individual cat. 7This paper is divided into three main parts. First, I present the mainelements of Aristotle’s account of what it is to think. Second, I turn toAquinas’s interpretation of Aristotle’s account. Third and finally, I considerScotus’s account of what it is to think.5 See for example Aquinas In Peryerm., I, 1, 1,5; In An. Post. I, 1, 2, 4–5; In IV Meta.,lect. 4, n. 574; In IV Meta., lect. 17, n. 736. See R. W. Schmidt, The Domain of Logic according toSaint Thomas Aquinas (The Hague: Nijhoff, 1966), 53–57; R. Pasnau, Thomas Aquinas on HumanNature. A Philosophical Study of Summa theologiae Ia 75–89 (Cambridge: Cambridge UniversityPress, 2002), 273; E. Stump, Aquinas (London and New York: Routledge, 2003), 265–266.Aristotle had distinguished two acts of the intellect in De anima III, 6, 430a26–b6.6 On the distinction between abstractive and intuitive cognition in Scotus, see S. J. Day,Intuitive Cognition. A Key to the Significance of the Later Scholastics (St. Bonaventure, NY:Franciscan Institute Publications, 1947), 39–139; K. H. Tachau, Vision and Certitude in the Age ofOckham. Optics, Epistemology and the Foundations of Semantics 1250–1345 (Leiden/NewYork/København/Köln: Brill, 1988), 68–75; S. D. Dumont, “The Scientific Character of Theologyand the Origin of Duns Scotus’ Distinction between Intuitive and Abstractive Cognition,”Speculum 64 (1989): 579–599; R. Pasnau, “Cognition,” in The Cambridge Companion to DunsScotus, ed. T. Williams (Cambridge; Cambridge University Press, 2003), 296–300.7 On singular thoughts in Scotus, see Peter King’s paper in this volume.3

1. Aristotle’s hylomorphic account of thinkingSince Aquinas’s account of thinking is a development of Aristotle’sviews on the same topic, it is necessary to start with a general outline ofAristotle’s treatment of what it is to think about something.Aristotle explained both perception and thought by applying to themhis hylomorphic analysis of change. According to Aristotle, in any change it ispossible to identify a subject or patient, which plays the role of matter, andtwo contrary states, i.e. the initial state, which is characterized by the absenceof a certain form F, and the end-state, which is characterized by the presenceof F. Something changes when it receives a certain form F from a certainagent. By receiving that form, the thing that is changed (i.e. the patient)actualizes a certain power or capacity (i.e. a “passive power”) that it had evenbefore being changed. For example, water becomes hot when it receives theform heat from fire. When water becomes hot, water’s power to be hot isactualized. The same process can also be described from the point of view ofthe agent. Fire’s heating water is the very same process as water’s becominghot. By heating the water, fire actualizes a certain power or capacity (i.e. an“active power”) that it had even before actually heating.The main point of Aristotle’s analysis of change is that change is aprocess of form giving (from the agent’s point of view) or form reception (fromthe patient’s point of view), where the form given and received actualizes boththe agent’s active power to give a form and the patient’s passive power toreceive a form. 8In the third book of his De anima, Aristotle applied this account ofchange to both perception and thought. He accordingly interpreted perceptionand thought as changes or processes in which a certain form is given by anagent and received in a patient. When I perceive hot, I receive the form heat.Similarly, when I think about cats, I receive the form felinity. Morespecifically, the form felinity is received in my intellect (the patient) from theobject, i.e. cats (the agent), through the intermediary of the senses andimagination. Just as in any other sort of change, when I perceive and think I8 Phys. III, 3; Gen. et Corr. I, 7. See U. Coope, “Aristotle’s Account of Agency inPhysics III 3,” Proceedings of the Boston Area Colloquium in Ancient Philosophy 20 (2004): 201–221; ead., “Aristotle on Action,” Proceedings of the Aristotelian Society Supplementary Volume 81(2007): 109–137.4

am informed by an agent, i.e. I receive the form of the agent in my senses andintellect, respectively. 9Even though both perception and thought are changes, Aristotleacknowledged that they are very special kinds of changes. The key differencebetween perception and thought, on the one hand, and ordinary kinds ofchanges such as heating, on the other hand, is that a kettle becomes hot whenit is heated, but I do not become what I perceive or what I think about when Iperceive or think about something. Aristotle accounted for this peculiarfeature of perception and thought by saying that, in both perception andthought, the form of the thing cognized is received in the cognizer without thematter. 10 This is usually taken to mean that the form of the thing cognized isreceived in the cognizer without a corresponding change in the cognizer’smatter. For example, when I see a red fox, my senses receive the form redness,but my matter does not become disposed to the form redness the way the fox’smatter is disposed towards it. Accordingly, the fox is red, but I do not becomered when I see a red fox. Similarly, when I think about cats, my intellectreceives the form felinity, but my matter does not become disposed towardsthe form felinity the way the matter of cats is.A last point should be considered in Aristotle’s account of perceptionand thought as changes. In both perception and thought, just as in any otherkind of change, the agent’s form is one and the same form as the patient’sform. When fire heats a kettle, the same form heat is both in the fire and in thekettle. Similarly, when I see red, the same form redness is both in the redobject and in my eye. And when I actually think about cats, the same formfelinity is both in cats and in my intellect. In the words of a contemporaryscholar, “forms are present in the world in two irreducible different ways, oneof which is cognitive of the other.” 11Some problems arise, however, when one considers in what sense of“the same” the form in the thing cognized is the same as the form in thecognizer. For this claim can be interpreted in two different ways. First, the9 De anima II, 5, 416b33–34 and 418a3–6; II, 12, 424a17–24; III, 4, 429a13–18 and429b29–430a2. See M. F. Burnyeat, “Aquinas on ‘Spiritual Change’ in Perception,” in Ancientand Medieval Theories of Intentionality, ed. D. Perler (Leiden/Boston/Köln: Brill, 2001), 139–142;C. Shields, “Intentionality and Isomorphism in Aristotle,” Proceeding of the Boston AreaColloquium in Ancient Philosophy 11 (1995): 308–310; id., Aristotle (London/New York:Routledge, 2007), 293–305; id., “The Peculiar Motion of Aristotelian Souls,” Proceedings of theAristotelian Society. Supplementary Volume 81 (2007): 140, 145–150.10 De anima II, 5; II, 12, 424a17–24. There is some debate concerning the correctinterpretation of this passage and related ones. See R. Sorabji, “Intentionality and PhysiologicalProcesses: Aristotle’s Theory of Sense-Perception,” in Essays on Aristotle’s De Anima, eds. M. C.Nussbaum and A. O. Rorty (Oxford: Clarendon Press, 1992), 217–218; Burnyeat, “Aquinas on‘Spiritual Change’,” 139–140. I follow Burnyeat’s interpretation.11 Burnyeat, “Aquinas on ‘Spiritual Change’,” 141.5

form of the thing I am thinking about and the form in my intellect may beregarded as the same individual item, i.e. numerically one and the same form.Second, the form of the thing I am thinking about and the form in my intellectmay be regarded as two discrete individuals, which are the same in someimportant respects but are not numerically the same item. The way these twonumerically distinct individuals are one and the same is variously described as“formal” or “structural sameness.” 12 Both interpretations have had theirsupporters among Aristotle’s interpreters. The former interpretation wasfavored in antiquity by Porphyry, according to Avicenna’s testimony, and hasreceived support by several contemporary scholars. 13 The latter interpretationwas explicitly endorsed by Avicenna in opposition to Porphyry and has alsoreceived support in recent years. 14 It was the latter interpretation that wascommonly adopted in the later Middle Ages. Ever since Aristotle’s De animawas translated into Latin and became the object of study (roughly between thetwelfth and the thirteenth century), medieval thinkers agreed on readingAristotle as positing two numerically distinct items, one in the thing I amthinking about and the other one in my intellect. In the thirteenth century, theform existing in my intellect was commonly called “intelligible species” inorder to distinguish it from the form existing in the thing I am thinking about. 15In light of this short outline of Aristotle’s position, his answers to thethree questions concerning what it is to think about something can bereconstructed as follows. First, an act of thinking is an instance of change.More precisely, an act of thinking is a passion, i.e. the reception of a certainform in a subject, i.e. in the intellect, from a certain agent, i.e. from theobject. 16 Second, an act of thinking occurs when the causal process of formimpression and reception started at the level of the senses ends up in the12 For the distinction between these two readings, which Christopher Shields calls“stronger” and “weaker hypothesis,” see Shields, “Intentionality and Isomorphism,” 324–327.13 Avicenna, Liber de anima, pars V, c. 6, 136. Among contemporary interpreters whosympathize with this view, see L. A. Kosman, “Perceiving that We Perceive: On the Soul III, 2,”The Philosophical Review 84 (1975): 499–519; J. Owens, “Aristotle: Cognition a Way of Being,”Canadian Journal of Philosophy 6 (1976): 1–11, reprinted in id., Aristotle: The Collected Papers ofJoseph Owens, ed. J. R. Catan (Albany: SUNY Press, 1981), 74–80; C. Kahn, “Aristotle onThinking,” in Essays on Aristotle’s De anima, ed. Nussbaum and Rorty, 372–375. See also J.Owens, Cognition: An Epistemological Enquiry (Houston, TX: Center for Thomistic Studies, 1992),114.14 Avicenna, Liber de anima, pars V, c. 6, 134–135. See D. L. Black, “Conjunction andthe Identity of Knower and Known in Averroes,” American Catholic Philosophical Quarterly 73(1999), 162–163; M. Sebti, Avicenne. L’âme humaine (Paris: Presses universitaires de France,2000), 97–99. Among contemporary interpreters who sympathize with this view, see Shields,“Intentionality and Isomorphism,” 324–330.15 On the history of the notion of intelligible species, see L. Spruit, Species Intelligibilis.From Perception to Knowledge (Leiden/New York/Köln: Brill, 1994); G. Pini, “Il dibattito sullespecie intelligibili nel tredicesimo secolo,” Medioevo 29 (2004): 267–306.16 Aristotle, De anima III, 4, 429a13–15; b22–25.6

intellect. Third, an act of thinking is about something, and more specifically acertain act of thinking is about a certain thing, because the form received inthe intellect is the form of a certain thing, say the form of cats rather than ofdogs (as I have mentioned, it is controversial whether the identity between theform in the intellect and the form of the object is numerical or specific).The strong point of Aristotle’s view that thinking is a passion is that itexplains the occurrence of thinking within the framework of naturalphilosophy. No special sort of entities are presupposed and no special sort ofchange is postulated. The same hylomorphic framework that explains changein general can be applied to thinking (as well as to perception). This approachhas the great advantage of dissolving the mystery concerning intentionality. Acertain thought is about a certain thing because it is the reception of the formof that thing, just as water is heated rather than cooled because it is the formheat rather than the form cold that is received in water.Aristotle’s account of thinking, however, faces some problems. I willmention two that are potentially fatal to the ultimate success of Aristotle’shylomorphic model in explaining thinking.First, the claim that to think is a kind of passion clashes with the basicintuition that to think is something I do rather than something that is done tome. In this respect, thought seems to be different from perception. It is not upto me to feel cold or hot, but it is up to me to think about something or notand to think about a certain thing rather than another, say about cats ratherthan dogs. I will call this the “activity problem.”Second, the view that to think about something is to undergo achange and more specifically to receive a form from the object provides agood account of learning, i.e. the passage from ignorance to dispositionalknowledge. When I am ignorant of what cats are, I have the power to acquirethe form felinity and to keep it stored in my memory. Just as in any otherchange, a certain state (i.e. ignorance, which is the privation of a certain form)is displaced by another state (i.e. dispositional knowledge, which is thepresence of a certain form). Problems arise, however, when one tries toaccount for the passage from dispositional to occurrent knowledge, i.e. to theactual occurrence of a thought. When I already know what cats are and Iactually think about cats, my occurrent and episodic thought about what catsare does not displace any previous state. I still retain the form felinity I haveacquired. Similarly, when I exercise my mathematical abilities, mydispositional knowledge of mathematics is not displaced by my occurrentknowledge. In Aristotelian terms, the hylomorphic explanation of thinking asform reception works well to account for the passage from a state of firstpotentiality to a state of second potentiality (or first actuality) with respect to7

knowledge. This explanation is not equally satisfactory when used to accountfor the passage from second potentiality (or first actuality) to a state of secondactuality with respect to knowledge. Thus, the hylomorphic model shows itslimits when applied to the crucial case of the occurrence of episodicthoughts. 17 I will call this “the problem of occurrent thoughts.”Aristotle left these two problems as a legacy to his medievalinterpreters. Aquinas’s and Scotus’s accounts of thinking can be regarded asalternative strategies to solve them.2. Aquinas’s model of thinking: thinking as actingBy and large, Aquinas adopted Aristotle’s account of thinking.Specifically, he embraced Aristotle’s insight that to think is a kind of changeand can accordingly be explained as the presence of a form in a patient.Something is heated when it receives the form heat. Similarly, I think aboutwhat it is to be a cat when the form felinity is received in my intellect. In thisrespect, sensory and intellectual acts of cognition are similar. Just as the formheat is the formal principle of heating in fire, i.e. what makes fire actuallyheat, in the same way a certain sensible form is the formal principle ofsensation, i.e. what makes the sense actually sense the thing whose sensibleform it is. 18 Similarly, a certain form received in the intellect is what makes theintellect actually think about the thing whose form it is.Within this general framework, Aquinas had to face five questions.First, what is the relationship between the form in my intellect and the form ofthe thing I am thinking about, e.g. between the form felinity in my intellectand the form felinity as instantiated in extramental cats? Second, what sort ofchange is an act of thinking, a passion or an action? In other words, when Ithink about what it is to be a cat, does my intellect undergo a change or doesit cause a change? Third, if it is granted that an act of thinking is an action,what sort of action is it? Fourth, is the presence of a certain form in myintellect both necessary and sufficient for an act of thinking to occur? Fifth andfinally, what accounts for an act of thinking’s intentionality, i.e. for its beingabout what it is about?I will address each of these questions in turn.17 Aristotle faces this problem in De anima II, 5, 417b1–16. See Shields, “The PeculiarMotion,” 155–159; id., Aristotle, 299–300.18 ST I, q. 56, a. 2: “Et ita se habet obiectum unitum potentiae ad huiusmodi actionem,sicut forma quae est principium actionis in aliis agentibus: sicut enim calor est principium formalecalefactionis in igne, ita species rei visae est principium formale visionis in oculo.”8

2.1. The form in the intellect: the intelligible species as likenessWhat is the relationship between the form felinity present in myintellect when I think about what it is to be a cat and the form felinity as it isinstantiated in extramental cats?Aquinas followed Avicenna in rejecting the view that the form presentin my intellect is numerically the same as the form that plays the role of theorganizing principle of the thing I am thinking about. Rather, the form in myintellect and the form of the thing I am thinking about are two numericallydiscrete items. Following the standard usage of his time, Aquinas called theform in the intellect an “intelligible species.” He claimed that the relationshipholding between the intelligible species and the thing thought about is notnumerical identity but likeness (similitudo). Specifically, the intelligiblespecies is a likeness of the thing thought about. Thus, to cognize something isto have a likeness of that thing in the intellect, not to have that very thing inthe intellect:[…] That which is understood is within that which understandsthrough its likeness. And the saying that “what is actually understood is theactualized intellect” holds in this way: insofar as a likeness of the thingunderstood is the intellect’s form. (Similarly, a likeness of a sensible thing isthe form of the actualized sense.)19So far, Aquinas’s position is clear. There is considerable disagreement,however, concerning the way the claim that the intelligible species is alikeness should be understood. Some interpreters hold that the notion oflikeness should be interpreted by virtue of what is variously described as arelation of “co-formality” or “formal identity” or “sharing of form.” 20 The ideais that the intelligible species is a likeness of the thing thought about becausethe intelligible species and the thing thought about are formally identical, i.e.they share the same general form. Thus, the same general form felinity can beinstantiated in two different kinds of individuals, i.e. individual cats in the19 ST I, q. 85, a. 2, ad 1: “ […] intellectum est in intelligente per suam similitudinem. Etper hunc modum dicitur quod intellectum in actu est intellectus in actu, inquantum similitudo reiintellectae est forma intellectus; sicut similitudo rei sensibilis est forma sensus in actu.” TheEnglish translation is taken from Thomas Aquinas, The Treatise on Human Nature. Summatheologiae 1a 75–89. Translated, with Introduction and Comentary, by Robert Pasnau(Indianapolis/Cambridge: Hackett Publishing Company, 2002), 164.20 G. Klima, “Aquinas’s Proofs of the Immateriality of Intellect from the Universality ofThought,” Proceedings of the Society for Medieval Logic and Metaphysics 1 (2001): 19–28, onlineat http://faculty.fordham.edu/klima/SMLM/PSMLM1/PSMLM1.pdf; id., “Tradition andInnovation in Medieval Theories of Mental Representation,” Proceedings of the Society forMedieval Logic and Metaphysics 4 (2004): 4–11, on-line at http://faculty.fordham.edu/klima/SMLM/PSMLM4/PSMLM4.pdf; Stump, Aquinas, 273–275; King, “Rethinking Representation.”9

extramental world and individual intelligible species in the intellects of thosewho know what it is to be a cat. This interpretation has the great advantage ofdissipating the mystery surrounding the notions of likeness, similitude andrepresentation. A certain quality in my intellect is a representation ofextramental cats just because that quality and extramental cats areinstantiations of the same general form. Of course, there remains to beexplained why the form felinity is instantiated in individual cats in theextramental world whereas there is no cat in my intellect when the formfelinity is received there. This is thought to depend on the kind of subject theform is received in. When the form felinity is received in some specific matter,i.e. some specific flesh, bones, etc., it acts as the organizing principle of thatmatter. By contrast, when the same general form felinity is received in anintellect, an intelligible species, i.e. a likeness of a cat, is produced. In turn, itmay be claimed that the intellect is the sort of subject that receives formswithout becoming the thing whose form it receives because the intellect is animmaterial subject. 21Several passages in Aquinas’s writings lend support to thisinterpretation. From a general point of view, Aquinas held that two things arealike when they share the same form. Thus, he did not seem to assume therelationship of likeness as primitive. Rather, he reduced that relationship to thesharing of the same form. 22 More specifically, Aquinas referred to the form inthe intellect and the form of the thing thought about as the same forminstantiated in two subjects, just as the same color is present in differentshades in different subjects. 23 There is of course a fundamental difference21 Aquinas, Sent. II, d. 3, q. 1, a. 1, ad 3 (Mandonnet, 88–89); De ente, 4, 375.11–-375.23; CG II, 50, n. 1261 and n. 1264; CG II, 91, n. 177 (“immunitas materiae confert esseintelligibile”); ST I, q. 50, a. 2; De substantiis separatis, 7 (Leon. 40, D 52.19–44). See R. Pasnau,Theories of Cognition, 31–60; id., “What Is Cognition? A Reply to Some Critics,” AmericanCatholic Philosophical Quarterly 76 (2002): 483–490.22 See for example Sent. II, d. 15, q. 1, a. 2, ad 4: “Similia sunt quae in eadem formacommunicant.” Admittedly, Aquinas also held that there is another kind of likeness, according towhich two things are alike if they are related to different terms in the same way. For example, amayor can be said to be like a captain because the mayor is related to a city just as the captain isrelated to a ship. The mayor and the captain, however, share no common form, since the kind ofauthority that the mayor has over a city is different from the kind of authority that a captain hasover a ship. See Sent. I, d. 34, q. 3, a. 1, ad 2. This kind of likeness, however, does not seem to berelevant to the case of the species and the object of cognition, for in the latter case only two (andnot four) terms are involved, i.e. the species and the object.23 ST I, q. 84, a. 1: “Hoc autem [scil., quod forma cogniti ex necessitate sit incognoscente eo modo quo est in cognito] necessarium non est. Quia etiam in ipsis sensibilibusvidemus quod forma alio modo est in uno sensibilium quam in altero: puta cum in uno est albedointensior, in alio remissior, et in uno est albedo cum dulcedine, in alio sine dulcedine. Et per huncetiam modum forma sensibilis alio modo est in re quae est extra animam, et alio modo in sensu,qui suscipit formas sensibilium absque materia, sicut colorem auri sine auro. Et similiterintellectus species corporum, quae sunt materiales et mobiles, recipit immaterialiter et10

etween the case of the color and that of an intelligible species. While eachinstance of white is an individual quality belonging to the same species, i.e.the color white, an extramental cat and my intelligible species of a cat are nottwo individuals belonging to the same species cat. This, however, can beexplained by the fact that in order for an individual cat to exist, the formfelinity must be instantiated in a certain portion of matter. But this is preciselywhat does not happen when the form felinity is received in my intellect, sincemy intellect is immaterial. 24Other interpreters, however, hold that this interpretation of Aquinasends up committing him to several implausible claims. Accordingly, theseinterpreters argue that the notion of likeness or similitude should be assumedas primitive. That something represents something else cannot be explained interms of sharing the same form. Rather, this should be assumed as brute fact. 25Nothing of what follows, however, depends on which of these twointerpretations of Aquinas is favored. No matter whether the form in theintellect is the same or not as the form of the extramental thing that is beingcognized, it is clear that in order for somebody to have intellectual cognitionof something it is necessary for her to have a form in her intellect. And it alsoclear that such a form comes to be present in her intellect in consequence of achange.2.2. Acts of thinking as actionsSo what kind of change is that by which the intelligible species comesto be present in the intellect?At times, Aquinas seemed to be endorsing Aristotle’s claim that tothink is to undergo a change. Thus, acts of thinking should be regarded asinstances of passions as opposed to actions. For example, when I think aboutwhat it is to be a cat, my intellect receives the form felinity from real cats. Inthat change, real cats play the role of agents while my intellect plays the roleof a patient. Thus, my act of thinking is something that cats do to me, notsomething that I literally do. Cats impress their forms on my intellect, just asfire impresses the form heat on a kettle. Aquinas suggested that this is whatactually happens when he contrasted the way human beings cognize to divineand angelic cognition. Unlike God and angels, human beings receive theimmobiliter, secundum modum suum: nam receptum est in recipiente per modum recipientis.”See also De substantiis separatis, 7: “ […] sic enim intellectus intelligit rem secundum quod formaeius in ipso existit.”24 See above, note 21.25 C. Panaccio, “Aquinas on Intellectual Representation,” in Ancient and MedievalTheories of Intentionality, 185–200; Brower and Brower Toland, “Aquinas on MentalRepresentation.”11

forms of what they think about as a result of an action of those things on theirintellects:There is a difference on this point between the human mind, whichderives forms from things, and the divine or angelic minds, which do notdraw their cognition from things. In the mind which depends on things fromknowledge, the forms exist because of a certain action of things on the soul.But, since all action is through form, the forms in our minds first and mainly26refer to things which exist outside our soul according to their forms. (Italicsmine)This, however, should be taken as a very general description of whathappens when I think about something. Any time Aquinas provided a moredetailed account of what it is to think, he argued that the claim that to cognizeis to undergo a change is true, strictly speaking, only of sensory cognition. Bycontrast, as far as thinking is concerned, Aquinas took into account what Ihave labeled the “activity problem” in Aristotle. When I think aboutsomething, it seems that I am genuinely doing something and that I am notmerely the subject of a change happening to me. That was also a view thatAquinas had to adopt as a consequence of his endorsement of the claim(which he could read in Augustine and which he thought that Aristotle himselfhad subscribed to) that nothing material can act on what is immaterial.Accordingly, no material object can act on the intellect. 27Thus, Aquinas readjusted the Aristotelian account of intellectualcognition in order to make room for the intellect’s active role in the process ofthinking. 28 He obtained this result by a threefold strategy. First, he argued that,26 De Ver., q. 10, a. 4: “Hoc autem differenter contingit in mente humana quae formasaccipit a rebus, et in divina vel angelica quae a rebus non accipiunt. In mente enim accipientescientiam a rebus, formae existunt per quandam actionem rerum in animam; omnis autem actioest per formam; unde formae quae sunt in mente nostra primo et principaliter respiciunt res extraanimam existentes quantum ad formas earum.” The English translation is from St. ThomasAquinas, Truth. Transl. by James V. McGlynn (Chicago: Henry Regnery Company, 1953), vol. 2,p. 19.27 See for example Augustine, In Genesi ad litteram, II, 16: “[…] non est putandumaliquid agere corpus in spiritum, tamquam spiritus corpori facienti, materiae vice subdatur. Omnimodo praestantior est qui facit, ea re qua aliquid facit.” For Aquinas’s endorsement of this claimand his conviction that Aristotle subscribed to that position, see ST I, q. 84, a. 6: “Intellectum veroposuit Aristoteles habere operationem absque communicatione corporis. Nihil autem corporeumimprimere potest in rem incorpoream. Et ideo ad causandam intellectualem operationem,secundum Aristotelem, non sufficit sola impressio sensibilium corporum, sed requirit aliquidnobilius, quia agens est honorabilius patiente, ut ipse dicit.”28 As a matter of fact, Aquinas thought that he was merely embracing Aristotle’sgenuine doctrine. It is clear, however, that he ended up holding a position that was not identicalwith Aristotle’s. It is also clear that Aquinas’s interpretation of Aristotle’s cognitive psychology washighly indebted to the late ancient tradition of Aristotelain commentators, specifically to12

even though the material object does not act on the intellect, the intellect doesnevertheless receive its form. Second, he granted that the object plays somecausal role in the act of thinking, even though he dramatically curtailed thatrole. Third, he distinguished between the intellect’s reception of the object’sform, on the one hand, and, on the other hand, the intellect’s act of thinkingproper.Concerning the first point, Aquinas held that the form of an object isimpressed on the intellect not by that object but by the intellect itself.Specifically, Aquinas distinguished between an active and a passive role theintellect plays in cognition. Both roles are played by numerically the sameintellect. In its active role, the intellect performs an operation called“abstraction,” which results in the production of a mental quality that has thesame form as the sensory impressions and the images caused by the object.That mental quality is nothing else than the intelligible species, Thus, theintelligible species is produced by the agent intellect, not by the object. It is,nevertheless, a representation of the object, because its form is the same asthat of the object (or is a representation of the form of the object), even thoughits way of existing is different, i.e. immaterial rather than material. Just like anyordinary action, the agent intellect’s production of the intelligible species canbe analyzed into the agent’s production of a form in a patient. The agentintellect plays the role of agent in that process. The form produced andreceived is the intelligible species. As to the patient, its role is played by theintellect itself, taken in its passive role, i.e. the so-called “possible intellect.” 29Concerning the second point, Aquinas held that the object, throughthe intermediary of its sensory image (the so-called “phantasm”), plays somecausal role in intellectual cognition. Admittedly, the image of an object is notthe sole or even the principal agent in the process of reception of that object’sform in the possible intellect. Rather, the agent intellect is the main agent inthat production. The image of the object, however, plays the role of“instrumental or secondary agent.” Even though the details of this view maynot be completely clear, Aquinas intended to reject the claim that the object,through the intermediary of its sensory image, plays a merely accessory andnon-causal role in the process of intellectual cognition. By contrast, theThemistius, as evidenced by notes to the Leonine edition of Aquinas’s commentary on Aristotle’sDe anima. 29 ST I, q. 79, a. 2–4; q. 85, a. 1. See Pasnau, Thomas Aquinas on Human Nature, 310–318; Stump, Aquinas, 263–264. On the role of the agent intellect in Aristotle and the controversialintepretation of De anima III, 5, see M. Frede, “La théorie aristotélicienne de l’intellect agent,” inCorps et âme. Sur le De anima d’Aristote, ed. G. Romeyer Dherbey and C. Viano (Paris: Vrin,1996), 377–390; M. F. Burnyeat, Aristotle’s Divine Intellect (Milwaukee: Marquette UniversityPress, 2008).13

object’s sensory image is a real agent in the process of intellectual cognition,even though it cannot act without the agent intellect’s intervention. 30Subsequently, Aquinas preferred to refer to sensory images as something like(quodammodo) the matter on which the agent intellect performs its action. 31 Inboth cases, the object and its image can be described as a necessary but notsufficient cause of an intelligible species.Aquinas’s contention that the object plays a causal role in the act ofthinking was the key move that allows him to explain an act of thinking’sintentionality. It is because an object, through its sensory image, has a causalrole in the process of intellectual cognition that the form received in theintellect is the form of a certain object. 32 Consequently, the act of thinkingtriggered by the reception of a certain form is an act of thinking about acertain object because it is the reception of form of that object that triggeredthat act of thinking.It is the third point in Aquinas’s strategy, however, that is particularlyworth noticing. Aquinas held that, once the possible intellect receives theform of a certain object from the agent intellect, the possible intellect becomesitself an agent.This point may be easily missed. Because the human intellect ispotential with respect to its operation of actually thinking about something, itmust be made actual by the reception of a form (i.e. an intelligible species).Before learning what it is to be a cat, I only have the capacity to think aboutcats. Thus, in order to actually think about what it is a cat, I must receive theform felinity in my possible intellect. According to Averroes’ interpretation ofAristotle, this is just what to think is. Once the possible intellect receives the30 De Ver., q. 10, a. 6, ad 7: “Ad septimum dicendum quod in receptione quaintellectus possibilis species rerum accipit a phantasmatibus, se habent phantasmata ut agensinstrumentale vel secundarium, intellectus vero agens ut agens principale et primum; et ideoeffectus actionis relinquitur in intellectu possibili secundum condicionem utriusque et nonsecundum condicionem alterius tantum; et ideo intellectus possibilis recipit formas ut intelligibilesactu ex virtute intellectus agentis, sed ut similitudines determinatarum rerum ex cognitionephantasmatum […].”31 ST I, q. 84, a. 6: “[…] ex parte phantasmatum intellectualis operatio a sensucausatur. Sed quia phantasmata non sufficiunt immutare intellectum possibilem, sed oportet quodfiant intelligibilia actu per intellectum agentem; non potest dici quod sensibilis cognitio sit totaliset perfecta causa intellectualis cognitionis, sed magis quodammodo est materia causae.” Aquinasrejected the view that senses and sensory images merely provide the intellect with an opportunityfor producing the intelligible species or obtaining them from something else (such as a separateintelligence). Rather, the senses and sensory images play a genuinely causal role in the productionof an intelligible species. See ST I, q. 84, a. 4.32 See in particular the last clause of the text quoted above, at note 30.14

form abstracted by the agent intellect, an act of thinking occurs. According toAverroes, there is nothing more to thinking than abstraction. 33Aquinas, however, did not adopt this position. Even though thepossible intellect’s reception of a species is necessary for an act of thinking tooccur, nevertheless an act of thinking is not identical with the possibleintellect’s reception of a species. By contrast, Aquinas held that the receptionof a species is necessary only because the human intellect is potential withregard to its act. By itself, however, to think about something is not to receivea species. It is a distinct event. 34Accordingly, it is necessary to distinguish two different actions carriedout by the intellect in the process of thinking. First, there is the agent intellect’sact of abstracting an intelligible species and of impressing it on the possibleintellect. In this process, the possible intellect plays the role of a patient.Second, there is the act of thinking proper. The act of thinking is performed bythe possible intellect once it has received the intelligible species. In the latterprocess, the possible intellect plays the role of an agent. These two processescan be compared to sense’s being changed by a sensory object and theimagination’s forming of a sensory image. In sensory cognition, these twoprocesses are carried out by two distinct powers, i.e. sense and imagination,respectively. By contrast, in intellectual cognition both processes are carriedout by the intellect. Nevertheless, they are two distinct actions. It is one thingfor the possible intellect to pass from a potential to an actual state thanks tothe reception of a form. It is another thing for the possible intellect, once it hasbeen made actual, to carry out its own operation. The possible intellect’s actof reception is a passion. The possible intellect’s act of thinking is an action. 3533 Averroes, Commentarium magnum in Aristotelis de anima libros, ed. F. StuartCrawford (Mediaeval Academy of America: Cambridge, Mass., 1953), 439: “Abstrahere enim nihilest aliud quam facere intentiones ymaginatas intellectas in actu postquam erant in potentia;intelligere autem nichil aliud est quam recipere has intentiones.” Some years after Aquinas,Godfrey of Fontaines quoted Averroes’ position with approval in his Quodl. V, q. 10 (PhB 3, 38–39). See J. F. Wippel, “The Role of the Phantasm in Godfrey of Fontaines’ Theory of Intellection,”in C. Wenin (ed.), L’homme et son univers au Moyen Age (Louvain-la-Neuve: Éditions de l’InstitutSupérieur de Philosophie, 1986), 573–582, at 579, note 19.34 ST I, q. 14, a. 2: “Ex hoc enim aliquid in actu sentimus vel intelligimus, quodintellectus noster vel sensus informatur in actu per speciem sensibilis vel intelligibilis. Etsecundum hoc tantum sensus vel intellectus aliud est a sensibili vel intelligibili, quia utrumque estin potentia.” See also ST I, q. 56, a. 2.35 ST I, q. 85, a. 2, ad 3: “In parte sensitiva invenitur duplex operatio. Una secundumsolam immutationem: et sic perficitur operatio sensus per hoc quod immutatur a sensibili. Aliaoperatio est formatio, secundum quod vis imaginativa format sibi aliquod idolum rei absentis, veletiam nunquam visae. Et utraque haec operatio [scil. immutatio et formatio] coniungitur inintellectu. Nam primo quidem consideratur passio intellectus possibilis secundum quodinformatur specie intelligibili. Qua quidem formatus, format secundo vel definitionem veldivisionem vel compositionem, quae per vocem significatur.”15

It may be useful to illustrate this distinction with a comparison.Consider a light bulb. When the light is on, it is possible to distinguish twoseparate processes. On the one hand, the light bulb receives electricity in itscircuits. On the other hand, that light bulb, once it has received electricity inits circuit, gives out light. Even though these two actions occursimultaneously, they should be considered as distinct. Each action has its owneffect. The first action’s effect is the illumination of the bulb. The secondaction’s effect is the bulb’s illuminating its environment. 36By this threefold strategy, Aquinas managed to keep the advantages ofAristotle’s account while making room for the intellect’s active role in the actof thinking. The act of thinking can still be interpreted as a change or process.In that process, the intellect plays the role of a patient. Both the object and theintellect, however, play the role of agents. Because the object, by virtue of itssensory image, performs a causal role in the act of thinking, an act of thinkingis about a certain thing. Specifically, an act of thinking is about the thingwhose sensory image plays the role of agent (in some way) of that act. Thus,the intentionality of an act of thinking is explained by the causal role that itsobject plays on that act. By contrast, it is because the intellect is active withregard to acts of thinking that my acts of thinking are something that I do, notsomething that is done to me. This is true at two levels. First, the intellectabstracts a mental quality form the sensory image of an object. Second, theintellect, made actual by that quality, performs the act of thinking as its ownproper activity.The elegance of Aquinas’s account of thinking resides in the claimthat numerically the same mental quality (i.e. the intelligible species) is bothwhat represents an extramental object and what actualizes the intellect’spower to think. 37 Because of this twofold function of the intelligible species,the act of thinking is both an action performed by the intellect and an actabout something in the world.36The distinction between these two actions may be made apparent if we leave the firstaction untouched but we tamper with the second, for example by putting a sheet of opaque paperaround a bulb. The bulb is still illuminated but does not illuminate anymore.37 De Ver., q. 10, a. 4: “Dicendum, quod omnis cognitio est secundum aliquamformam quae est in cognoscente principium cognitionis. Forma autem huiusmodi dupliciter potestconsiderari: uno modo secundum esse quod habet in cognoscente, alio modo secundumrespectum quem habet ad rem cuius est similitudo. Secundum quidem primum respectum facitcognoscentem actu cognoscere, sed secundum respectum secundum determinat cognitionem adaliquod cognoscibile determinatum […].” Specifically concerning intellectual cognition, see ST I,q. 85, a. 2, ad 1: “ […] intellectum est in intelligente per suam similitudinem. Et per hunc modumdicitur quod intellectum in actu est intellectus in actu, inquantum similitudo rei intellectae estforma intellectus; sicut similitudo rei sensibilis est forma sensus in actu.” See also ST I, q. 85, a. 5;Sent. libri de anima, II, 24, pp. 168–169.16

2.3. Acts of thinking as self-contained actions: Aquinas’s two accountsSo Aquinas could reconcile the main elements of Aristotle’s accountwith his key insight that acts of thinking are actions carried out by theintellect. To think is not a change the intellect undergoes but a change theintellect effects. Aristotle’s description of the intellect as a passive power canbe maintained, but only if it is interpreted in a very specific way. The intellectis a passive power only in the sense that, by its essence, it is not actual, i.e. itis capable of thinking but does not actually think. In order to actually think,the intellect must be made actual. This happens only when the intellectreceives a form. 38 It is the intellect itself, however, that makes itself actual byabstracting a form from the sensory image of an object and by impressing it onitself. What is more, once the intellect has impressed on itself the form of anobject, it becomes an agent in the process of thinking. Thus, to think issomething I do, not something that is being done to me, even though, in orderfor me to carry out an act of thinking, I must receive some information aboutwhat I am thinking about via the senses and the imagination.Specifically, Aquinas held that the act of thinking is a self-containedor immanent action. Like Aristotle, Aquinas distinguished between two kindsof actions. Some actions produce a result distinct from the exercise of theaction itself. They are accordingly called “transitive actions.” For example,fire’s action of heating produce the form heat, which is distinct from the actionof heating and is received in a patient such as a kettle. Other actions,however, do not produce any result distinct from their mere exercise. They areaccordingly called “immanent” or “self-contained actions.” 39 Aquinas heldthat cognitive and appetitive acts, such as sensing, imagining, thinking andwilling, are self-contained actions, which he also called “activities”38 ST I, q. 79, a. 2. See also Sent. I, d. 3, q. 1, a. 1.39 Aristotle Meta. IX, 8, 1050a23–b6. See Aquinas, CG III, 2: “Actio vero quandoquequidem terminatur ad aliquod factum, sicut aedificatio ad domum, sanatio ad sanitatem:quandoque autem non, sicut intelligere et sentire. Et si quidem actio terminatur ad aliquodfactum, impetus agentis tendit per actionem in illud factum: si autem non terminatur ad aliquodfactum, impetus agentis tendit in ipsam actionem.” Aquinas drew this distinction between twokinds of actions in many passages of his works. See for example Super I Sent., d. 40, q. 1, a. 1, ad1; De Ver., q. 8, a. 6; q. 14, a. 3; De Pot., q. 3, a. 15; q. 8, a. 1; CG II, 23, n. 993; ST I, q. 18, a. 3,ad 1; q. 23, a. 2, ad 1; q. 27, a. 1; q. 27, a. 3; q. 27, a. 5; q. 28, a. 4; q. 54, a. 1, ad 3; q. 54, a. 2;q. 56, a. 1; q. 85, a. 2; ST I-II, q. 3, a. 2, ad 3; De unitate intellectus, 3; In Meta. IX, lect. 8, nn.1862–1865; In Meta. VI, lect. 1, n. 1152; IX, lect. 2, n. 1788; XI, lect. 7, n. 2253. On Aristotle’sdistinction, see Makin’s commentary in Aristotle, Metaphysics. Book Θ. Translated with anIntroduction and Commentary by S. Makin (Oxford: Clarendon Press, 2006), 200–204. OnAquinas’s use of Aristotle’s distinction see B. Lonergan, Verbum: Word and Idea in Aquinas(Toronto: Toronto University Press, 1997 4 ), 128–133; Pasnau, Thomas Aquinas on Human Nature,352.17

(operationes). 40 He actually held that only cognitive and appetitive acts areself-contained actions. All natural actions are transitive. 41Aquinas, however, gave two alternative analyses of self-containedactions. In his first account, a self-contained action is an action that consistsmerely in an agent’s exercise of an activity that produces no result distinctfrom the activity itself. In his second account, a self-contained action is anagent’s exercise of an activity that does produce an effect distinct from theactivity itself. Contrary to what happens in transitive actions, however, theeffect of a self-contained action remains within the agent and is received in nopatient.Accordingly, Aquinas gave two alternative analyses of acts ofthinking as actions. In his first analysis, an act of thinking is an action that hasno end product distinct from the act of thinking itself. Thus, the term of thataction is not distinct from its principle; what makes an intellect actual is alsothe term of the intellect’s act. 42 In his second analysis, an act of thinking is anaction that results in the production of an internal term distinct from both theact and the form that makes the intellect actual. Specifically, the intellectproduces a concept, and that concept must be distinguished both from theintellect’s act of thinking and from the intelligible species received in theintellect. The species is the formal principle of an act of thinking. This meansthat the species is the form that makes the possible intellect actually thinkabout something. By contrast, the concept (which Aquinas called“conception” and “inner word”) is the term of an act of thinking, i.e. what the40 Aristotle himself had considered perception and thought as activities and hadcontrasted them to changes in a strict sense, because in activities there is no progress and no newform is acquired. See Aristotle, Meta. IX, 6, 1048b18–35 (a passage that was unknown tomedieval interpreters) and Nicomacheans Ethics X, 3–5. See J. L. Ackrill, “Aristotle’s Distinctionbetween Energeia and Kinesis,” in New Essays on Plato and Aristotle, ed. R. Bambrough (Londonand New York: Routledge, 1965), 121–141; M. F. Burnyeat, “Kinesis vs. Energeia: A Much-ReadPassage in (but not of) Aristotle’s Metaphysics,” Oxford Studies in Ancient Philosophy 34 (2008):219–292. 41 CG II, 23, n. 993.42 CG I 53, first draft, printed as Appendix II, A in Liber de Veritate Catholicae Fideicontra errores Infidelium seu Summa contra Gentiles, vol. 1, ed. C. Pera, P. Marc, and P.Caramello (Torino/Roma: Marietti, 1961). I quote the relevant passage here below, at note 52. Seealso ST I, q. 56, a. 2: “Sed in actione quae manet in agente, oportet ad hoc quod procedat actio,quod obiectum uniatur agenti: sicut oportet quod sensibile uniatur sensui, ad hoc quod sentiatactu. Et ita se habet obiectum unitum potentiae ad huiusmodi actionem, sicut forma quae estprincipium actionis in aliis agentibus: sicut enim calor est principium formale calefactionis inigne, ita species rei visae est principium formale visionis in oculo.” The same point is made in STI, q. 85, a. 2. On the three successive drafts of CG I, 53, see L.-B. Geiger, “Les rédactionssuccessives de Contra Gentiles I, 53, d’après l’autographe,” in Saint Thomas d’Aquin aujourd’hui(Paris: Desclée de Brouwer, 1963), 221–240.18

intellect produces when it performs the action triggered by the reception ofthe species. 432.4. Dispositional versus occurrent knowledgeSo far, I have presented Aquinas’s position as if the abstraction/reception of a species were both necessary and sufficient for an act of thinkingto occur. Granted that the act of abstraciton and the act of thinking triggeredby the reception of a species are two distinct acts, Aquinas seems indeed attimes to suggest that an act of thinking occurs if an only if a species isabstracted and received. 44 This cannot be the case, however. For Aquinas wasalso aware of what I have called Aristotle’s “problem of occurrent thought.” Ifthe presence of a form in the intellect were sufficient for an act of thinking tooccur, one of the following two undesirable scenarios would obtain: eitherany time I think about something I carry out a new act of abstraction and Iacquire a new intelligible species or I always think about all the things ofwhich I have a species in my intellect. Both situations, however, areunacceptable for Aquinas. He rejected the first option in his confutation ofAvicenna’s position. Avicenna held that, when I do not actually think aboutsomething, I have no intelligible species of that thing in my intellect. Bycontrast, Aquinas claimed that once I have learned something, I keep anintelligible species of that thing stored in my intellect even though I am notactually thinking about it. Thus, according to Aquinas, the difference between43 CG I, 53 (third and definitive draft); CG IV, 11; ST I, q. 27, a. 1; q. 28, a. 4, ad 1; q.34, a. 1; q. 85, a. 2, ad 3; De Pot., q. 8, a. 1; q. 9, a. 5; Quodl. V, a. 2; Super Evang. Ioan., I, 1;De spirit. creat., 9. Some elements of this account were already present in De Ver., q. 4, a. 2.Aquinas developed his second analysis of acts of thinking mostly because of theological reasonsconnected with the evolution of his understanding of the Trinity. But he explicitly applied his newanalysis to human thinking. The second account was supposed to replace the first one, but as amatter of fact Aquinas still referred to his first account in ST. On Aquinas’s evolution in thisrespect, see See H. Paissac. Théologie du Verbe. Saint Augustin et Saint Thomas (Paris: LesÉditions du Cerf, 1951); R. Gauthier, Saint Thomas d’Aquin. Somme contre les gentils.Introductoin par René-Antoine Gauthier (Paris: Éditions universitaires, 1993), 105–108; A. F. vanGunten, “In principio erat Verbum. Une evolution de saint Thomas en théologie trinitaire,” inOrdo Sapientiae et Amoris. Hommage au Professeur Jean-Pierre Torrell OP à l’occasion de son 65 eanniversaire, ed. C.-J. Pinto de Oliveira (Fribourg, Suisse: Éditions universitaires, 1993), 119–141.On Aquinas’s first account, see J. Chênevert, “Le verbum dans le Commentaire sur les Sentencesde Saint Thomas d’Aquin,” Sciences ecclésiastiques 13 (1961): 191–233, 359–390. These twodifferent accounts are not usually distinguished in the most recent literature concerning Aquinas’stheory of intellectual cognition. Only the second account is usually taken into consideration. SeePanaccio, “Aquinas on Intellectual Representation,” 190–196; id., “From Mental Word to MentalLanguage,” Philosophical Topics 20 (1992): 125–147, esp. 126–129; id., Le discours intérieur dePlaton à Guillaume d’Ockham (Paris: Éditions du Seuil, 1999), 177–192; Pasnau, Theories ofCognition, 256–271; id., Thomas Aquinas on Human Nature, 327–328; Stump, Aquinas, 266–168. I will deal more in detail with Aquinas’s two accounts of the act of thinking in a separatepaper.44 See for example ST I, q. 14, a. 2, quoted above, note 34.19

eing in a state of ignorance and being in a state of knowledge with respect tosomething is a difference in the furniture of our intellect. 45This, however, does not mean that I always think about all I know.Aquinas held that there is a difference between dispositional and occurrentknowledge, or, in Aristotelian terms, between knowing something in firstactuality and knowing something in second actuality. 46 Accordingly, Aquinashad to reject the view that the presence of an intelligible species in theintellect is sufficient for an act of thinking to occur. But then, what else isrequired in addition to the abstraction/reception of a species in order for anact of thinking to occur?In order to account for the passage from dispositional to occurrentknowledge, Aquinas introduced the view that an intelligible species can berelated to the intellect in three ways. First, a species can be in the intellectonly potentially. In that case, I am ignorant of what something is, but I amable to learn what it is. Second, a species can be in the intellect in completeactuality, i.e. when I actually think about something. Third and crucially, aspecies can be present in the intellect in an intermediate way, which is neitherentirely potential nor entirely actual. In that case, I know what something isbut I do not think about it. Because a species can be present in thisintermediate way, I keep some knowledge of the things I have learned eventhough I do not always think about all the things I know:An intelligible species is sometimes present only potentially in theintellect, and then the intellect is said to be in potentiality. Sometimes it isthere inasmuch as the act is entirely complete, and then the intellect isactually thinking. Sometimes it stands midway between potentiality andactuality, and then the intellect is said to have a disposition. It is in this waythat the intellect preserves species, even when it is not actually thinking.4745 See De Ver., q. 10, a. 2; ST I, q. 79, a. 6; CG, II, 74; Quodl. III, q. 9, a. 1; Quodl. XII,q. 9, a. 1. See also De Ver., q. 19, a. 1; ST I-II, q. 67, a. 2. The position Aquinas rejected is foundin Avicenna, Liber de anima, pars 5, c. 6, 128–131. On Avicenna, see H. A. Davidson, Alfarabi,Avicenna, and Averroes on Intellect. Their Cosmologies, Theories of the Active Intellect, andTheories of Human Intellect (New York/Oxford: Oxford University Press, 1992), 83–94.46 See for example De malo, q. 1, a. 5: “Actus autem est duplex, scilicet primus, qui esthabitus uel forma, et secundus, qui est operatio, sicut scientia et considerare. Actu autem primoinherente adhuc est potentia ad actum secundum, sicut sciens nondum actu considerat setconsiderare potest.” The form that makes the possible intellect actual can be considered potentialwith respect to the intellect’s action. See Sent. IV, d. 49, q. 3, a. 2: “Ultimum autem etperfectissimum quod est in unoquoque est sua operatio; unde omnis forma inhaerens comparaturad operationem quodammodo ut potentia ad actum; propter quod forma dicitur actus primus, utscientia; et operatio actus secundus, ut considerare, ut patet in II de Anima.” For Aristotle, seeabove, n. 17.47 ST I, q. 79, a. 6, ad 3: “Ad tertium dicendum quod species intelligibilis aliquando estin intellectu in potentia tantum: et tunc dicitur intellectus esse in potentia. Aliquando autemsecundum ultimam completionem actus: et tunc intelligit actu. Aliquando medio modo se habet20

Aquinas never gave a detailed description of how the passage fromdispositional to occurrent knowledge takes place. It is very likely that theintelligible species is brought to the state of complete actuality by whatAquinas called the intellect’s “turning back towards the sensory images”(conversio ad phantasmata). By turning back to the sensory image from whicha certain intelligible species has been abstracted, the intellect revitalizes thatspecies, which until then was lying dormant in the intellect itself. 48 Thus, theprocess of thinking is cognate to the process of learning something. When theintellect learns something, it acquires a certain form for the first time. Bycontrast, when the intellect thinks about something, it re-acquire in fullactuality a form that had been partially forgotten and that was in a state ofincomplete actuality. This act of re-acquisition is effected through theintellect’s turning back towards the sensory image, which in turn is triggeredby an act of the will, which Aquinas calls by the Augustinian term of“attention” (intentio). 49 Thus, I actually think about what it is to be a cat if andonly if I decide to focus on the sensory image of a cat and in that way I bringback to my mind what I already know about cats.This explanation of the passage from dispositional to occurrentknowledge can be applied to both of the accounts of an act of thinking as aself-contained action that I have distinguished above. According to Aquinas’sfirst account, once the intelligible species is present in the possible intellect inits full actuality, the intellect itself performs an act of thinking whose innerterm is coincident with the species itself. By contrast, according to Aquinas’ssecond account, once the intelligible species is present in the possibleintellect in its full actuality, the intellect performs an act of thinking whoseinter potentiam et actum: et tunc dicitur esse intellectus in habitu. Et secundum hunc modumintellectus conservat species, etiam quando actu non intelligit.” The Enligh Translation is fromThomas Aquinas, The Treatise on Human Nature, trans. Pasnau, 92. See also De Ver., q. 10, a. 2,ad 4; De Ver., q. 19, a. 1; CG II, 74, n. 16; Quodl. III, q. 9, a. 1; Sent. libri de anima, III, cap. II, p.208.48 De Ver., q. 10, a. 2, ad 7: “Nulla potentia potest aliquid cognoscere nisi convertendose ad obiectum suum […]; unde […] quantumcumque aliquam speciem intelligibilem apud seintellectus habeat, numquam tamen actu aliquid considerat secundum illam speciem nisiconvertendo se ad phantasmata.” See also Quodl. XII, q. 9, a. 1: “[…] et non solum propter hoc[scil. corpus] phantasmata indigemus, sed ad utendum huiusmodi species.” And more in generalST I, q. 84, a. 7. See Pasnau, Theories of Cognition, 135–136; id., Thomas Aquinas on HumanNature, 284–295.49 De Ver., q. 13, a. 3: “[…] ad actum alicuius cognititivae potentiae requiriturintentio;” CG I, 55: “Vis cognoscitiva non cognoscit aliquid actu nisi adsit intentio: unde etphantasmata in organo conservata interdum non actu imaginamur, quia intentio non fertur ad ea.”See also Sent. I, d. 3, q. 5, a. 5: “Ad talem enim cognitionem non sufficiet praesentia rei quolibetmodo; sed oportet ut sit ibi in ratione obiecti, et exigitur intentio cognoscentis.” See Pasnau,Theories of Cognition, 134–135. For Augustine’s notion of attention, see Augustine, De Trin., XI,2.2–3.21

inner term is a concept produced by that very act. That concept is producedby the intellect only as long as the intellect actually thinks. When the intellectdoes not perform its action and the species recedes to a dormant state, noconcept is produced and present in the intellect. 50The main problem with the claim that an intelligible species can bepossessed in complete or incomplete actuality is that it sounds like an ad hocmove to account for the passage from dispositional to occurrent knowledge. Initself, the view that a form can be possessed in incomplete actuality isobscure. A form is just what makes something actual. In this case, anintelligible species is what brings the possible intellect to a state of actuality.So how can what makes something actual be possessed in incompleteactuality? There seems to be the risk of an infinite regress.2.5. Aquinas on the intentionality of acts of thinkingBoth in his first and in his second analysis of acts of thinking as selfcontainedactions, Aquinas held that the burden of intentionality is carried bythe intelligible species. Thus, a certain act of thinking is about a certain objectnot because that act is related to that object but because it is preceded andmade possible by the abstraction/reception of the intelligible species of thatobject. For example, my act of thinking about what it is to be a cat is aboutthe essence of cats not because that act is related to that essence but becausethere is the intelligible species of cats in my possible intellect and that speciesmakes possible my intellect’s act of thinking.So intentional acts in general and acts of thinking in particular areacts that are not related to the things they are about. Aquinas was forced tothis paradoxical position by his view that intentional acts in general and actsof thinking in particular are actions, and more specifically self-containedactions. According to his first account, self-contained actions are actionswhose term coincide with the form that triggers them. Thus, an act of thinkingis related only to an intelligible species, not to an extramental thing.According to Aquinas’s second account, self-contained actions are actionsthat produce their own inner term. Thus, an act of thinking is related to theconcept it produces, not to the extramental thing it is supposed to be about. In50 De Pot., q. 8, a. 1: “[Conceptio] [d]iffert autem a specie intelligibili: nam speciesintelligibilis, qua fit intellectus in actu, consideratur ut principium actionis intellectus, cum omneagens agat secundum quod est in actu; actu autem fit per aliquam formam, quam oportet esseactionis principium. Differt autem ab actione intellectus: quia praedicta conceptio consideratur utterminus actionis, et quasi quoddam per ipsam constitutum.” Aquinas explicitly held that theconcept or inner word is present only when an act of thinking occurs in ST I, q. 93, a. 7: “Verbumautem in anima nostra sine actuali cognitione esse non potest, ut Augustinus dicit 14 De Trin.”22

neither accounts is there room for a relation between an act of thinking andthe extramental thing it is about . 51But then, why is a certain act of thinking about a certain object? Whyis my act of thinking about what it is a cat about the essence of cats?According to Aquinas’s first account, the intentionality of an act ofthinking is due to that act of thinking’s being triggered by a likeness of acertain thing, i.e. by the intelligible species of a certain thing. It is theintelligible species, however, and not the act of thinking that is related to theextramental thing that is being thought about by virtue of that act of thinking.Thus, it is in some way improper to say that a certain act of thinking is aboutsomething. Rather, it would be more precise to say that the intellect becomesassimilated to a certain thing because it receives the form of that thing (i.e. anintelligible species) and the form of that thing is what activates the intellect,i.e. what makes it actually think. 52According to Aquinas’s second account of acts of thinking as actionswith internal terms, the intentionality of an act of thinking is explained in aneven more complicated way. A certain act of thinking is about a certain thingbecause the concept such an act produces is a likeness of its agent, i.e. of theintellect. Now any effect is a likeness of its cause insofar as that causeproduces that effect. A cause produces an effect insofar as that cause is actual.And what makes a cause actual is its form, whether essential or, as in thiscase, accidental. Since the intellect is made actual by an intelligible speciesand since that species is a likeness of an extramental object, the conceptproduced by the intellect, which is directly a likeness of the intellect, isindirectly a likeness of the extramental object. Thus, my act of thinking aboutwhat it is to be a cat is about the essence of cats because the concept51 The view that is being presupposed here is that an action is a relative item, and that,like any relative item, an action has a foundation (the form present in the agent) and a term atwhich it is directed (the form received in a patient or, more properly, the patient informed by thatform). For example, the action of heating is grounded on the form heat present in fire and directedat the form heat present in the kettle heated by fire or, more properly, the hot kettle. Similarly, anact of thinking is grounded on the intelligible species that actualizes the intellect and either has noterm distinct from that species (according to Aquinas’s first account) or is directed at the concept itproduces (according to Aquinas’s second account). On subjects and terms of relations, see M. G.Henninger, Relations. Medieval Theories 1250–1325 (Oxford: Clarendon Press, 1989), 4–6.52 CG I, 53, first draft: “Harum igitur potentiarum operatio non terminatur ad resexteriores neque sicut ad principium agendi neque sicut ad subiectum patiens, sed ad easterminatur sola relatio potentiae operantis, quae quidem relatio consequitur formam operantis perquam operatur: sicut imaginatio per formam relictam a sensu habet operationem propriam inimaginatione consistentem, ad rem vero exteriorem quam imaginatur habet relationem performam qua informatur, et ex hac relatione contingit quod imaginando cognoscit remimaginatam. Et similiter intellectus per formam intelligibilem qua intelligit, refertur quadamsimilitudinis relatione ad rem extra quam intelligendo cognoscit. Unde et dicitur quod scientia estassimilatio scientis ad rem scitam.”23

produced by my act of thinking is a likeness of my intellectnmade actual bythe intelligible species of cats, which in turn is a likeness of cats:And this [i.e. that a concept is a likeness of the thing thought about]happens because the effect is like its cause in respect of its form, and the formof the intellect is the thing understood. Wherefore the word that originatesfrom the intellect is the likeness of the thing understood […].53Thus, the term of my act of thinking is not an extramental thing, butthe concept produced by my act of thinking. It follows that what I am thinkingabout when I am thinking about what it is to be a cat is primarily the conceptof what it is to be a cat that my intellect forms. Only secondarily is my act ofthinking about the essence of cats. And the reason why my act of thinking is atleast indirectly an act of thinking about what it is to be a cat is that such an actwas triggered by the reception of the form felinity in my intellect. In turn, therelation between the concept produced by my intellect and the extramentalthing it represents is a relation of final causality: the thing is the end at whichmy concept is directed. 54 Aquinas also described the relation between theconcept my intellect forms and the thing it represents as a containmentrelation: the concept is that “in which” (in quo) I understand the extramentalthing. For example, my concept of what it is to be a cat is that “in which” Ithink about what it is to be a cat. Admittedly, it is not easy to make sense ofthis containment relationship. What Aquinas seems to be saying is that I thinkabout what it is to be a cat by thinking about the definitional account I form inmy intellect of what it is to be a cat. 55 As Aquinas also stated, the concept myintellect forms of what it is to be a cat is the tool by which I think about whatit is to be a cat. 5653 De Pot., q. 8, a. 1: “Et hoc ideo contingit, quia effectus similatur causae secundumsuam formam: forma autem intellectus est res intellecta. Et ideo verbum quod oritur ab intellectu,est similitudo rei intellectae.” The English translation is from Thomas Aquinas, On the Power ofGod. Literally Translated by the English Dominican Fathers (Burn Oates & Washbourne LTD.:London, 1932), vol. 3, 71.54 De Pot., q. 9, a. 5: “Hoc ergo est primo et per se intellectum, quod intellectus inseipso concipit de re intellecta.” See also De spir. creat., 9: “Intellectum autem, sive res intellecta,se habet ut constitutum vel formatum per operationem intellectus: sive hoc sit quidditas simplex,sive sit compositio et divisio propositionis.” For the extramental thing as the end at which aconcept is directed, see De Pot. q. 8, a. 1: “ […] et iterum conceptio intellectus ordinatur ad remintellectam sicut ad finem: propter hoc enim intellectus conceptionem rei in se format ut remintellectam cognoscat.”55 Super Evang. Ioan., I, 1: “Istud ergo sic expressum, scilicet formatum in anima,dicitur verbum interius; et ideo comparatur ad intellectum, non sicut quo intellectus intelligit, sedsicut in quo intelligit; quia in ipso expresso et formato videt naturam rei intellectae.”56 Quodl. V, a. 2, ad 1: “Ad primum ergo dicendum quod intellectus intelligit aliquiddupliciter: uno modo formaliter, et sic intelligit specie intelligibili qua fit in actu; alio modo sicut24

***Based on what I have said, these are Aquinas’s answers to the threequestions I have mentioned at the beginning of this paper:(1) An act of thinking is an item in the category of action. To thinkabout something is to do something. More specifically, an act of thinking is aself-contained action. But Aquinas had two accounts of self-contained actions.According to his first account, Aquinas held that such an action does notproduce anything. Thus, to think is a process that does not issue in any resultdistinct from itself. According to his second account, Aquinas held that suchan action does produce a term, but that term is not received in a patientdistinct from the agent itself. Thus, to think is a process of concept-formation.(2) The mere presence of a form (called “intelligible species”) in thepossible intellect is a necessary but not a sufficient condition for an act ofthinking to occur. In addition, that form must be present in complete actuality.This passage to complete actuality is probably effected by the intellect’sturning back to a sensory image. The intellect’s act of turning back to asensory image is in turn triggered by an act of will.(3) An act of thinking is about a certain thing because it is triggered bya certain form present in complete actuality in the possible intellect. By itself,an act of thinking is not related to its object. Rather, a certain act is about acertain object only because the intellect has been activated by a certain form.As I have mentioned, there are two particularly problematic aspectscommon to both formulations of Aquinas’s account of thinking (i.e. as an actthat produced nothing and as an act that produces an internal term). First,Aquinas had a hard time to account for the difference between dispositionaland occurrent knowledge. The notion of a species present in the intellectaccording to different degrees of actuality is clearly problematic. Second,Aquinas’s explanation of the intentionality of acts of thinking was remarkablyconvoluted. The very idea that an act of thinking is not directly related to itsobject is at first sight implausible. Both problems are consequences ofAquinas’s assumption that acts of thinking are actions. Accordingly, it doesnot come as a surprise that Scotus rejected that very assumption andapproached the whole issue from a different perspective.instrumento quo utitur ad aliud intelligendum, et hoc modo intellectus uerbo intelligit, quiaformat verbum ad hoc quod intelligat rem.”25

3. Scotus’s model of thinking: thinking as a qualityScotus laid the foundations of his account of thinking some forty yearsafter Aquinas had developed his most mature views on the subject. In theeventful period between Aquinas and Scotus, several thinkers subjectedAquinas’s treatment to careful scrutiny and sometimes harsh criticism. Amongthe elements that were most often criticized were Aquinas’s account ofabstraction and his analysis of the act of thinking as an act of conceptformation. Concerning the agent intellect’s act of abstraction, thinkers asdiverse as Henry of Ghent, 57 Godfrey of Fontaines 58 and Peter John Olivi 59eventually argued that the agent intellect’s act of abstraction does not result inthe production of an intelligible species in the possible intellect. ConcerningAquinas’s view that an act of thinking results in the production of a concept,Henry of Ghent 60 and William of Ware conceded that a concept is actuallyproduced when an act of thinking occurs but disagreed with Aquinas’sspecific analysis of how a concept is produced. Specifically, William ofWare’s criticism of Aquinas’s second account of acts of thinking as selfcontainedactions is particularly interesting as an anticipation of Scotus’sposition. Ware argued that Aquinas’s view that self-contained actions producesomething (i.e. a concept) was both unprecedented and in contrast withAristotle’s position. He also held that while transitive actions require anobject, self-contained actions do not. And most interestingly, he argued thatAquinas posited an unnecessary intermediate entity between an act ofthinking and the extramental thing that act is about. Thus, William of Ware,just as Peter John Olivi, rejected the very idea that when an act of thinkingoccurs anything apart from that act of thinking is produced. 6157 Henry of Ghent, Quodl. V, q. 14, ff, 174Y, 176O–177R. See Martin Pickavé’s paperin this volume. See in general T. V. Nys, De psychologia cognitionis humanae secundumHenricum Gandavensem (Rome: Gregorian University, 1947).58 Godfrey of Fontaines, Quodl. IX, q. 19 (PhB IV, 271–275). In general on Godfrey’sviews on abstraction, see Quodl. V, q. 10 (PhB III, 3540). See Wippel, “The Role of the Phantasmin Godfrey of Fontaines’ Theory of Intellection,” 573–582.59 Peter John Olivi, Quaestiones in secundum librum Sententiarum, q. 74, 106–135.See Pasnau, Theories of Cognition, 236–247.60 Henry of Ghent, Summa quaestionum ordinariarum, art. 58, q. 1, vol. 2, 124H–L.See S. P. Marrone, The Light of Thy Countenance: Science and Knowledge of God in theThirteenth Century (Leiden and Boston: Brill, 2001), 270–298; G. Pini, “Henry of Ghent’sDoctrine of Verbum in Its Theological Context,” in Henry of Ghent and the Transformation ofScholastic Thought: Studies in Memory of Jos Decorte (Leuven: Leuven University Press, 2003),307–326. 61 William of Ware, Sent. I, d. 27, q. 3, 258*–263*. It should be noticed that William ofWare is often thought to have been one of Scotus’s teachers. On Peter John Olivi, see Pasnau,Theories of Cognition, 271–276; id., “Petri Johannis Olivi Tractatus de Verbo,” Franciscan Studies53 (1993): 121–153, at 141–142.26

None of these authors, however, questioned the fundamentalassumption that acts of thinking are actions.Scotus was familiar with most of these criticisms of Aquinas’sposition. The main difficulty in reconstructing Scotus’s answers to the threequestions I have posed at the beginning of this paper is that he never gave acomprehensive treatment of what it is to think about something. Rather, hepreferred to position himself in the contemporary debate about specific issuessuch as the necessity of an intelligible species or the relationship between anact of thinking and its object. A further difficulty is that Scotus’s views evolvedfrom his first to his last works. As a consequence of these two difficulties,Scotus’s basic moves in his treatment of intellectual cognition may get lost inthe details and consequently be missed by his interpreters. This is a pity, forScotus’s originality seems to lie more in his general strategy to approach thequestion of what it is to think rather than in his detailed treatments of specifictopics, for which he is most often indebted to other thinkers.Scotus’s casual references to the mechanisms of intellectual cognitionin his early writings betray a rather crude understanding of the nature of an actof thinking. He initially held that any cognitive act is an action and he evenseemed to have identified acts of thinking and intelligible species. 62In just a few years, however, Scotus developed a sophisticatedposition on intellectual cognition. The main elements of this position can begathered from his writings dating from the years 1301–05, i.e. his Ordinatio,Reportatio I-A and Quodlibet. In those writings, Scotus made threecharacteristic moves. First, he distinguished between two actions, both ofwhich are ordinarily necessary for an act of thinking to occur. The first actionis the agent intellect’s act of abstraction and production of an intelligiblespecies. The second action is the process by which an act of thinking isproduced. Second, Scotus distinguished the act of thinking from the processby which an act of thinking is produced and he consequently argued that anact of thinking is a quality rather than an action. Third, he accounted for theintentionality of acts of thinking by introducing a special relation holdingbetween acts of thinking and their objects.I will consider each of these three aspects in turn.62 Scotus, Quaest. super Meta., V, q. 12–13, n. 98, OPh III, 638: “[…] cognitio est ingenere actionis […];” Quaestiones in duos libros Perihermeneias: In librum primum, q. 1, n. 14,OPh II, 139: “Ad cuius evidentiam sciendum quod tria se habent secundum ordinem. Primum estspecies intelligibilis, secundum quam intellectus est in actu, quae species est in intellectu sicutactus proprius in propria materia sua. Nam, sicut Commentator ait III De anima, sic se habetintellectus ad species intelligibiles, sicut materia prima se habet ad formas individuales quasrecipit. Secundum est quod est ratio rei quod est ‘quod quid est’ rei […]. Tertium est resparticulariter exsistens sub condicionibus individualibus.”27

3.1 Two actions: abstraction and the production of an act of thinkingScotus distinguished between two actions that must ordinarily takeplace in order for an act of thinking to occur. 63 The first action is the agentintellect’s abstraction of a form, the so-called “intelligible species,” from asensory image present in the imagination. This action is identical with thepossible intellect’s reception of the intelligible species, as the agent intellect’sproduction of a species and the possible intellect’s reception of a species arejust two descriptions of one and the same process. Against Henry of Ghentand Godfrey of Fontaines, Scotus argued that the agent intellect’s act ofabstraction is an act of producing a form in the possible intellect, becausesuch a form must be present in the intellect prior to the occurrence of an actof thinking. 64 Scotus’s argument for this claim was based on the assumption(which Scotus took to be self-evident) that the object of an act of thinking mustbe present to the intellect prior to the occurrence of that act of thinking as wellas on the further assumption that the object of an act of thinking (as far asabstractive cognition is concerned) is a universal, i.e. something like “what itis to be a cat” as opposed to “what it is to be this particular cat.” Given thesetwo assumptions, Scotus argued that only a form present in the intellect priorto the occurrence of an act of thinking could account for the presence of theobject prior to the occurrence of an act of thinking. 65 Since the form present inthe intellect prior to the occurrence of an act of thinking is the intelligiblespecies produced by the agent intellect, it follows that the agent intellect’sabstraction of a species is a pre-requisite for the occurrence of an act ofthinking and must be distinguished from it. 66Scotus regarded the agent intellect’s act of abstraction as a real action,i.e. a process that ends up in the production of a real quality, the intelligible63 I say “ordinarily” because God can bypass both actions and produce an act ofthinking immediately in my intellect, as I indicate below. Also, notice that here I am consideringacts of abstractive cognition.64 Ord. I, d. 3, p. 3, q. 1, Vat. III, 201–244; Lect. I, d. 3, p. 3, q. 1, Vat. XVI, 325–348;Rep. I-A, d. 3, q. 4 and q. 5, eds. Wolter and Bychkov, 207–220 and 221–232.65 Ord. I, d. 3, p. 3, q. 1, nn. 349–350, Vat III, 210–211. For Scotus’s argument thatonly a form present in the intellect can account for the presence of the object as a universal priorto the act of thinking, see Ord. I, d. 3, p. 3, q. 1, nn. 352–358, Vat. III, 211–216; Lect. I, d. 3, p. 3,q. 1, nn. 266–273, Vat. XVI, 331–334; Rep. I-A, d. 3, q. 4, nn. 95–97, eds. Wolter and Bychknov,210–211. See King, “Rethinking Representation.”66 Scotus contrasted the agent intellect’s act of abstraction to the act of thinking properin Ord. I, d. 3, p. 3, q. 1, n. 359–360, Vat. III, 216–218; Rep. I-A, d. 3, q. 4, n. 103, eds. Wolterand Bychknov, 212–213; Quodl., q. 15, n. 14, Vivès XXVI, 145. See also Lect. I, d. 3, p. 3, q. 1, n.275, Vat. XVI, 335.28

species. 67 That real quality, however, is also a representation of an extramentalthing, i.e. it has an intentional content. It is that intentional content present inthe intelligible species that contributes to the production of an act ofthinking. 68 For example, my agent intellect abstracts from the sensory image ofcats the form felinity. That form is a real item present in my mind but it alsopossesses an implicit representational power, i.e. the power to make me thinkabout what it is to be a cat. An example may at least partially clarify whatScotus had in mind. A photo, say the photo of a cat, has certain physicalproperties, e.g. it is made of paper, ink, etc. To somebody looking at it,however, that photo also conveys a very specific representational content. It isthe photo of a cat. That the photo is ordinarily interpreted as the photo of a catis not due to a further physical property added to the photo. Rather, this is dueto that very physical object’s power to be interpreted as a representation of acat. This power to be interpreted as a representation of something else is whatScotus (borrowing the term probably from Henry of Ghent) called “objectivebeing” or “being present as something cognizable and represented” or assomething “shining through the intelligible species.” 69 The details of thisview—which is quite different from what Aquinas had held—are complicatedand controversial. Suffice it to say that the agent intellect produces a form, andby that production it also makes a certain content potentially present in thepossible intellect.The agent intellect’s production of a form representing a certainobject, however, is not sufficient for an act of thinking about that object tooccur. I may have as much information about cats as I can gather, but this isnot sufficient for me to perform an act of thinking about what it is to be a cat.In addition to the presence of the form felinity in my intellect, Scotus arguedthat a separate intervention of the intellect is necessary in order for an act of67 Ord. I, d. 3, p. 3, q. 1, n. 359, Vat. III, 216: “. . . intellectus agens est mere potentiaactiva . . . ergo potest habere actionem realem. Omnis actio realis habet aliquem terminusrealem.” See also Rep. I-A, d. 3, q. 4, n. 103, eds. Wolter and Bychkov, 212–213.68 Ord. I, d. 3, p. 3, q. 1, n. 386, Vat. III, 235: “Ad quartum dico quod intellectus nontantum patitur realiter ab obiecto reali, imprimente talem speciem realem, sed etiam ab illoobiecto ut relucet in specie patitur passione intentionali: et illa secunda passio est ‘receptiointellectionis’ – quae est ab intelligibili in quantum intelligibile, relucens in specie intelligibili – etillud ‘pati’ est ‘intelligere’ […].”69 See for example Quaest. super Meta. VII, q. 18, n. 44, OPh IV, 348; Ord. I, d. 36, q.unica, nn. 44–46, Vat. VI, 288–289; Ord. I, d. 3, p. 3, q. 1, n. 382, 386, Vat. III, 232, 235. PeterKing has argued that Scotus gradually became dissatisfied with the interpretation of mental orintentional existence as a kind of diminished existence. See King, “Scotus on Mental Content,”84–85. For Henry of Ghent’s use of the notion of objectively inhering in a cognizer, see SeeHenry of Ghent, Quodl. V, q. 14, f. 175rD: “[…] ut secundum hoc omnis cognitio sit (ed.: sic)secundum hoc quod cognitum secundum essentiam cogniti sit in cognoscente, et hoc non ut insubiecto cui inhaeret formaliter sed ut in concipiente obiective.”29

thinking about what it is to be a cat to occur. 70 Both the species and theintellect must act as efficient causes in order for an act of thinking about acertain thing to occur. Scotus argued that the species and the intellectcollaborate in the production of an act of thinking in a special way, which helikened to the collaboration of a man and a woman in the generation of achild. 71What should be stressed is Scotus’s clear distinction between twoactions involved in the production of an act of thinking, i.e. the act ofabstraction and the production of an act of thinking. 72 These are two distinctcausal processes, and more specifically two actions, which are identified bydistinct agents and distinct terms. The act of abstraction is caused by the agentintellect and the sensory image (the so-called “phantasm”). Its term is a mentalquality, i.e. the intelligible species. By contrast, the formation of an act ofthinking is caused by the intelligible species and the intellect after theabstraction of the species. The product of that second process is the act ofthinking proper. As I will show, Scotus argued that the act of thinking is amental quality, too.By clearly distinguishing between two actions involved in the act ofthinking and by claiming that the intellect must play the role of an efficientcause not just in the act of abstraction but also in the production of an act ofthinking, Scotus managed to lay the foundation for the distinction betweendispositional and occurrent knowledge. Only when the second process occursdoes an act of occurrent knowledge occur, i.e. do I actually think aboutsomething. When only the process of abstraction and reception of a formoccurs, some information is memorized and stored in the intellect, but noactual thought follows. This is the situation I experience when I know what itis to be a cat but I do not think about it.3.2. Acts of thinking as qualitiesScotus’s most characteristic insight, however, is not his distinctionbetween the two actions involved in the production of an act of thinking. As I70 Ord. I, d. 3, p. 3, q. 2, Vat. III, 245–330; Lect. I, d. 3, p. 3, q. 2–3, Vat. XVI, 349–395;Quodl., q. 15, nn. 7–9, Vivès XXVI, 137–141. It is clear that the act of thinking is distinct from theact of abstraction carried out by the agent intellect. It is an open question, however, whether theact of thinking itself is performed by the agent intellect, the possible intellect or both the agentand the possible intellect. Scotus considered each of these possibilities in Quodl., q. 15, nn. 13–20, Vivès XXVI, 141–153.71 Scotus argued that the intellect plays the main role as an efficient cause of an act ofthinking. He never held, however, that the intellect could produce an act of thinking without thecollaboration of the form of the object. See Ord. I, d. 3, p. 3, q. 3, Vat. III, 330–338; Quodl., q.15, n. 10, Vivès XXVI, 142–143.72 See above, note 66.30

have shown above, Aquinas had already distinguished the act of abstractionfrom the act of thinking proper. Admittedly, Aquinas had held that, once anact of abstraction is complete and once an intelligible species is present in theintellect in full actuality, an act of thinking necessarily follows, i.e. theintellect is necessarily activated and cannot refrain from actually thinkingabout something. By contrast, Scotus clearly distinguished between theintellect’s being made actual by the reception of a species and the intellect’sacting as an efficient cause in the production of an act of thinking. This is not,however, the main difference between Aquinas’s and Scotus’s accounts ofthinking. Rather, Scotus’s most typical claim was that both the act ofabstraction and the successive act carried out by the intellect and the speciestogether must be distinguished from the act of thinking. That second processresults in an act of thinking but is not itself an act of thinking. 73The distinction between an act of thinking and the process consistingin the joint action of the intellect and an intelligible species is a consequenceof Scotus’s general claim that acts of thinking are neither actions nor passions.Scotus’s argument for that claim was that actions and passions are necessarilyrelated to the term they bring about. For example, fire’s action of heating isnecessarily related to what it produces, e.g. a hot kettle. Similarly, a kettle’spassion of being heated is necessarily related to its term, i.e. that kettle’s beinghot. By definition, an action produces something and a passion entails theproduction of something. There can be no action or passion if a term is notproduced by that very action or passion. Scotus, however, remarked that anact of thinking produces nothing at all apart from itself. Rather, an act ofthinking is an ultimate end, which is carried out for the sake of itself and notfor the sake of anything else. It is true that sometimes something is producedby acts of thinking, i.e. a habit. For example, if I repeatedly think about what itis to be a cat, it becomes easy for me to entertain that act because I get used toperforming it. This, however, is an accidental result of my act of thinking. Acertain act of thinking is essentially the same act even though it does notproduce any habit (as with acts of thinking that are performed onlyoccationally.) In any case, it is clear that an act of thinking does not produceits object, because what I think about is presupposed, not produced, by myact of thinking about it. 7473 More precisely, an act of thinking is what Scotus calls the “formal term” of theprocess carried out by the intellect and the species together. The proper term of that process is thewhole constituted by the intellect thinking about something or an individual person thinkingabout something. See Rep. I-A, d. 3, q. 6, nn. 183–184, eds. Wolter and Bychkov, 239.74 Rep. I-A, d. 3, q. 6, n. 171, eds. Wolter and Bychkov, 235–236: “Item, de actione etpassione probatur idem [scil., quod intellectio non est actio vel passio]: nam actio et passionecessario sunt alicuius termini accipientis esse per actionem et passionem; quia non est31

So what sort of thing is an act of thinking, if it is neither an action nora passion? Assuming that all things belong to one of the ten Aristoteliancategories, Scotus proceeded by process of elimination. 75 Apart from actionsand passions, he held that there are only two plausible candidates. First, anact of thinking may be a relation. Second, an act of thinking may be a quality.Scotus had three arguments to demonstrate that in an act of thinkingthere is a non-relative feature that cannot be reduced to a relation, and that, asa consequence, an act of thinking is not a relation.Scotus’s first argument was based on the view that an act of thinkingis the ultimate perfection of a human being. According to Scotus, however,the ultimate perfection of a human being could not be a relation. Therefore,an act of thinking is not a relation. The claim that an act of thinking is theultimate perfection of a human being was commonly agreed on. The basicidea was that the activity of thinking is what a human being is made for andwhat satisfies our deepest needs. We were born in order to think. This isconfirmed by the fact that human nature will be perfected in the final unionwith God in the beatific vision, which is (at least partially) an intellectual act,and thus may be considered as a very special act of thinking. 76 Strangelyenough, Scotus did not spend much time to support the minor premise of thisargument, according to which the ultimate perfection of a human beingcannot be a relative item. Presumably, Scotus’s point was based on the remarkthat a relative item is identified by its term and is consequently essentiallydependent on that term’s existence. For example, the relation of paternity isgrounded in a father and directed at a child. If no child is generated, there isno relation of paternity. But then, if a human being’s ultimate perfection werea relation, a human being’s ultimate perfection would be essentiallydependent on something else, i.e. its term. Thus, the ultimate perfection of ahuman being would not be ultimate, because it would in turn depend on theintelligibile quod sit calefactio et quod nullius ulterioris termini, scilicet quod nihil accipiatcalorem per eam; sed operationes sunt termini ultimi quibus nihil ulterius accipit esse, quia suntfines, I Ethicorum et IX Metaphysicae. Obiectum vero operationis ad quod terminatur operationon accipit esse per eam, sed praesupponitur operationi, quia sunt fines operantis, ut dictum est;ergo etc.” See also Ord., d. 27, q. 1–3, n. 55, Vat. VI, 86: “[…] intellectio non est actio productivaalicuius termini: tunc enim incompossibile esset intelligere eam esse, et non esse termini, sicutincompossibile est intelligere calefactionem esse et non esse calorem ad quem sit calefaction.Non est autem impossibile intelligere intellectionem in se, non intelligendo quod sit alicuiustermini ut producti per ipsam.”75 Quodl. q. 13, n. 25, Vivès XXV, 570–571; Rep. I-A, q. 6, nn. 169–237, eds. Wolterand Bychkov, 234–237.76 See for example Aquinas, Sent. I, d. 35, q. 1, a. 5, ad 4; Sent IV, d. 49, q. 3, a. 2; DePot., q. 5, a. 5, ad 14; De malo, q. 1, a. 5; ST I-II, q. 3, a. 2; ST I-II, q. 49, a. 3, ad 1.32

existence of its term. Scotus held that this argument applied to actions andpassions as well. 77Scotus’s second and third arguments are possibly more interesting.Scotus’s second argument that in any act of thinking there is anirreducible non-relative feature is based on the view that two things becomenewly related to each other if and only if a new non-relative item is acquiredby either or both of them. For example, a chair becomes similar in color to awall only if the chair is colored like the wall or the wall is colored like thechair or both the chair and the wall are colored in the same way. Now, an actof thinking can occur without the reception of a new form either in theintellect or in the thing thought about. For example, suppose that I alreadyknow what it is to be a cat; I do not have to acquire any new information inorder to actually think about what it is to be a cat. My intellect must acquire anew form only when it is in essential potency with respect to the knowledgeof what it is to be a cat, i.e. when I am ignorant of what it is to be a cat. Bycontrast, when I know what it is to be a cat but I do not think about cats, myintellect is in a state of accidental potency, i.e. it can perform an act ofthinking about what it is to be a cat without acquiring any new form.Similarly, cats do not acquire a new form when I think about what it is to be acat. Since a new act of thinking can be brought about without the acquisitionof a new form in the intellect, it follows that acts of thinking are not relations:The main conclusion [namely, that in all intellection and, in general,for any activity we are speaking of here, there is some non-relative entity] isproved secondarily in this fashion: A relation proper is not new unless therebe in either the subject or the term some prior absolute entity that is new. Butan activity can be new without any other prior absolute being present ineither the operator himself or in the term of the activity. Therefore the activityis not precisely a relation proper. Hence [it is something non-relative]… Proofof the first part of the minor: A subject which passes from accidental potencyto act does not receive a new form prior to the activity itself; otherwise itwould have been in essential, not accidental, potency. The second part of theminor is manifest, for it is obvious that something visible does not acquireanything absolute by the fact that it is actually seen; neither does anintelligible object, and the same is true of other activities.7877 Scotus, Quodl., q. 13, nn. 3–4, Vivès XXV, 508–509; Rep. I-A, d. 3, q. 6, n. 169, eds.Wolter and Bychkov, 234–235.78 Scotus, Quodl., q. 13, n. 4, Vivès XXV, 509: “Secundo probatur conclusio principalis[scil., quod in omni intellectione et generaliter operatione quacumque de qua loquimur, estaliqua entitas absoluta] sic. Relatio proprie dicta non est nova sine novitate alicuius absolutiprioris, et hoc in subiecto vel in termino. Operatio autem potest esse nova sine novitatecuiuscumque alterius prioris absoluti in ipso operante, sine etiam cuiuscumque alterius absolutinovitate in termino. Igitur operatio non est praecise relatio proprie accipiendo relationem. Igituretc. […] Minor probatur quantum ad primam partem, quia illud quod exit de potentia accidentali33

This is a remarkable argument. It is based on the key fact that thepassage from dispositional to occurrent knowledge takes place without theacquisition of any new form in the intellect. The apparent technicality ofScotus’s point should not obscure the novelty of his position. Scotus wasfocusing on the weak point of the Aristotelian account of thinking as a changeor process. As scholars of Aristotle have noticed, the passage fromdispositional to occurrent knowledge (which I labeled “the problem ofoccurrent thought”) constituted the breaking point of the view that thinking isa change since at least Aristotle’s times. As I have showed above, Aquinas hadstruggled to find a solution to this problem. He introduced the suspect notionof a species being present in the intellect in incomplete actuality just for thatreason. By contrast, Scotus took the peculiar character of the passage fromdispositional to occurrent knowledge (a “change” without the acquisition of anew form) as the starting point to investigate the nature of an act of thinking.Scotus’s third argument in support of his claim that an act of thinkingis not a relation was based on the fact that an act of thinking is itself related toits object. For example, my act of thinking about what it is to be a cat isrelated to what it is to be a cat, i.e. (according to Scotus) the essence of cats.Now it was a common assumption that only a non-relative item can be relatedto something else, because only a non-relative item can play the role of thefoundation of a relation. For example, the relation of paternity holdingbetween a father and his child is grounded in a non-relative feature pertainingto the father, i.e., presumably, his power to procreate. The father’s power toprocreate must be interpreted as a non-relative item in order to exclude thepossibility of an infinite regress. Acts of thinking, however, are related to theirobjects. It follows that they are not relations. 79Scotus’s arguments that acts of thinking are neither relations noractions or passions are remarkable especially because they reveal hiscommitment to two claims that Aquinas had been forced to reject. In hisargument that acts of thinking are not actions or passions, Scotus assumed thatacts of thinking do not produce anything (unless, accidentally, a habit). Thisassumption is intuitively uncontroversial. Unlike actions such as building orad actum non recipit aliquam formam novam priorem ipsa operatione, quia tunc non fuisset priusin potentia accidentali sed essentiali. Secunda pars minoris est manifesta. Patet enim quod nihilasbolutum advenit visibili quando videtur actu nec intelligibili quando intelligitur actu, etconsimiliter de aliis.” The English translation is taken, with a few modifications, from John DunsScotus, God and Creatures. The Quodlibetal Questions, translated with an Introduction, Notesand Glossary by F. Alluntis and A. B. Wolter (Princeton and London: Princeton University Press,1975), 286–287.79 Quodl., q. 13, n. 5, Vivès XXV, 509; Rep. I-A, d. 3, q. 6, n. 170, eds. Wolter andBychkov, 235.34

painting, acts of thinking do not issue in a result separate from their veryexercise. Aquinas, however, had rejected precisely that claim in his secondaccount of acts of thinking as self-contained actions with internal termsproduced by those very acts. Similarly, in his third argument that acts ofthinking are not relations, Scotus assumed that acts of thinking areimmediately related to their objects. Again, this assumption is intuitivelynoncontroversial. My act of thinking about what it is to be a cat is about whatit is to be a cat, so it is related to it. As I have shown, however, Aquinas hadrejected precisely that claim in both of his accounts of thinking as a selfcontainedaction.Scotus’s general strategy can be easily perceived behind thetechnicality of his arguments. Aquinas’s commitment to the view that acts ofthinking are actions forced him to embrace some implausible conclusions, i.e.that acts of thinking are not related to their objects or that they produce theirown terms. By contrast, Scotus took the implausibility of these conclusions asevidence that Aquinas’s approach was wrong-headed. In order to avoid thoseimplausible positions, the claim that acts of thinking are relative items andmore specifically that they are actions should be rejected.Since acts of thinking are neither relations nor actions or passions,Scotus concluded that they are qualities. Specifically, he argued that they arein the first of the four species of qualities Aristotle had distinguished in theeighth chapter of his Categories. Since Aristotle sorted out the qualitiesbelonging to the first species into habits such as virtues and more fleetingconditions such as heat, cold, disease and health, it seems likely that Scotusregarded acts of thinking as those fleeting dispositions (diatheseis, affectiones),which can be easily acquired or lost. 80Scotus seems to have been aware of the novelty of this claim.According to Aquinas and to the standard Aristotelian theory, acts of thinkingare actions similar to fire’s action of heating. By contrast, Scotus likened theact of thinking to heat, not to the action of heating or the passion of beingheated. This position clashed with the intuition that to think is something that Iperform, i.e. something I do. By contrast, according to Scotus what I performis the action that results in an act of thinking. By itself, however, an act of80 Rep. I-A, d. 3, q. 6, nn. 175–176, eds. Wolter and Bychkov, 237: “Restat ergonecessario concedere quod istae operationes sint qualitates, cum non sint nihil nec in aliquogenere, sicut superius est probatum. Sed non sunt de secunda specie qualitatis, quia non suntnaturalis potentia vel impotentia; nec de tertia vel quarta specie, quia istae tantum conveniuntcorporalibus […]. Relinquitur ergo quod operationes sunt in prima specie qualitatis, etuniversaliter omnis perfectio naturae spiritualis, si non sit substantia eius—sive sit in fieri, sive sitpermanens et in facto esse—est in prima specie qualitatis.” See also Quodl., q. 13, n. 15, VivèsXXV, 570–571. For Aristotle’s text, see Cat. 8, 8b26–9a4.35

thinking is not something I perform, but something I have, just as I have thequality heat or the quality cold. This claim is striking, because at first sightthere seems to be little in common between a quality such as heat or cold andan act of thinking, whereas there seems to be much in common between anaction such as heating and cooling and an act of thinking.Scotus admitted that acts of thinking belong to a special sort ofqualities called “activities” (operationes). In calling acts of thinking“activities,” Scotus was just following Aristotle and was in agreement withAquinas. There is, however, a fundamental difference between Scotus andAquinas. As I have indicated above, Aquinas regarded activities as genuineactions, albeit self-contained and not transitive. Scotus, by contrast, held thatactivities are not actions but qualities. He recognized, however, that activitiesmight be confused with actions such as heating, on the one hand, and withsome other impermanent qualities such as light, on the other hand. In order toclafity this issue, Scotus listed three conditions that should be taken intoaccount when identifying something as an action, an impermanent quality oran activity.The first condition is that of being impermanent or in fieri, i.e. ofexisting only as long as an agent carries out its action. For example, the actionof heating exists only as long as fire carries it out. Also, light exists only aslong as a source of a light source performs the action of illuminating.Similarly, an act of thinking exists only as long as its causes (ordinarily, anintellect and an intelligible species) carry out their action of producing it. Assoon as the agent ceases to perform its action, the action of heating, thequality of being illuminated and the act of thinking cease to exist.The second condition is that of having a term about which (circaquem) the action or quality occurs. This term is the object of the action orquality. For example, fire’s act of heating is directed at or about a kettle.Similarly, my act of thinking about what it is to be a cat is directed at or aboutwhat it is to be a cat.The third condition is that of having a term towards which (ad quem)the action is directed. This term is produced by that action. For example, fire’sact of heating produced a hot kettle.Only items belonging to the category of action satisfy all threeconditions. Actions are impermanent or in fieri, have a term about which theyare performed and produce something. By contrast, impermanent qualitiessuch as light only satisfy the first condition. Light exists only as long as a lightsource illuminates. But light does not necessarily require a subject in which tobe received and light produces nothing. Finally, acts of thinking satisfy boththe first and the second condition, but not the third. First, acts of thinking36

exists only as long as the intellect and a species in the intellect perform theirconcurrent action of producing such an act. When either I have noinformation about cats or I have completely forgotten everything about cats, Ido not and cannot think about what it is to be a cat. Also, when I know whatit is to be a cat but I do not turn my intellect towards that information, no actof thinking about what it is to be a cat occurs. Second, just like actions, acts ofthinking are necessarily about an object. Unlike actions, however, activitiessuch as acts of thinking produce nothing (unless, accidentally, a habit). 81Admittedly, Aristotle had called activities such as thinking selfcontainedactions and he contrasted them to transitive actions such asbuilding and heating. Scotus, however, stated that this should not beinterpreted as a distinction between two kinds of actions (self-contained andtransitive, respectively). Rather, Aristotle’s claim should be regarded as adistinction between two senses of the word “action.” In the first sense, theword “action” refers to genuine items belonging to the category of action,such as building and heating. In the second sense, the word “action” refers toactivities such as thinking and perceiving, which, although they may beconfused with actions, are nevertheless items in the category of quality. Selfcontainedactions, accordingly, are qualities, not actions. 823.3. Scotus on the intentionality of acts of thinkingStill, it may be suspected that Scotus’s claim that acts of thinking arenot actions but qualities amounts to little more than a local disagreement withAquinas and other thinkers concerning a negligible issue. That this is not thecase, however, may be appreciated when the issue of the intentionality of actsof thinking is taken into account.Since acts of thinking are in themselves non-relative items, Scotuscould contend that they are directly related to their objects. Remember thatthis is what Aquinas could not claim. According to Aquinas, acts of thinkingare actions that either are not related to their objects or are directly related tothe concepts they produced but not to the external things they are supposed tobe about. This was a consequence of Aquinas’s view that acts of thinking areself-contained actions. A self-contained action is directed at either nothingapart from itself (in Aquinas’s first account) or its own product (in Aquinas’s81 Quodl. q. 13, n. 27, Vivès XXV, 575; Rep. I-A, d. 3, q. 6, n. 191, eds. Wolter andBychkov, 241–242. For a previous attempt to distinguish activities from actions and impermanentqualities, see Ord. I, d. 3, p. 3, q. 4, nn. 601–603, Vat. III, 354–356.82 Quodl. q. 13, n. 26, Vivès XXV, 571, and especially n. 27, Vivès XXV, 575: “Et itaista distinctio actionis sic intellecta in transeuntem et immanentem non est generis in species, sedvocis in significationes. Nam actio transiens est vera actio de genere actionis, actio immanens estqualitas, sed aequivoce dicitur actio propter conditiones praedictas.”37

second account). In neither case is there any room for a self-contained actionto be directed at something external. As a consequence, the link between anact of thinking and its object was at best indirect, according to Aquinas. Thekey feature that explained intentionality was not something pertaining to anact of thinking. Rather, intentionality was explained by the form whosepresence in the intellect triggered an act of thinking. In other words, theintelligible species and the agent intellect’s act of abstraction were responsiblefor intentionality. Thus, acts of thinking did not play any role in accounting forintentionality. For example, my act of thinking about what it is to be a cat isabout the essence of cats, according to Aquinas, because it is produced by theintellect when the form felinity is abstracted by the agent intellect andreceived in the possible intellect. Consequently, Aquinas held thatintentionality is explained by the causal story linking an object to the intellectby way of form abstraction and form reception. That causal relation goes fromthe extramental thing to the intellect, not the other way around.By contrast, Scotus linked acts of thinking directly to their objects, i.e.to extramental things. He could achieve that result because he regarded actsof thinking as qualities, i.e. non-relative items, which can play the role ofdirect foundations for relations directed at extramental things. 83But there is more. Not only did Scotus hold that the intentionality ofacts of thinking is accounted for by a feature pertaining to those actsthemselves, i.e. by their being related to their objects. At least in a couple ofpassages, Scotus even argued that the intentionality of acts of thinking isexplained only by their relation to their objects. Specifically, the presence of acertain form in the intellect prior to an act of thinking does not play anyessential role in explaining the intentionality of that act. The presence of acertain species in my intellect is neither a necessary nor a sufficient conditionfor a certain act’s being about a certain thing. For example, my act of thinkingabout what it is a cat is about the essence of cats because it is directly relatedto the essence of cats, not because my intellect has previously received theform felinity. Scotus admitted that in most cases my intellect must havereceived such a form prior to the actual occurrence of a thought. The priorreception of a form, however, is necessary only in order to account for theuniversality of a thought (e.g. for the fact that I think about what it is to be a83 Rep. I-A, d. 3, q. 6, n. 170, eds. Wolter and Bychkov, 235: “Minor [scil., quodintellectio et omnis operatio est ad aliquid] patet per Philosophum, V Metaphysicae, dicentemoperationem [pro: scientiam?] dici relative ad obiectum, ut mensuratum ad mensuram, quiaobiectum est mensura operationis; unde si scientia dicatur ad aliquid, multo magis operatio etactus scientiae quae immediatius respiciunt obiectum quam habitus; immo habitus non respicitobiectum nisi mediante actu.” Scotus analyzed the act of thinking’s role as the foundation of arelation directed at its object in Quodl., q. 13, nn. 6–7 and nn. 11–14, Vivès XXV, 525–541.38

cat rather than about what it is to be this or that individual cat). The presenceof that form, however, does not play an essential role in explaining why myact is about what it is about.Scotus demonstrated this point by a straightforward argument. Sinceacts of thinking are non-relative items, they can be created immediately byGod. Thus, God can create my act of thinking about what it is a cat eventhough I have no form felinity in my intellect. Nevertheless, my act of thinkingwould still be about cats, not about God, even if God and not cats were thecause of my act of thinking about cats. 84The upshot of all this is that according to Scotus intentionality is arelation holding between an act of thinking and its object, which cannot beaccounted for by the causal story linking the object to the intellect but shouldrather be assumed as a primitive relation linking an act of thinking to itsobject.So what sort of relation is intentionality, according to Scotus? Here itis necessary to distinguish two separate issues. First, one must consider thenature of the relation linking an act of thinking to its object. Second, one mustfocus on the relationship between the intentional relation itself and an act ofthinking.Concerning the first issue, Scotus was willing to consider theintentional relation holding between an act of thinking and its object as arelation of likeness (similitudo). Unlike Aquinas, however, he stressed thatsuch a likeness cannot be accounted for as the sharing of a common form. Anact of thinking is a likeness of its object not because it has the same form of itsobject but because it is an “imitation” (imitatio) of its object, just as somethingmodeled against a certain idea is an imitation of that idea. 85 Admittedly, thisamounts to little more than saying that the intentional relation holdingbetween an act of thinking and its object is a sui generis relation, whichshould be assumed as primitive. Acts of thinking are about their objects justbecause of the kind of things they are. Scotus also stressed that such a relationcannot be reduced to any the four Aristotelian cause. An object is not theformal, material, efficient or final cause of the act of thinking that is about thatobject. 86 Consequently, intentionality must be assumed as a primitive relationthat cannot be explained in terms of the causal relations considered within theframework of natural philosophy.84 Ord. I, d. 3, p. 3, q. 2, nn. 477–479, Vat. III, 285–286. See also Lect. I, d. 3, p. 3, n.392, Vat. XVI, 377.85 Quodl., q. 13, n. 12, Vivès XXV, 526.86 Aquinas maintained that the object is the final cause of the act of thinking. Seeabove, note 54.39

Scotus, however, attempted to give a more positive description of theintentional relation holding between an act of thinking and its object. Aristotlehad already mentioned a class of relations involving “the measure and themeasured” 87 . He had illustrated that class of relations by making reference tothe relation holding between something known (playing the role of themeasure) and knowledge (playing the role of the measured). 88 The idea wasthat, if an object o acquires a relation R to a knower k, no real change occursin o. This implies that the relation R holding between o and k is not real. Theexplanation for this is that the relation R is not founded on any real feature ofo that o lacked when it was not related to k by R and that o acquired when itbecame related to k by R. Thus, when I know a certain thing, that thing doesnot acquire any real feature and does not undergo any real change. Bycontrast, if a knower k acquires a relation R i to an object o, some real changeoccurs in o. This implies that the relation R i holding between k and o is real.The explanation for this is that the relation R i is founded on a real feature of k,which k lacked when it was not related to o by R i and acquired when itbecame related to o by R i .These relations were called “non-mutual,” because one of them is realand the other one is not. By contrast, mutual relations are either both real orboth non-real. For example, the relation holding between a father and a son ismutual, because there is a corresponding real relation holding between theson and the father.Aristotle had developed this framework to account for the relationholding between dispositional knowledge and its objects. Scotus applied it tothe relation holding between occurrent knowledge and its objects, i.e. acts ofthinking and what they are about. When I think about something, no realfeature is acquired by the object of my act of thinking; by contrast, I acquire areal feature, i.e. an act of thinking, which is a quality present in the mind butnevertheless real. I possess that mental quality only as long as I actually thinkabout a certain thing. Thus, to think makes a difference to me but not to what Iam thinking about. The intentional relation linking my act of thinking to what Iam thinking about is a non-mutual relation of the same kind as the relationlinking knowledge to what is known and what is measured to what measuresit.87 Quodl., q. 13, nn. 11–12 (Vivès XXV, 525–526). In that passage, Scotus distinguishedthe measure/measured relation from another kind of relation, which he called “relatioattingentiae.” He clarified, however, that the relatio attingentiae pertains only to acts of intuitivecognition. See ibid., n. 14 (Vivès XXV, 540). Since I focus on abstractive cognition, I do not takethe relatio attingentiae into account.88 Meta. V, 15, 1021a26–b3; Meta. X, 1, 1053a31–b3; Cat. 7, 6b1–6. See Henninger,Relations, 6–8.40

Concerning the second issue, as I have said, Scotus held that theintentional relation holding between an act of thinking and its object is arelation founded in an act of thinking and directed at its object as its term.Since acts of thinking are non-relative items, the intentional relation holdingbetween an act and its object cannot be part of the essence of an act ofthinking. Thus, the link between an act of thinking and its object is not anessential property of an act of thinking. As a consequence, if an act of thinkingis an item belonging to just one category (as it is likely to be), it follows that anact of thinking and its relation to its object are two distinct items belonging totwo distinct categories:From this it follows that either the act of thinking is not somethingper se one pertaining to a single genus, or else it does not include per se thetwo elements which were proved to concur in it [scil., an absolute and arelative element]. But the first article […] seems to establish that the absoluteelement is included essentially. Consequently, the act does not appear to beessentially relative in the sense of including the relation per se.89Accordingly, Scotus held that, if we were able to define acts ofthinking in precise terms, there would be no need to include in theirdefinitions any mention of their objects. Thus, it would be possible to definemy act of thinking about what it is to be a cat without mentioning cats at all.As a matter of fact, however, this is not the case. We are not able to provideprecise definitions of acts of thinking, and as a consequence we end upidentifying acts of thinking thanks to their objects. 90Scotus, however, stated that the intentional relation holding betweenan act of thinking and its object, even though it is not part of the essence ofthat act of thinking, pertains to that act of thinking necessarily. Thus, it isimpossible for a certain act of thinking to exist and not to be about the objectis it about. For example, my act of thinking about what it is to be a cat isnecessarily about the essence of cats, even though at least in principle it maybe defined without ever mentioning the essence of cats. The relation betweenan act of thinking and its object can be described as an asymmetric relation of89 Quodl., q. 13, n. 24, Vivès XXV, 569: “Ex his sequitur quod actus cognoscendi velnon est aliquid per se unum unius generis vel non per se includit illa duo, quae probata suntconcurrere [scil., aliquid absolutum et relatio]. Videtur autem probatum in primo articulo quodessentialiter includat absolutum […]. Igitur videtur quod actus talis non sit essentialiter relativus,sicut per se includens relationem.” The English translation is taken, with some modifications, fromJohn Duns Scotus, God and Creatures, trans. Alluntis and Wolter, 303–304.90 Quodl., q. 13, n. 30, Vivès XXV, 577. Scotus also considered an alternative view,according to which the definition of an act of thinking must include a reference to its object as tosomething extrinsic but nevertheless necessary. See ibid., n. 31, Vivès XXV, 577–578.41

mensurability (i.e., the act of thinking is measured by its object) ordependence (i.e. the act of thinking depends on its object). 91The claim that some feature may pertain to a certain subjectnecessarily but not essentially may sound surprising. Nevertheless, it was astandard Aristotelian view. For example, properties such as the ability to laughwere thought to pertain necessarily but not essentially to human beings. If youare a human being, necessarily you are able to laugh. But if I have to definewhat a human being is, I do not have to include the ability to laugh among theessential features of human beings. Just as the ability to laugh in humanbeings, the intentional relation to an object is not part of what an act ofthinking is, but it necessarily pertains to it. In this respect, the relation betweenan act of thinking and its object seems to be akin to the relation between acreature and God. Even though the relation between a creature and God is notpart of the essence of a creature, no creature could exist if it did not dependon God. Therefore, that dependence relation pertains to a creature necessarilybut not essentially. Similarly, the relation to an object is not part of theessence of an act of thinking is. Without that measure or dependence relation,however, no act of thinking could exist. Therefore, the relation to a certainobject pertains to a certain act of thinking necessarily but not essentially. 92***Scotus’s answer to the three questions I have mentioned at thebeginning of this paper should now be clear.(1) An act of thinking is a quality. It is, admittedly, a special kind, i.e.an impermanent quality that requires the constant action of its causes to bekept into existence. And it is a quality that is about something, i.e. its object.Nevertheless, a quality it is, not an action. Thus, an act of thinking is notsomething that I do but something that I have. In the current order of things,my intellect and a form present in my intellect do perform the process thatresults in an act of thinking. God, however, may bypass both my intellect andthe form present in my intellect and create an act of thinking directly in myintellect.91 Quodl., q. 13, n. 13, Vivès XXV, 539–540. A further complication is that the objectof an act of abstractive cognition does not have to exist. For example, I may be thinking aboutwhat it is to be a cat even though cats may be extinct. For that reason, Scotus described therelation between an act of thinking and its object as a real potential relation.92 On Scotus’s position on the relation between creatures and God, see Scotus, Ord. II,d. 1, q. 4–5, nn. 260–75, Vat. VII, 128–36; Lect. II, d. I, q. 4–5, nn. 238–58, Vat. XVIII, 80–88. SeeHenninger, Relations, 78–85. In Scotus’s jargon, it may perhaps be said that an act of thinking isreally identical to but formally distinct from the relation to its object.42

(2) In the current order of things, the presence of a form in theintellect and the intellect’s own action as an efficient cause are separatelynecessary and jointly sufficient for an act of thinking to occur. Exceptionally,however, God can bypass both the intellect and the form and act as the solecause of an act of thinking.(3) The intentionality of an act of thinking is accounted for by aspecial relation founded on the act of thinking itself and linking it directly toits object. Such an intentional relation between an act of thinking and itsobject cannot be reduced to any of the Aristotelian causes. Rather, it shouldbe assumed as primitive.Scotus’s key move in his account of thinking was his insight that tothink is neither to do something nor to be related to an object. Rather, it is amental quality, i.e. a non-permanent condition present in the intellect. Bytaking that step, he gave up the idea that the occurrence of thoughts can beexplained as a kind of natural change or process and the cognate view that theintentionality of an act of thinking is a phenomenon akin to the production ofnatural effects. 9393 I presented a shorter version of this paper at the Franciscan University, Steubenvillein 2008. I am thankful to the audience for their questions and criticisms. I discussed some of theseissues with Marilyn McCord Adams, Susan Brower-Toland, Russell Friedman, Timothy Noone,Martin Pickavé and Cecilia Trifogli. Gyula Klima commented on a previous version of this paperand was a constant source of help in the course of many conversations on these and similartopics. I wish to thank them all.43