Zabarella’s De Mente Agente, Chapter 3

Main topics covered: the activity of the agent intellect, the role of the passive intellect in relation to the agent intellect, Simplicius’ account of the role of the agent intellect in relation to the passive intellect, refutation of Simplicius’ view, refutation of Jean of Jandun’s view, the analogy between sight and understanding, the Aristotelian theory of vision, light as a perfecting form, agency vs.  perfecting form, refutation of Aquinas and John Baconthorpe on the role of the agent intellect

Chapter 3 : The Refutation of the Aforesaid Opinions

Dictarum  opinionum Confutatio Cap. III

Nos vero aliorum errores patefaciendo simul ipsam rei veritatem iuxta Aristot. mentem declarabimus.


In primis a veritate prorsus aberrant illi, qui dicunt intellectum agentem agere in phantasmata, quoniam, ut modo alios considerasse dicebamus, Aristot. intellectum agentem invenit propter intellectum patibilem, & ut in eum ageret tanquam patientem.



Sed obstare nobis videntur verba Aristot. in contextu 18 quando intellectum agentem cum lumine comparat, & significat ipsum agere in phantasmata: iis tamen verbis  bene intellectis tolletur omnis difficultas, & ipsa rei veritas manifesta fiet. Sciendum igitur est, quando dicimus aliquid facere de tali potestate tale actu verbum illud (facere) ambiguum esse, & posse intelligi duobus modis, potest enim facere ut forma, potest etiam facere ut agens, forma enim humana adveniens materiae, facit de homine potestate hominem in actu,



neque ob id est agens, quia facit hominem ad modum formae, non ad modum agentis, homo vero generans alterum hominem dicitur facere hominem tanquam agens: differentia igitur est in hoc constituta, quod ignis generat alterum ignem & facit de igne potestate ignem actu, producendo in illa materia alteram  formam ignis sibi similem; illa vero altera forma producta facit de igne potestate ignem actu, non tamen  producendo aliam formam, sed ut forma ipsa quia non id facit ut agens: iungitur enim ipsi rei; at agens generans externum est, neque cum materia coniungitur.

Quando igitur Arist. dicit intellectum agentem facere phantasmata actu intelligibilia de intelligibilibus potestate, non ob id declarat rationem agentis, quia non id praestat ut agens, sed ut forma; iungitur enim phantasmatibus lumen intellectus agentis tanquam forma, qua redduntur motiva, & actu intelligibilia, sicuti lumen iungitur colori tanquam forma, & perfectio, qua redditur actu visibilis, & actu motivus visus,

neque dicitur lumen esse agens respectu colorum; quia nihil in eis producit ut agens, sed eis iungitur ut forma, per quam totum hoc coniunctum, color illuminatus, constituitur in esse obiectivo, & fit actu motivum visus:


hoc significavit Arist. in eo ipso loco, dum dixit intellectum agente facere omnia tanquam habitum quendam; habitus enim formam denotat, non causam effecticem, quia efficiens est a patiente disiunctum, forma vero iungitur materiae recipienti, & habitus rei habenti habitum; sic lumen coloribus haeret ut forma, & perfectio neque ad eos se habet ut agens ad patiens.





Non est igitur verum id, quod prima secta dicit, intellectum agentem agere in phantasmata, & argumentum eorum nullius roboris est. Decepti etiam sunt illi qui putarunt intellectum agentem agere in intellectum patientem tanquam agens distiunctum a phantasmatibus, quod extra phantasmata agendo perficiat intellectum patientem, & ipsi tribuat intellectionem; hoc enim dato, sequeretur intellectum patientem  posse etiam sine phantasmatibus intelligere, nempe sumendo congnitionem immediate a solo agente;


id tamen Aristot. adversatur, qui in context. 30 & 39 lib. 3 de Anima aperte dicit, fieri nunquam posse ut intellectus intelligat, nisi phantasma aliquod speculando: quare secundum Arist. omnis nostra intellectio fit ex motione facta a phantasmatibus. Immo non solum falsum est id, quod dicunt, intellectum agentem tribuere patienti suam cognitionem, sed neque ea ratione, qua est agens, est intelligens; quamvis enim necessario consequatur ut sit mens aliqua, & actu intelligens, tamen ea ratione, qua est agens, nihil formaliter intelligit, sed solum effective, quatenus in homine intellectionem producit:



quomodo autem id faciat, postea declarabimus, & ostendemus intellectum agentem esse quidem semper intelligentem, agere tamen non ut intelligentem, sed ut intelligibilem:



falsum id quoque est, quod Gendavensis dicit, intellectum agentem in intellectu patiente producere actum intelligendi; postea enim ostendimus intellectum patibilem sufficientem sibi esse ad promendam intellectionem sine ope intellectus agentis. Quocunque igitur modo dicatur intellectum patibilem pati ab intellectu agente, tanquam ad agente distinctio a phantasmatibus, & tanquam a cognoscente, falsum est & ab Arist. alienum. Quum autem utraque haec secta erraverit, erraverit etiam tertia, quae unum cum altero errorem coniunxit, ut considerantibus manifestum est.



But we, by bringing to light the errors of others, shall at the same time make clear the very truth of the matter according to the mind of Aristotle.
Against Aquinas and John Baconthorpe
First of all, they wander entirely astray from the truth who say that the actualizing intellect acts upon images, since, in the way we have said others considered it, Aristotle devised the agent intellect in relation to the passive intellect so that it might, in turn, act upon it as upon something playing a passive role.
The Solution of the Argument

But Aristotle’s words in contextu 18 seem to disagree with to ours when he compares the agent intellect to a light and indicates that it acts upon images. However, all difficulty is removed and the real truth of the matter becomes evident when these words are properly understood. It should be recognized, therefore, that when we say that something makes of whatever is such that it is in a state of potentiality, to be such that it is in a state of actuality, that word “makes” is ambiguous and can be understood in two ways: for it can be understood (1) as form and can also be understood (2) as an agent, since the human form, arriving in matter, “makes” a potential human an actual human and not because it is an agent (since it “makes” a human being according to the mode of form, and not according to the mode of agency), whereas a human, creating another human is said to “make” a human as an agent.  The difference consists in this: that fire generates another fire and makes of the potential for fire an actual fire, by producing in the matter another form of fire similar to it; however, that other form which was produced, brings about an actual fire from a potential fire, not by producing another form, but as form itself, since it does not bring it about as an agent: for it is brought together with the aforesaid matter in question-but a generating agent is external and does not become conjoined with matter.

Therefore, when Aristotle says that the agent intellect “makes” images actually intelligible from a state of potential intelligibility, he should not be taken as discussing the nature of an agent, because he does not present it as an agent, but as form: for the light of the agent intellect is joined to images as a form, whereby they are set in motion and are made actually intelligible, just as light is conjoined with color as a form and a perfection , whereby it is rendered actually visible, and vision is actually moved [See note 1].  Nor is light said to be an agent with respect to colors, since it produces nothing in them as an agent, but is joined to them as a form whereby the whole is conjoined. Therefore, when color is illuminated, a phantasm begins to exist as an object, and the sense of sight comes to be actually moved.

Aristotle indicated this in the same place where he said that the agent intellect makes all things in the way a “disposition” does [see note 2]: for a disposition indicates a form, not an efficient cause [see note 3], since being a motive cause of change is outside the role of what is essentially passive; however, a form is joined to the matter of the recipient and a disposition is held by what has it: thus, light adheres to colors as a form and a fulfillment (perfectio) and not to them in the way an agent is related to what is essentially passive.

Refutation of Simplicius and of Others

Therefore, it is not true that, as the first sect holds, the agent intellect acts upon images and their argument lacks any strength. They were also deceived who thought that the agent intellect acts upon the passive intellect such that the agent is not conjoined with images, since it brings to fulfillment and imparts intellectual activity to the intellect which is essentially passive, without acting upon images. By having said this, it follows that the essentially passive intellect can think the forms in images even without images, that is, by taking cognition immediately from the agent alone.

But this conflicts with Aristotle’s view, who in contexts 30 and 39 of the De Anima clearly says it can never happen  that the intellect might think without attending to an image. For that reason, according to Aristotle, our intellect becomes all things from the motion created by images.  Indeed, what they say is not only false, when they say that the agent intellect imparts its own cognitive activity to the the passive intellect, but neither, by that reasoning, considering the activity of the agent, is it able to think. For even though it necessarily follows that it is a mind and actually able to think, nevertheless, by that reasoning accoring to which it is an agent, it understands nothing formally, but only as an effect of something else, to the extent that it produces intellectual activity in humans.

But we will explain how it does so in what follows, and will show that the agent intellect is, in fact, always understanding, however not as  understanding, but as intelligible


[Reply to Jean of Jandun (Gandavensis)]

What Jean of Jandun claims is also false, that the agent intellect produces the act of understanding in the passive intellect: for we will later show the passive intellect to be sufficient unto itself to bring about understanding without the resources of the agent intellect. Therefore, in whatever way it might be said that the passive intellect is susceptible to the activity of the agent intellect, whether as to an agent distinct from images or as from thinking, it is false and foreign to Aristotle. And since each of these sects will have erred, they will also have erred in a third way as  one error entails another, so that it is made clear by the following considerations.


Notes to Chapter 3 of Zabarella’s De Mente Agente

Main topics covered: Aristotle’s theory of vision, intromission and extromission theories of vision, the relationship between perception and the intellect, the signification of the term “habitus”/hexis, hexis in relation to ethics, the relationship between the intellect as a hexis as a “maker” and as a “form,” efficient causality and the intellect, Aquinas and species as moving causes of intellection.

Note 1:  The term “motiva” might well seem to come in oddly here and it might even be wondered whether this is a reference to the extramission theory of vision that was widely accepted during the renaissance, since the analogy clearly pertains to the conditions necessary for sight (for two sources on the history of theories of vision, see below). However, Zabarella discusses the Aristotelian explanation of vision in terms of movement following Aristotle’s text, the main points of which are to be found in De Anima II.7 at 418b1:

Every color has in it the power to set in movement what is actually transparent;

at 419a9-10:

At present it is obvious that what is seen in light is always colour. That is why without the help of light colour remains invisible. Its being color at all means precisely its having in it the power to set in movement what is actually transparent, and the actuality of what is transparent is just light.

and again at 419a13-15:

Color sets in movement what is transparent, e.g. the air, and that, extending continuously from the object of the organ, sets the latter in movement. (1)

These three texts provide us with the basics of Aristotle’s theory of vision, according to which the color of an object acts upon an illuminated medium (i.e. the otherwise unoccupied translucent field of air between the eye and the visible object) to effect a change in the sense organs, which it accomplishes by means of a movement it produces within the medium.  Finding the eye to contain a watery substance, Aristotle thought that the water in the eye was susceptible of carrying the movement produced by the color of an object, so that it, in turn, produced sight within the eye (cf. De Sensu et Sensibilia, 438b where Aristotle makes explicit that the eye is capable of admitting light and that the eye is the proper site of the conjunction of the power of vision with what it seen-something that according to the Platonic extromissionist theory, required the emission of light outside the organ of the eye itself).

In line with the Aristotelian view, when commenting on the first quoted text above, Zabarella writes that the illuminated medium of vision is that “per quod fit actio obiecti in sensum hoc enim erit progredi ab obiecto ad operationem” (in Textus 68, page 119 (pdf pp. 336ff.)). Here the medium might be thought of as a necessary condition for action on the senses to take place and for them to be made active. Later in commenting on the same text, he writes that a property of color is that it is able to set a transparent medium in motion. Interestingly, he goes on to say that the precise way in which it causes this motion is by imprinting its “species,” its (potentially visible) form upon the medium of vision:

Movere autem perpsicuum nil aliud eft, quam imprimere in eo speciem suam, quae est alteratio perspectiva, de qua in praecedentibus dictum eft

Zabarella’s commentary therefore follows closely the Aristotelian version of the intromissionist theory  of vision, according to which the “eidos” (image, idea, form) of an image is transfered to the eye itself.

Attention to the elements in this theory (agent, patient, object) helps to clarify the way in which sight is analogous to thought and is Zabarella’s main preoccupation here.  The analogy is directly applicable to De Anima III.4, where Aristotle, in comparing the mind to the sense organs, says that it must be  capable of receiving the form of an object, so that it is potentially identical to its object without being its object (cf. 429a15-17):

ἀπαθὲς ἄρα δεῖ εἶναι, δεκτικὸν δὲ τοῦ εἴδους καὶ δυνάμει τοιοῦτον ἀλλὰ μὴ τοῦτο, καὶ ὁμοίως ἔχειν, ὥσπερ τὸ αἰσθητικὸν πρὸς τὰ αἰσθητά, οὕτω τὸν νοῦν πρὸς τὰ νοητά. (See the tlg for an online greek text)

I translate:

[The potential intellect] “Must be impassive, but receptive of the form and potentially such [i.e. as the form] while not becoming the former and to be of such a nature that, just as the sense organs are related to what is sensible, so the intellect is related to what is intelligible.”

In the text that follows, Zabarella distinguishes the role the agent intellect plays in the process of making potentially intelligible objects actually intelligible. His primary claim here is that, while it may be considered an agent, its action upon potentially intelligible objects is such that it involves the contribution of a form-light-that makes them actually intelligible.

(1) These are translated by J.A. Smith, in The Complete Works of Aristotle, The Revised Oxford Translation, Edited by Jonathan Barnes, vol.1, Bollingen: 1995, pp. 666-667.

Note 2: Zabarella is here referring to De Anima III.5 430a15, where Aristotle writes that the agent intellect that makes all things is kind of “disposition,” like light:

καὶ ἔστιν  μὲν τοιοῦτος νοῦς τῷ πάντα
γίνεσθαι δὲ τῷ πάντα ποιεῖνὡς ἕξις τιςοἷον τὸ φῶς·

The term habitus translates into Latin the Greek term ἕξις.  One difference between the two is that “ἕξις” is a substantive formed from the future tense of the verb “to have,” (thus “will have”) whereas habitus is a substantive apparently coined by Aristotle’s Latin translators directly from the past participle of the verb “to have, hold” (thus “has had”)  and has “clothing” or “garment” one puts on as a synonyms, whence we get the word “habit.” Thus, in Greek it signifies a “will have” and something one “has obtained” or “holds” or perhaps metaphorically, “puts on” in the Latin. In either case, in ethical contexts, the term ordinarily conveys the idea of an disposition to act in a certain way that is not easily acquired and that is kind of addition to one’s given nature. Aristotle commonly uses the term διάθεσις as a synonym (cf. for example Metaphysics V.20 where Aristotle discusses the definition of ἕξις), which can be analyzed morphologically into the notion of “directedness to an end” (διά) and a “placing,” “setting down,” or “positioning,” thus conveying the idea of an orientation to something.

In the context of Aristotelian ethics, the term fits neatly into the framework of character development as a fulfillment of one’s nature. For this reason, some have taken issue with “habit” as a translation in such contexts, since it does not adequately distinguish between the kind of “habit” (if the term fits at all) that is acquired by accident and one that is established deliberately in the attempt to attain some particular kind of excellence (See, for example, J.J. Glanville’s discussion of the term in The Material Logic of John of St. Thomas, p. 611, note 5, pdf page 641).  In the present context, a habitus refers not to an acquired, but to an innate disposition, however, making “disposition,” or perhaps even “faculty” or “power” better choices.

But the term can also be used more broadly to indicate the polar opposite of a privation (cf. Metaphysics, Book 10.4, 1055a33, whether referring to a natural state or to an acquired one.  In Categories 12a36, Aristotle uses the term to describe the possession as opposed to the privation of sight. There may be a sense in which the semantic richness of the term can be brought out with reference to the contrast between the potential and agent intellect in this respect: one represents the possession of a disposition toward a certain kind of activity, whereas the other represents its polar opposite: a privation of any ability to actualize knowledge on its own.  Furthermore, in the soul as a whole, the agent intellect is a habitus in the sense of being a disposition like sight, but also represents a natural ability that is the basis for further acquired abilities that lead to excellence.  In this sense it is a natural disposition such as the hand naturally has, to make things, being its intellectual counterpart, as Aristotle writes in De Anima III.8, 432a1-2,

ὥστε ἡ ψυχὴ ὥσπερ ἡ χείρ ἐστιν· καὶ γὰρ ἡ χεὶρ ὄργανόν ἐστιν ὀργάνων, καὶ ὁ νοῦς εἶδος εἰδῶν καὶ ἡ αἴσθησις εἶδος αἰσθητῶν.

“So that the soul is like the hand: for even as the hand is the tool of tools, so too the intellect is the form of forms and perception is the form of  perceptions”

(My trans.)

Extending this consideration to the ethical realm, it is a possession of the soul that, in making all things, is of even more fundamental importance than the hand, as that without which wisdom, practical or otherwise, could not be acquired.


*The Greek texts quoted from the de Anima and Metaphysics here are taken from Ross’s critical editions, while the Categories quotes from the 1949 Oxford edition of Aristotle’s works.

L. Minio-Paluello, Aristotelis categoriae et liber de interpretatione, Oxford: Clarendon Press, 1949 (repr. 1966): 3-45 (1a1-15b32).

W.D. Ross, Aristotle. De anima, Oxford: Clarendon Press, 1961 (repr. 1967)

W.D. Ross, Aristotle’s metaphysics, 2 vols., Oxford: Clarendon Press, 1924 (repr. 1970 [of 1953 corr. edn.]): 1:980a21-1028a6; 2:1028a10-1093b29.

Note 3: In his treatise, De Speciebus Intelligibilibus (see pdf p.730), Zabarella attributes the view that species impressa, i.e. the forms of things that have been “impressed” upon the intellect in the same way that visual forms affect the eye, act as an efficient, motive cause of intellectual activity (sp. apprehending the “forms” of things) to Aquinas and Zimara, who he says followed him in his opinion on the issue:

sic igitur species intelligibilis impressa in intellectu est ratio formalis, qua intellectus operatur.; non operatur autem, nisi a phantasmate moueatur, ideo phantasma lo- cum habet obiecti mouentis

sed opinionem Thomae sequi videtur Zimara in theoremate. 82. vbi afferit fpeciem in intellectu impressam esse principium effectivum intellectionis, hoc eft rationem formalem, qua intellectus, qui possiblis dicitur , est intellectionis productivus .

For Aquinas, he references Commentary on the De Anima, Book III, Commentary 8 and the Summa Theologiae, I,85 as textual sources.

Thus, Zabarella distinguishes the causal role of the agent intellect from that of the object of thought, which might be supposed to move one to think. In fact, it acts upon the object in such a way that, according to the analogy, it brings to it the form of light, a “perfection” of the colors themselves, making potentially visible colors into actually visible (i.e. intelligible). Such a light would not thereby alter the nature of such colors, but make them actually visible inasmuch as they are already potentially visible (Aristotle says that it is specifically being colored that makes objects visible, with light as a further necessary cause-see references to note 1 above).


See pdf pg. 730 or pp. 686-7 of Zabarella’s De Speciebus Intelligibilibus  in the collection, De Rebus Naturalibus,  Venice: 1590.

Zabarella’s On the Actualizing Mind, Chapter 2: Various Opinions Concerning the Proper Activities of the Actualizing Intellect

Chapter 2: Various Opinions Concerning the Activities Proper to the Actualizing Intellect

CERTUM est officium mentis agentis esse agere, hoc est trahere de potestate ad actum, sed in quodnam agere dicatur, & quomodo, obscurissima res est, & maxime controversa: alii namque dicunt ipsam agere in phantasmata, non in mentem patibilem; alii in mentem patibilem; alii in mentem patibililem, non in phantasmata; alii vero in ambo simul.



Prima sententia Latinorum fuit, praesertim D. Thomae, qui in 3 Libro de anima, & in prima parte summae quaest. 79, artic. 3 & 4, and in quaestionibus disputatis de spiritalibus creaturis articulo decimo & in locis fusissime de hac re loquitur, asserit rationem agentis in hoc esse constituta, ut agat in phantasmata:



eiusdem sententiae est Ioan. Bacconius in primo sententiarum  q. 2. prologi, ubi dicit officium intellectus agentis esse propter phantasmata, & totam eius actionem in phantasmatibus terminari, neque ulterius progredi.

Pro hac opinione videtur argumentum sumi ex verbis Aristot. in contex. 13, tertii, libri de anima, ubi declarans officium intellectus agentis inquit ipsum esse sicut lumen, nam lumen facit colores, qui potestate sunt, esse actu colores: quemadmodum igitur lumen non agit in oculum, sed in obiectum colorem, & ipsum ducit de potestate ad actum; ita intellectus agens agit in phantasmata, non in intellectum patibiliem;



ideo potest inde colligi argumentum tale: officium omnis agentis est trahere de potestate ad actum; sed Arist. hoc officium tribuit intellectui agenti ratione obiectorum, facit enim de intellectis potestate actu intellecta; ergo in phantasmata agit, non in intellectum patibilem.




Contra vero Simplicius videtur ei total actionem tribuere respectu intellectus patibilis; putat enim utrunque esse unam & eandem substantiam, & unum intellectum, qui ut in se manens dicatur agens, & ut progressus dicatur patibilis; quoniam ipse ut in se manens seipsum ut progressum ducit de potestate ad actum, de imperfectione ad perfectionem. Hanc sententiam Aver. in commentario quinto tertii libri de anima [cf. pdf page 411] Themistio attribuit, attamen non satis liquet Themistiarum fuisse huius opinionis (Note 2).


Hanc eandem sequitur Ioannes Gandavensis in quaestiones 24 & 25 tertii libri de anima, ubi totam actionem intellectus agentis inquit esse in intellectum patibilem, non in phantasmata, & ipsum in intellectu patibili producere actum intelligendi.


Pro hac sententia sumitur argumentum ex Arist. in contex. 17 eiusdem libri, ubi ex eo quod detur intellectus patiens, infert dari etiam intellectum agentem propterea quod omni patienti respondet aliquod agens: vult igitur Arist. intellectum patientem, & ut agat in eum:



ratio nanque illa vana esset, nisi agens ageret in illudmet patiens, cui respondere debet:

hoc idem Arist. exempla declarant; inquit enim intellectum agentem ita se habere ad intellectu patibilem, ut ars ad materiam se habet, ars autem in materiam agit; ita materia prima est patiens, in quod agunt omnia agentia naturalia; quare etiam intellectus patibilis dicitur patiens respectu agentis: nomen quoque ipsum hoc ostendit ; non enim phantasmata vocavit patientia, sed ipsum patibilem intellectum, in hunc itaque voluit agere intellectum agentem.



Averroes autem varius fuisse videtur: quandoque enim asserit actionem intellectus agentis requiri propter intellectum patibilem, ut ipsum ad actum ducat, atque perficiat; quandoque propter phantasmata, ut ea transferat de gradu in gradum, hoc est de materialibus faciat immaterialia, & de intellectis potestate actu intellecta:


quare videtur Averroes existimasse officium intellectus agentis requiri propter utranque actionem ductus


fortasse utrisque argumentis ex verbis Aristotelis sumptis, quibus duas priores sectas usas esse diximus; nam Aristotelis in contextu decimoseptimo tertii libri de anima dicere videtur intellectum agentem agere in intellectum patibilem, deinde in decimooctavo videtur assere ipsum agere etiam in phantasmata.



Ideo sententiam hanc nonnulli recentiores sequuti sunt, qui eam magis declarantes dixerunt intellectum agentem esse idem re cum intellectu patibili, & esse cognoscentem, & eatenus in illum agere, quatenus tribuit illi cognitionem ut hac ratione dicatur intellectionem producere, quia intellecui patibiili tribuit cognitionem, quam ipse agens prius habebat.  Haec sunt, quae ab aliis dicuntur, a me brevissime collecta.

It is certain that the activity proper to the actualizing mind is to act: that is, to draw from a potential state to an actual one. But what it is said to act upon and how is a most obscure matter and generates the greatest controversy.  For some say that is acts upon images, (see note 1) and not upon the mind in a state of potentiality; others, that it does act on the mind in a state of potency; and, to be sure, some say that it acts upon both together.

Thomas Aquinas

The first opinion was proposed by the Latin authors, but most notably by Saint Thomas, who, in his commentary on Book 3 of the de Anima and in the first part of the Summa, Q. 79, articles 3 and 4, and in Disputed Questions on Created Spirits, art. 10 and in very widely scattered places discusses this topic. He asserts that the nature of its agency consists in this: that it acts upon images.

 John Baconthorpe (John Bacon)

John Bacon was of this same opinion. In the first book of his Commentary on the Sentences, Q. 2 he writes that the activity proper to the actualizing intellect is in relation to images, and that the entirety of its action terminates in images and does not proceed further.

In favor of this opinion, it appears that the argument is taken from Aristotle’s words in Contextus 13, of Book 3 [de Anima 3.5], where, when he is speaking of the the activity proper to the actualizing intellect, Aristotle says that it is like a light, for it makes colors, which were in a state of potentiality, to exist as actual colors.  Therefore, just as light does not act upon the eye but on the colored object and takes it from a state of potentiality into actuality, so the actualizing intellect acts upon images and not upon the intellect in a state of potentiality.

It follows that an argument can be gathered therein of the following kind: [1] the activity proper to every actualizing element is to draw from a state of potentiality to actuality; moreover, [2] Aristotle attributes this function to the actualizing intellect on account of its objects, for it makes its objects actually understood from ones that are potentially understood. Therefore,  [3] it acts upon images and not in the passive intellect.


Simplicius, to the contrary, seems to attribute its entire activity to the passive intellect, for he thought that each was one and the same substance and one intellect, which, as abiding in itself  is called an agent, but as a process is called “passive.” As abiding in itself he considered it a “self-same” thing; as a process it moves from a state of potentiality to one of actuality, from an unfinished state to a state of completion. Averroes attributes this opinion to Themistius in his comment 5 on the third book of the de Animaalthough, it is not quite clear that this was the opinion of Themistius (Note 2).

Jean of Jandun (Johannes Gandavensis)

Jean of Jandun follows the same view in questions 24 and 25 in the third book of the Quaestiones de Anima, where he says that the entire action of the actualizing intellect is upon the passive intellect, not upon images, and that it brings about the act of understanding in the passive intellect.

In support of this view, an argument is taken from Aristotle’s works in context 17 of the same book, where, from the fact that a passive intellect is present, Aristotle infers that an actualizing intellect must also be present, accordingly, since to every potentiality there corresponds an actualizing agent, Therefore, it is claimed that Aristotle intends for there to be a passive intellect so that the actualizing intellect might act upon it. That reasoning would be pointless unless the actualizing agent were to act upon that very passive element to which it must correspond. When Aristotle discusses this same point he uses examples: for instance, he says that the actualizing agent is related to the potential intellect as a craft is related to matter and moreover, as craft acts on matter, : in the same way prime matter is a passive principle on which all natural agents act; wherefore, the passive intellect is also called “passive” with respect to an agent; [3] its very name indicates this too: for he did not call images passive, but the passive intellect itselfand so he intends for the agent intellect to act upon the latter.


But Averroes seems to held a different opinion: for sometimes [a] he asserts that the action of the actualizing agent is required for the passive intellect, so that it might bring it to actuality and bring it to completion; and sometimes [b] he says that the activity of the agent intellect it is for the sake of images, so that it may transfer them from one step to the next-that is, so that it makes immaterial objects out of material ones and and bring potential intellgibiles to actual intelligibility. For that reason, Averroes seems to have supposed that the proper activity of the agent intellect is required for each action of taking from potentiality to actuality.

Both arguments may perhaps be taken from Aristotle’s words we said the two prior sects made use of: for Aristotle in contextus 17 of book III [De Anima III.5] of the De Anima seems to say that the actualizing intellect acts acts on the passive intellect, but then, in contextus 18 [cf. note 3], he seems to assert that it also acts upon images. Therefore, several recent authors have followed this opinion, who, expounding it to a greater extent, have said that the agent intellect is the same thing as the passive intellect, that it is a knows, and insofar as it acts upon it, gives it knowledge. By this reasoning it is said to produce intellectual activity, since it gives knowledge to the passive intellect that the agent intellect first posessed. These are the opinions which are given by others, which I have very briefly collected.

Notes to Chapter 2 of the Translation of Zabarella’s De Mente Agente

Main Topics Covered: the intellect and its relationship to images, forms and images, De Anima III.7, outline of primary theses covered in Averroes account of the Intellect with textual references, the influence of Themistius upon Averroes

Note 1: It might be wondered whether a broader term than “images” should be required here.  After all, the mind forms its concepts on the basis of mental content besides images. However, the phrase nequaquam sine phantasmate intelligit anima, (“the soul never understands without an image”) as a translation of Aristotle’s De Anima III.7, 431a15, was often commented on and understood in terms of the mind having the productions of the imagination as its objects of contemplation (For Scotus’ text, Quaestiones de Anima on this topic, click here).  In De Anima III.7, Aristotle distinguishes images from sense perceptions (cf. 431a14) in describing images as the proper objects of the mind. Aristotle may have had a case in mind such as the way a student of geometry might imagine various shapes in forming ideas about them.  An idea of importance to Thomists was that, in doing so, the student might be able to transcend images and attain pure ideas.  A clue that Aristotle may have had something like the latter in mind is when he says at the end of De Anima III.7 that the mind “thinks the forms in images,” and goes on to describe different types of images: natural (a snub nose presumably belonging to Socrates) and mathematical (the curvature of the nose). In commenting on this in his commentary on the De Anima Thomas writes:

Abstrahit tamen circa naturalia intellectus universale a particulari simili modo, inquantum intelligit naturam speciei sine principiis individuantibus, quæ non cadunt in definitione speciei (cf. the full text here)

The term “species” in Aquinas’ commentary refers to the form the intellect receives from the image having universal content.

Note 2: The text of Comment 5 contains the textual source for Averroes’ thesis that the material intellect (1) does not have a material form; (2) is conjoined with the agent intellect; and (3) is one for all humans. He can be seen attributing the first opinion to Themistius on pdf page 413 in the Crawford edition of the Long Commentary. Brief textual sources for all three are presented here for convenience:

Et hoc idem induxit Theofrastum et Themistium et
plures expositores ad opinandum quod intellectus materialis
est substantia neque generabilis neque corruptibilis.
60 Omne enim generabile et corruptibile est hoc; sed iam
demonstratum est quod iste non est hoc, neque corpus neque forma in
corpore. Et induxit eos ad opinandum, cum hoc, quod ista est sententia

The second reads as follows:

Et ideo opinatus est Themistius quod nos sumus intellectus
agens, et quod intellectus speculativus nichil est aliud
nisi continuatio intellectus agentis cum intellectu materiali
tantum. Et non est sicut existimavit, sed opinandum est quod in
anima sunt tres partes intellectus, quarum una est intellectus 570
recipiens, secunda autem est efficiens, tertia autem factum.
Et due istarum trium sunt eterne, scilicet agens et recipiens;
tertia autem est generabilis et corruptibilis uno
modo, eterna alio modo (cf. pdf pg. 430)

Finally, the third opinion (not attributed directly to Themistius) is here:

Quoniam, quia opinati sumus ex hoc sermone quod 575
intellectus materialis est unicus omnibus hominibus, et etiam                                          ex hoc sumus opinati quod species humana est eterna, ut
declaratum est in aliis locis, necesse est ut intellectus
materialis non sit denudatus a principiis naturalibus communibus
580 toti speciei humane, scilicet primis propositionibus
et formationibus singularibus communibus omnibus; hec enim
intellecta sunt unica secundum recipiens, et multa secundum
intentionem receptam. (cf. pdf pp. 430-431)

For further discussion on the relationship between Themistius and Averroes on the intellect, see “Themistius and the Development of Averroes Noetics,” by Richard C. Taylor.

Note 3: See pp. 461ff. in Crawford.

Aristotelian “Weakness of Will”


It is sometimes said that Aristotle’s answer to weakness of will is building good habits. Socrates said that to know the good is to do the good. Aristotle objected that people might fail to do the good simply out of weakness of will (laziness, cowardice, etc.). Building good habits, says Aristotle is the key to overcoming weakness of will.  But I wonder if building good habits really is a prescription that works.
Imagine a couch potato who doesn’t have a very strong will. Suppose the couch potato knows that he ought to get off the couch and that its in his best interest to do so. Presumably, Aristotle would advise such a person to start building good habits in order to overcome the problem. He might start by getting up early, turning off the television, creating a schedule and working with a day planner, etc. He might even get off the couch and exercise in his living room. Over time, these habits would become more and more a part of his routine and over time he would become more productive.
But there is what Quine would call “an air of circularity” about this: doesn’t he need more strength of will to start a day planner and exercise and get up early in the first place? If the problem was weakness of will to begin with, won’t that become an obstacle to developing good habits? In short, Aristotle seems to be assuming the the solution to the problem lies in the premises that were introduced to solve it.
How then do you deal with weakness of will itself? Is there any one prescription that actually would work as the core to any w.o.w. problem? We could try pressing further with Aristotle’s solution: perhaps one could engage in will-building exercises. Perhaps one could chart one’s progress in incremental steps. Something tells me this wouldn’t get very far with an entrenched couch potato. But is Aristotle nevertheless right?

On Aristotle’s to ti ên einai and its translation

Aristotle’s phrase, to ti ên einai, is generally understood as a formula for expressing the notion of “essence”.  A problem that has arisen for translators, interpreters, and readers is how to understand the original greek words in a way that makes sense to us today.  The difficulty arises simply from what many have thought to be the disjointedness of the literal translation, which runs, “the what it was to be,” or as some have rendered it, “the what it was being”.

Photo by the author, Gem Lapin Beaucoup

One prominent suggestion for how to deal with the phrase comes from the Aristotelian scholar, Joseph Owens. Owens argued that the “was” in the phrase should be understood not literally, but in terms of its imperfective aspect.  Thus ên (“was” above) would be read as connoting an action taking place in a “timeless present” (“was” in its imperfetive sense carries the idea of an action without a start or an end).  Thus, the translation Owens recommends emerges as “the what-IS-being” (here the ‘was’ becomes a timeless ‘is’).  Moreover, as might be expected in the context of his book “The doctrine of being in the Aristotelian metaphysics”, Owens builds metaphysical implications into the timelessness of the IS in the expression, saying that it points us to what “essentially, necessarily is” in a thing, apart from the “unintelligible matter…which is the principle of contingency and change” in a thing.  Many translators choose to simply gloss the phrase as “essence”; but Owens’ translation serves as an attempt to work through the language to uncover the thinking behind the literal meaning of the phrase.

Owens’ treatment is indeed useful in developing Aristotelian concepts that are latent in the language. Nevertheless, I believe that an older tradition which translates the phrase more in terms of its literal meaning, which leaves the “was” intact also reveals a great deal about the notion of essence that should not be cast aside.  In what follows, I would  like to point out that there are ways in which his view complements the one being the literal rendering offered here, but also that there are important ways in which it may lead a reader to conclusions that are unlikely to have been accurate.


Photo by the author, Gem Lapin Beaucoup

To take up the complementarity between the “was” and “IS” translations first, it is important to see that Owens’ “the what-IS-being” emphasizes an aspect of form that places it outside of time in a way that contrasts with “the contingency of matter and change, upon which time follows” (4).  In this precise sense of form, it coincides with an understanding of form not as present in things, but as ideally separate in a way that coincides with a more Platonic sense of “form.”  Needless to say, this is, as was hinted at in the opening a highly metaphysical sense of form.  There is, of course, a sense in which one can consider “form” as abstracted in thought from all matter in which case it becomes literally an idea or else a celestial object in Aristotle’s cosmos.  Such a conception would lead one to consider form as manifested in matter apart from matter, and in this sense it coincides with one of the principles of the natural world, as one of the senses of ousia (the one that coincides with entelecheia) outlined above.

What is lacking in this reading is that it seems to forget that the entelechy in view is equally an aspect of ousia as it is experienced in the world around us.  Several of Aristotle’s pronouncements on the proper methodological approach to the natural sciences point in this direction, and it is perhaps as clear in De Anima II.2 as anywhere.  At the beginning of II.2, at 413a9-16, Aristotle is concerned to go beyond the the facts gathered together in the initial, general treatment of the soul in De Anima II.1 to access the core, so to speak, of what makes it what it is.  In doing so, he will proceed from what is more evident to the senses (phaneroteron) to an explanation that is more intelligible and clear as a reasoned account (kata ton logon). (5)  What should be noticed is that in doing so, Aristotle is in search of a cause that will explain the presence of the phenomenal facts gathered in the first section.  That cause or reason will have two aspects: one mentioned immediately above that is purely intelligible and can be grasped in terms of its logos or account, and another that is present in the thing: an aspect emphasized in the present context where he says that the cause sought after must be phenomenally present in the subject under discussion (alla kai ten aitian enhuparchein kai emphainesthai).  These are the two familiar poles of Aristotle’s notion of understanding, his fundamental starting points of knowledge (logos and sense experience) which must be connected if any truly explanatory demonstration is to be possible.

Any account of “essence” for Aristotle must be consistent with these two aspects of the cause or reason that explains what a thing is.  Moreover, as one might have glimpsed, these two aspects can and should be related to the three-fold division of ousia Aristotle draws out explained above as entelecheia (actuality), dunamis (potentiality), and the composite of the two.  In searching for the cause of the observable phenomena associated with a thing, one is likewise in search of its underlying actuality, or, again, that which makes a thing what it is.  Owens’ account would have our understanding of essence limited to actuality apart from all potentiality or coming to be not only in terms of its logical, rational formula (cf. kata ton logon above)  but also in terms of its existence in a composite thing.  That this is in fact what Owens is up to can be seen most clearly where he writes that “The notion back of the imperfect therefore should be that of necessary Being….” and again where he says his treatment of to ti ên einai “implies that the form is the fundamental Being of the thing”. However, most decisively, Owens writes that due to timelessness of this “Being”, “the Greek imperfect cannot be taken here as denoting past time” since “It refers in this phrase to something still present, and applies equally well to the timeless separate Forms.” (6)

Now, interestingly, Owens arrives at a sense of the role of to ti ên einai in Aristotle’s researches into the natural world that is perfectly compatible with the three-fold analysis of ousia given above.  This can be seen where Owens presents matter, form, and the composite as possible answers to the socratic “what-is-it”  question and then relates to ti ên einai exclusively to the formal aspect of what a thing is (pp. 186-7).  Owens relates this type of “Being” not merely to the form of a thing but also attempts depict it to the formal cause of a thing in a way consistent with his earlier characterization saying that, “The form appears to be ’cause’ in the highest sense, and as such is the ‘Entity’ of the what-IS-Being of the thing to which it is the cause”.  (7)  It does not seem to occur to Owens that there is a discrepancy between (a) his fully separate “Being” and (b) the role to ti ên einai plays in relation to ousia as analyzed in terms of the natural world: such an ousia is not, as the example of his treatment of the soul makes clear, to be understood as an abstraction from things, but the being of things.  The formal causality that such a being brings to composite being is more in tune with being in time rather than “Being” construed as separate and timeless.  This is brought out explicitly where Aristotle, at 412a27 writes that the soul is the first entelechy (lit. being-at-its-goal) of a physical body potentially having life, supporting among other things, waking and sleep.  Such beings can come into and go out of being in the natural world; only as mental abstractions or when considered as necessary within a logically based ontological reconstruction of the cosmos do they have a necessary being.  Thus, it seems it must be concluded that however strange Aristotle’s formulation may initially seem, it would be misleading to characterize to ti ên einai as indicating a purely timeless, abstract Being in all contexts.


Photo by the author, Gem Lapin Beaucoup

The question presents itself, then, whether Owens’ understanding of to ti ên einai in the Metaphysics ought to be taken as peculiar to that context or whether it might be construed as a more architectonic way of treating the phrase than the more temporal interpretation of essence given by the traditional translation.  It follows from what has been argued above that, precisely as it has been formulated, Owens’ translation will not stand as a more architectonic way of understanding of the role of to ti ên einai.  This should be evident from the fact that it is not applicable without qualification to the context of natural science (the method announced in the De Anima being applicable to the natural sciences generally).  On the other hand, as alluded to above, there is a sense in which the metaphysical reading of to ti ên einai is compatible with a more everyday physical way of considering being.  What, then, is the proper way of conceiving the relation between entelectic being and Owens’ Being?

If there is a priority that may be given to the metaphysical sense, it will not be one that connotes a platonic sense of essential Being.  That sense does not apply generally, if at all to Aristotle’s researches in natural science.  It may apply to the immaterial heavenly bodies of an Aristotelian cosmos; but even in such a context, may we be said to be contemplating a kind of Being that is truly timeless?  Such beings would seem to require a separate realm if  taken to be entities in Aristotle’s sense.  Recall that the planets do have motion-in their revolutions. (8)  I propose that the proper sense that belongs to the metaphysical formulation should be construed as compatible with what is for Aristotle kata ton logon (cf section 2 above), which amounts to a way of seeing or considering reality mentally that is purely intelligible and that allows for contemplation.  This mode of apprehending the world contrasts with a phenomenologically based one that forms the ultimate starting point of investigation.

Thus, I believe the type of priority Owens’ formulation will bear is one that is compatible with the order of explanation or of demonstration when full understanding has been attained: that is, when experience is explained with consistency by a governing principle, reason, or cause; or, again, when the logical account we give of things has attained both internal coherence and external coherence with the phenomena it explains.  This is obviously a sense in which the form of a thing, considered as an arche of understanding may have a logical priority over the observable phenomena associated with it it is meant to explain.  But this priority is of an entirely different order than a more ontological one that considers ousia as a component of things in the natural world.  Nevertheless, despite the apparent incompatibility, there is a place within Aristotle’s metaphysics where the two orders merge: where ousia is identified in Metaphysics Book Z as the foundation of everyday being, and more especially, associated with the formal reality that is in things.

This is in fact, what I believe should provide the locus for a more architectonic understanding of to ti ên einai.  It is in the context of Z that to ti ên einai is identified with the formal nature that is in things as a metaphysical principle.  This is a metaphysical sense that is compatible with being in time as considered in the physical world.  It may be applied to Aristotle’s analogy involving an axe: things come to have particular being, to be individual substances of a certain type when they can also be said to have a certain entelechy that is compatible with the way such things are ordinarily described.  In the case of an axe, this ordinary description will involve its having a blade, and in a very everyday sense, just as a lump of iron will not be an axe until it has a blade, so a particular sort of body will not be living unless it has a soul, and so on for other cases in the natural world.  When things become what is compatible with the way we ordinarily describe them they are what we say they are; an account of their essence clarifies just what it is that unifies such descriptions and explains the natural phenomena before us.  Such an account is precisely what Aristotle intends by the phrase to ti ên einai which indicates what sort of attribute or attributes a thing must possess if it is to be a certain kind of thing.  This being stands as the fulfillment of what a thing was-to-be.


(1) See The Doctrine of Being in the Aristotelian Metaphysics, p. 181.

(2) See Philoponus’ Commentary on the De Anima, under the pages marked with the Bekker number corresponding to the text.

(3) Cf. the text of Aristotle’s de Anima, II.1, ll. 412a6ff.

(4) Owens esp. pp. 183-184.

(5) 413a12 of DA II.2.

(6) Owens, pp.184-185

(7) Owens, p. 188.

See Aristotle’s Metaphysics, V.13, 1020a29-33, where Aristotle relates time to space and movement


Owens, Joseph.  The Doctrine of Being in the Aristotelian Metaphysics (3rd ed.).  (Toronto: Pontifical Institute of Mediaeval Studies, 1978). 

Ioannis Philoponi in Aristotelis De anima libros commentaria / consilio et auctoritate Academiae Litterarum Regiae Borussicae ; edidit Michael Hayduck.  (Berolini: Typis et Impensis G. Reimeri, 1897).

Aristotle. de Anima (ed. W.D. Ross).  (Oxford: Clarendon Press, 1961).