Considerandum autem quod formae in rebus corporeis particulares sunt et materiale esse habentes, in intellectu vero universales sunt et immateriales: quod quidem demonstrat intelligendi modus. Intelligimus enim res universaliter et immaterialiter; modus autem intelligendi speciebus intelligibilibus quibus intelligimus, necesse est ut correspondeat: oportet igitur quod, cum de extremo ad extremum non perveniatur nisi per medium, quod formae a rebus corporeis ad intellectum perveniant per aliqua media. However, we must realize that forms in bodily things are particular, and have a material existence. But in the intellect they are universal and immaterial. Our manner of understanding brings this out. That is, we apprehend things universally and immaterially. This way of understanding must conform to the intelligible species whereby we understand. Consequently, since it is impossible to pass from one extreme to another without traversing what lies between, forms reaching the intellect from bodily objects must pass through certain media. Huiusmodi autem sunt potentiae sensitivae, quae formas rerum materialium recipiunt quidem sine materia, fit enim in oculo species lapidis sed non materia; recipiuntur tamen in potentiis sensitivis formae rerum particulariter, nam potentiis sensitivis non nisi particularia cognoscimus. Necesse igitur fuit hominem ad hoc quod intelligat etiam sensus habere. Huius autem signum est quod cui deficit unus sensus, deficit scientia sensibilium quae illo sensu apprehenduntur, sicut caecus natus de coloribus scientiam habere non potest. These are the sense faculties, which receive the forms of material things without their matter; what lodges in the eye is the species of the stone, but not its matter. However, the forms of things received into the sense faculties are particular; for we know only particular objects with our sense faculties. Hence man must be endowed with senses as a prerequisite to understanding. A proof of this is the fact that if a man is lacking in one of the senses, he has no knowledge of sensible objects that are apprehended by that sense. Thus a person born blind can have no knowledge of colors. Capitulum 83 Chapter 83 Quod necesse est ponere intellectum agentem That it is necessary to posit an agent intellect Inde autem manifestum fit quod scientia rerum in intellectu nostro non causatur per participationem aut influxum aliquarum formarum actu intelligibilium per se subsistentium, sicut Platonici posuerunt et alii quidam ipsos sequentes, sed intellectus acquirit eam a rebus sensibilibus mediantibus sensibus. This discussion brings out the truth that knowledge of things in our intellect is not caused by any participation or influence of forms that are intelligible in act and that subsist by themselves, as was taught by the Platonists and certain other philosophers who followed them in this doctrine. Rather, the intellect acquires such knowledge from sensible objects through the intermediacy of the senses. Sed cum in potentiis sensitivis formae rerum sint particulares, ut dictum est, non sunt intelligibiles actu sed potentia tantum: intellectus enim non nisi universalia intelligit. Quod autem est in potentia non reducitur in actum nisi ab aliquo agente; oportet igitur quod sit aliquod agens quod species in potentiis sensitivis existentes faciat intelligibiles actu. Hoc autem non potest facere intellectus possibilis, ipse enim magis est in potentia ad intelligibilia quam intelligibilium activus; necesse est igitur ponere alium intellectum qui species intelligibiles in potentia faciat intelligibiles actu, sicut lumen facit colores visibiles potentia esse visibiles actu: et hunc dicimus intellectum agentem, quem ponere non esset necesse si formae rerum essent intelligibiles actu, sicut Platonici posuerunt. However, since the forms of objects in the sense faculties are particular, as we just said, they are intelligible not in act, but only in potency. For the intellect understands nothing but universals. But what is in potency is not reduced to act except by some agent. Hence there must be some agent that causes the species existing in the sense faculties to be intelligible in act. The possible intellect cannot perform this service, for it is in potency with respect to intelligible objects rather than active in rendering them intelligible. Therefore, we must posit some other intellect, which will cause species that are intelligible in potency to become intelligible in act, just as light causes colors that are potentially visible to be actually visible. This faculty we call the agent intellect, which we would not have to postulate if the forms of things were intelligible in act, as the Platonists held. Sic igitur ad intelligendum primo necessarius est nobis intellectus possibilis, qui est receptivus specierum intelligibilium; secundo intellectus agens qui facit intelligibilia actu. Cum autem intellectus possibilis iam fuerit per species intelligibiles perfectus, vocatur intellectus in habitu, cum species intelligibiles sic iam habet quod possit eis uti cum voluerit, medio quodam modo inter potentiam puram et actum completum; cum vero praedictas species in actu completo habuerit, vocatur intellectus in actu: sic enim actu intelligit res, cum species rei facta fuerit forma possibilis intellectus; propter quod dicitur quod intellectus in actu est intellectum in actu. To understand, therefore, we have need, first, of the possible intellect which receives intelligible species, and second, of the agent intellect which renders things intelligible in act. Once the possible intellect has been perfected by the intelligible species, it is called the habitual intellect, for then it possesses intelligible species in such a way that it can use them at will; in other words, it possesses them in a fashion that is midway between pure potency and complete act. But when it has these species in full actuality, it is called the intellect in act. That is, the intellect actually understands a thing when the species of the thing is made the form of the possible intellect. This is why we say that the intellect in act is the object actually understood. Capitulum 84 Chapter 84 Quod anima humana est incorruptibilis That the human soul is incorruptible Necesse est autem secundum praemissa, intellectum quo homo intelligit incorruptibilem esse. Unumquodque enim sic operatur secundum quod habet esse; intellectus autem habet operationem in qua non communicat sibi corpus, ut ostensum est, ex quo patet quod est operans per se ipsum: ergo est substantia subsistens in suo esse. Ostensum est autem supra quod substantiae intellectuales sunt incorruptibiles; ergo intellectus quo homo intelligit est incorruptibilis. A necessary consequence of the foregoing doctrine is that the intellect whereby man understands is incorruptible. Every being acts in a way that is conformable to its existence. The intellect has an activity which it does not share with the body, as we have proved. This shows that it can act by itself. Hence it is a substance subsisting in its own being. But, as was pointed out above, intellectual substances are incorruptible. Accordingly, the intellect whereby man understands is incorruptible. Adhuc, proprium subiectum generationis et corruptionis est materia. Intantum igitur unumquodque a corruptione recedit inquantum recedit a materia: ea enim quae sunt composita ex materia et forma sunt per se corruptibilia; formae autem materiales sunt corruptibiles per accidens et non per se; formae autem immateriales, quae materiae proportionem excedunt, sunt incorruptibiles omnino. Intellectus autem omnino secundum suam naturam supra materiam elevatur: quod eius operatio ostendit, non enim intelligimus aliqua nisi per hoc quod ipsa a materia separamus. Est igitur intellectus secundum suam naturam incorruptibilis. Again, the proper subject of generation and corruption is matter. Hence a thing is immune to corruption to the extent that it is free from matter. Things composed of matter and form are essentially corruptible; material forms are corruptible accidentally, though not essentially. Immaterial forms, which are above material conditions, are wholly incorruptible. The intellect by its very nature is elevated completely beyond matter, as its activity shows: we do not understand anything unless we separate it from matter. Consequently, the intellect is by nature incorruptible. Item, corruptio absque contrarietate esse non potest, nihil enim corrumpitur nisi a suo contrario; unde corpora caelestia, in quibus non est contrarietas, sunt incorruptibilia. Sed contrarietas longe est a natura intellectus, in tantum quod ea quae secundum se sunt contraria, in intellectu contraria non sunt: est enim contrariorum ratio intelligibilis una, quia per unum intelligitur aliud. Impossibile est igitur quod intellectus sit corruptibilis. Moreover, corruption cannot take place without contrariety; for nothing is corrupted except by its contrary. This is why the heavenly bodies, which do not admit of contrariety, are incorruptible. But all contrariety is far removed from the nature of the intellect, so much so that things which are contraries in themselves are not contraries in the intellect. The intelligible aspect of contraries is one, inasmuch as one thing is understood in terms of another. Thus it is impossible for the intellect to be corruptible. Capitulum 85 Chapter 85 Quod non est unus intellectus possibilis in omnibus That there is not one possible intellect in all men Forte autem aliquis dicet quod intellectus quidem incorruptibilis est, sed est unus in omnibus hominibus, et sic quod post corruptionem omnium hominum remanet non est nisi unum. Quod autem sit unus tantum intellectus in omnibus, multipliciter astrui potest. An objector may say: the intellect is indeed incorruptible, but there is only one intellect in all men; and so what remains after the corruption of all men is but one. That there is only one intellect for all men, the objector may continue, can be established on many grounds. Primo quidem ex parte intelligibilia quia, si est alius intellectus in me et alius in te, oportebit quod sit alia species intelligibilia in me et alia, in te, et per consequens aliud intellectum quod ego intelligo et aliud quod tu. Erit ergo intentio intellecta multiplicata secundum numerum individuorum, et ita non erit universalis sed individualis. Ex quo videtur sequi quod non sit intellecta in actu, sed in potentia tantum, nam intentiones individuales sunt intellecta in potentia, non in actu. First, on the part of the intelligible species. If I have one intellect and you have another, there will have to be one intelligible species in me and another in you, and consequently there will be one object that I understand and another that you understand. Hence the intelligible species will be multiplied according to the number of individuals, and so it will not be universal but individual. The conclusion would then seem to follow that it is understood not in act, but only in potency; for individual species are intelligible in potency, not in act. Deinde quia, cum ostensum sit quod intellectus est substantia subsistens in suo esse, substantiae autem intellectuales plures numero non sint in una specie, ut supra etiam ostensum est, sequitur si alius est intellectus in me et alius in te secundum numerum, quod sit etiam alius specie; et sic ego et tu non sumus eiusdem speciei. Moreover, since the intellect, as we have seen, is a substance subsisting in its own being, and since intellectual substances that are numerically many do not belong to one species, as we have also seen, it follows that if I have one intellect and you have another that is numerically different, the two must differ specifically. And so you and I would not belong to the same species. Item, cum in natura speciei omnia individua communicent, oportet poni aliquid praeter naturam speciei secundum quod ab invicem individua distinguantur. Si igitur in omnibus hominibus est unus intellectus secundum speciem, plures autem secundum numerum, oportet ponere aliquid quod faciat numero differre unum intellectum ab alio; hoc autem non potest esse aliquid quod sit de substantia intellectus, cum intellectus non sit compositus ex materia et forma. Ex quo sequitur quod omnis differentia quae accipi posset secundum id quod est de substantia intellectus, sit differentia formalis et diversificans speciem. Relinquitur ergo quod intellectus unius hominis non possit esse alius numero ab intellectu alterius, nisi propter diversitatem corporum; corruptis igitur corporibus diversis, videtur quod non remaneant plures intellectus sed unus tantum. Furthermore, since all individuals share in one specific nature, there must be something besides specific nature whereby individuals may be distinguished from one another. Accordingly, if there is one specific intellect in all men, but many intellects that are numerically distinct, something must be found that will make one intellect differ numerically from another. This cannot be anything pertaining to the substance of the intellect, since the intellect is not composed of matter and form. Consequently, any difference that might be admitted on the part of the substance of the intellect would be a formal difference that would cause diversity in the species. The only possibility left is that the intellect of one man cannot differ numerically from the intellect of another man except by reason of the diversity of their bodies. Therefore, when the various bodies are destroyed, it seems that only one intellect, and not a plurality of intellects, would remain. Hoc autem quod impossibile sit, evidenter apparet. Ad quod ostendendum, procedendum est sicut proceditur contra negantes principia, ut ponamus aliquid quod omnino negari non potest. Ponamus igitur quod hic homo, puta Socrates vel Plato, intelligit: quod negare non posset respondens nisi intelligeret esse negandum; negando igitur ponit, nam affirmare et negare intelligentis est. Si autem hic homo intelligit, oportet quod id quo formaliter intelligit sit forma eius, quia nihil agit nisi secundum quod est actu, illud ergo quo agit agens est actus eius, sicut calor quo calidum calefacit est forma eius; intellectus igitur quo homo intelligit est forma huius hominis, et eadem ratione illius. Impossibile est autem quod forma eadem numero sit diversorum secundum numerum, quia diversorum secundum numerum non est idem esse; unumquodque autem habet esse per suam formam: impossibile est igitur quod intellectus quo homo intelligit sit unus in omnibus. The absurdity of this whole position is easily perceived. To make this clear, let us proceed as one would proceed against those who deny fundamental principles. That is, let us establish a truth that simply cannot be denied. Let us suppose that this man, for example, Socrates or Plato, understands. Our adversary could not deny that the man understands, unless he knew that it ought to be denied. By denying he affirms, for affirmation and denial are intelligent actions. If, then, the man in question understands, that whereby he formally understands must be his form, since nothing acts unless it is in act. Hence that whereby an agent acts is his act; just as the heat by which a heated body causes warmth is its act. Therefore, the intellect whereby a man understands is the form of this man, and the same is true of another man. But the same numerical form cannot belong to numerically different individuals, for numerically different individuals do not possess the same existence; and yet everything has existence by reason of its form. Accordingly, the intellect whereby a man understands cannot be but one in all men. Huius autem rationis difficultatem aliqui cognoscentes, conati sunt invenire viam evadendi. Dicunt enim quod intellectus possibilis, de quo supra est habitum, recipit species intelligibiles quibus fit in actu. Species autem intelligibiles sunt quodammodo in phantasmatibus. Inquantum igitur species intelligibilis est in intellectu possibili et in phantasmatibus quae sunt in nobis, intantum intellectus possibilis continuatur et unitur nobiscum, ut sic per ipsum intelligere possumus. Perceiving the force of this difficulty, some endeavor to find a way of escaping it. They say that the possible intellect, of which there was question above, receives the intelligible species by which it is reduced to act. These intelligible species are, in some way, in the phantasms. Hence the possible intellect is continuous and is joined to us so far as the intelligible species is both in the possible intellect and in the phantasms that are in us. It is thus that we are able to understand through the agency of the possible intellect. Sed haec responsio omnino nulla est. Primo quidem quia species intelligibilis secundum quod est in phantasmatibus est intellecta in potentia tantum, secundum autem quod est in intellectu possibili est intellecta in actu; secundum igitur quod est in intellectu possibili non est in phantasmatibus, sed magis a phantasmatibus abstracta. Nulla ergo remanet unio intellectus possibilis ad nos. Deinde, dato quod sit aliqua unio, non tamen sufficeret ad hoc quod faceret nos intelligentes. Per hoc enim quod species alicuius est in intellectu, non sequitur quod ipsum intelligat sed quod intelligatur: non enim lapis intelligit, et si eius species sit in intellectu. Neque igitur per hoc quod species phantasmatum quae sunt in nobis sunt in intellectu possibili, sequitur quod nos sumus intelligentes, sed magis quod nos sumus intellecti, vel potius phantasmata quae sunt in nobis. But this response is completely worthless. In the first place, the intelligible species, as it exists in the phantasms, is a concept only in potency; and as it exists in the possible intellect, it is a concept in act. As existing in the possible intellect, it is not in the phantasms, but rather is abstracted from the phantasms. Hence no union of the possible intellect with us remains. Second, even granting that there may be some sort of union, this would not suffice to enable us to understand. The presence of the species of some object in the intellect does not mean that the object understands itself, but only that it is understood; a stone does not understand, even though a species of it may be in the possible intellect. Hence, from the fact that species of phantasms present in us are in the possible intellect, it does not follow that we therefore understand. It only follows that we ourselves, or rather the phantasms in us, are understood. Hoc autem evidentius apparet si quis consideret comparationem quam facit Aristoteles in III de Anima, dicens quod intellectus se habet ad phantasmata sicut visus ad colores. Manifestum est autem quod per hoc quod species colorum qui sunt in pariete fiunt in visu, non habet paries quod videat, sed quod videatur; neque igitur ex hoc quod species phantasmatum quae sunt in nobis fiunt in intellectu, sequitur quod nos simus intelligentes, sed solum quod simus intellecti. This will appear more clearly if we examine the comparison proposed by Aristotle in Book III of de Anima, where he says that the intellect is to phantasm what sight is to color. Manifestly, the fact that the species of colors on a wall are in our vision does not cause the wall to see, but to be seen. Likewise, the fact that the species of the phantasms in us come to be in the intellect does not cause us to understand, but to be understood. Amplius, si nos per intellectum formaliter intelligimus, oportet quod ipsum intelligere intellectus sit intelligere hominis, sicut eadem est calefactio ignis et caloris. Si igitur idem est numero intellectus in me et in te, sequetur de necessitate quod respectu eiusdem intelligibilis sit idem numero intelligere meum et tuum, dum scilicet simul aliquid idem intelligimus; quod est impossibile: non enim diversorum operantium potest esse una et eadem operatio numero. Impossibile est igitur quod sit unus intellectus in omnibus. Sequitur igitur quod, si intellectus est incorruptibilis ut ostensum est, quod destructis corporibus remaneant plures intellectus secundum numerum hominum. Further, if we understand formally through the intellect, the intellectual action of the intellect must be the intellectual action of the man, just as the heating action of fire and of heat are the same. Therefore, if intellect is numerically the same in me and in you, it follows that, with respect to the same intelligible object, my action of understanding must be the same as yours, provided, of course, both of us understand the same thing at the same time. But this is impossible, for different agents cannot perform one and the same numerical operation. Therefore, it is impossible for all men to have but a single intellect. Consequently, if the intellect is incorruptible, as has been demonstrated, many intellects, corresponding to the number of men, will survive the destruction of their bodies. Ea vero quae in contrarium obiiciuntur facile est solvere. The arguments advanced to support the contrary view are easily answered. Prima enim ratio multipliciter deficit primo quidem quia concedimus idem esse intellectum ab omnibus hominibus, dico autem intellectum id quod est intellectus obiectum; obiectum autem intellectus non est species intelligibilis, sed quidditas rei: non enim scientiae intellectuales omnes sunt de speciebus intelligibilibus, sed sunt de naturis rerum, sicut etiam obiectum visus est color, non species coloris quae est in oculo. Quamvis igitur sint plures intellectus diversorum hominum, non tamen est nisi unum intellectum apud omnes, sicut unum coloratum est quod a diversis inspicientibus videtur. Secundo, quia non est necessarium, si aliquid est individuum, quod sit intellectum in potentia et non in actu, sed hoc est verum in illis tantum quae individuantur per materiam: oportet enim illud quod est intellectum in actu esse immateriale; unde substantiae immateriales, licet sint quaedam individua per se existentia, sunt tamen intellecta in actu. Unde et species intelligibiles quia sunt immateriales, licet sint aliae numero in me et in te, non propter hoc perdunt quin sint intelligibiles actu; sed intellectus intelligens per eas suum obiectum reflectitur supra se ipsum, intelligendo ipsum suum intelligere et speciem qua intelligit. The first argument has many defects. First of all, we concede that the same thing may be understood by all. By the thing understood I mean that which is the object of the intellect. However, the object of the intellect is not the intelligible species, but the essence of the thing. The intellectual sciences are all concerned with the natures of things, not with intelligible species; just as the object of sight is color, not the species of color in the eye. Hence, although there may be many intellects belonging to different men, the thing understood by all may be but one; just as a colored object which many look at is but one. Second, the consequence does not necessarily follow that, if a thing is individual, it is understood in potency and not in act. This is true only of things that are individuated by matter. Of course, what is understood in act must be immaterial. Accordingly, immaterial substances, even though they may be individuals existing by themselves, are understood in act. The same holds for intelligible species, which are immaterial; although they differ numerically in me and in you, they do not on that account lose their property of being intelligible in act. The intellect that understands its objects by means of them reflects upon itself, thereby understanding its very action of understanding as well as the species whereby it understands. Deinde considerandum est quod, etiam si ponatur unus intellectus omnium hominum, adhuc eadem remanet difficultas, quia adhuc remanet multitudo intellectuum, cum sint plures substantiae separatae intelligentes; et ita sequeretur secundum eorum rationem quod intellecta essent diversa secundum numerum, et per consequens individualia et non intellecta in actu. Patet igitur quod praemissa ratio, si aliquid necessitatis haberet, auferret pluralitatem intellectuum simpliciter et non solum in hominibus; unde cum haec conclusio sit falsa, manifestum est quod ratio non ex necessitate concludit. Moreover, we should realize that, even if we admit but one intellect for all men, the difficulty is still the same. There would still remain many intellects, because there are many separate substances endowed with intelligence. And so it would follow, pursuing our adversaries’ line of reasoning, that the objects understood would be numerically different—hence individual and not understood in first act. Obviously, therefore, if the objection under discussion were necessary at all, it would do away with a plurality of intellects simply as such, and not merely in men. Since this conclusion is false, it is obvious that the argument does not follow from necessity. Secunda etiam ratio facile solvitur, si quis consideret differentiam intellectualis animae ad substantias separatas. Anima enim intellectiva ex natura suae speciei hoc habet ut uniatur alicui corpori ut forma, unde et in definitione animae cadit corpus; et propter hoc secundum habitudinem ad diversa corpora diversificatur secundum numerum, quod non est in substantiis separatis. The second argument is readily answered, if we but consider the difference between an intellectual soul and separate substances. In virtue of its specific nature, the intellectual soul is meant to be united to some body as the latter’s form; the body even enters into the definition of the soul. For this reason, souls are numerically differentiated according to the relation they have to different bodies; which is not the case with separate substances. Ex quo etiam patet qualiter tertia ratio sit solvenda. Non enim anima intellectiva ex natura suae speciei habet corpus partem sui, sed unibilitatem ad ipsum; unde per hoc quod est unibilis diversis corporibus diversificatur secundum numerum, quod etiam manet in animabus corporibus destructis: sunt enim unibiles corporibus diversis, licet non actu unitae. This also indicates how the third argument is to be answered. In virtue of its specific nature, the intellectual soul does not possess the body as a part of itself, but has only an aptitude for union with the body. Therefore, it is numerically differentiated by its capacity for union with different bodies. And this remains the case with souls even after their bodies have been destroyed: they retain a capacity for union with different bodies even when they are not actually united to their respective bodies. Capitulum 86 Chapter 86 Quod intellectus agens non est unus in omnibus That the agent intellect is not one in all men Fuerunt autem quidam qui, licet concederent intellectum possibilem diversificari in hominibus, posuerunt tamen intellectum agentem unum respectu omnium esse. Quae quidem opinio, licet sit tolerabilior quam praemissa, similibus tamen rationibus confutari potest. There were also some philosophers who argued that, even granting the diversification of the possible intellect in men, at any rate the agent intellect was but one for all. This view, while less objectionable than the theory discussed in the preceding chapter, can be refuted by similar considerations. Est enim actio intellectus possibilis recipere intellecta et intelligere ea, actio autem intellectus agentis facere intellecta in actu abstrahendo ipsa; utrumque autem horum huic homini convenit, nam hic homo, ut Socrates vel Plato, et recipit intellecta et abstrahit et intelligit abstracta. Oportet igitur quod tam intellectus possibilis quam intellectus agens uniatur huic homini ut forma, et sic oportet quod uterque multiplicetur numero secundum numerum hominum. The action of the possible intellect consists in receiving the objects understood and in understanding them. And the action of the agent intellect consists in causing things to be actually understood by abstracting species. But both these functions pertain to one particular man. This man, such as Socrates or Plato, receives the objects understood, abstracts the species, and understands what is abstracted. Hence the possible intellect as well as the agent intellect must be united to this man as a form. And so both must be numerically multiplied in accord with the number of men concerned. Item, agens et patiens oportet esse ad invicem proportionata sicut et materia et forma, nam materia fit in actu ab agente; et inde est quod cuilibet potentiae passivae respondet potentia activa sui generis, actus enim et potentia unius generis sunt. Intellectus autem agens comparatur ad possibilem sicut potentia activa ad passivam, ut ex praedictis patet; oportet igitur utrumque esse unius generis. Cum igitur intellectus possibilis non sit secundum esse separatus a nobis sed uniatur nobis ut forma, et multiplicetur secundum multitudinem hominum, ut ostensum est, necesse est quod intellectus agens sit aliquid unitum nobis formaliter, et multiplicetur secundum numerum hominum. Moreover, agent and patient must be proportionate to each other. Examples are matter and form, for matter is reduced to act by an agent. This is why an active potency of the same genus corresponds to every passive potency; for act and potency pertain to one genus. But the agent intellect is to the possible intellect what active potency is to passive potency, as is clear from this discussion. Hence they must both pertain to one genus. Therefore, since the possible intellect has no separate existence apart from us, but is united to us as a form and is multiplied according to the number of men, as we have shown, the agent intellect must likewise be something that is united to us as a form, and must be multiplied according to the number of men. Capitulum 87 Chapter 87 Quod intellectus possibilis et agens fundantur in una essentia animae That the possible intellect and agent intellect are founded in the soul’s essence Cum autem tam intellectus possibilis quam agens nobis formaliter uniatur, necesse est dicere quod in eadem essentia animae conveniant. Omina enim quod alicui unitur formaliter, aut unitur ei per modum formae substantialis, aut per modum formae accidentalis. Si igitur intellectus possibilis et agens uniantur homini per modum formae substantialis, cum unius rei non sit nisi una forma substantialis, necesse est dicere quod intellectus possibilis et agens conveniant in una essentia formae, quae est anima. Si vero uniantur homini per modum formae accidentalis, manifestum est quod neutrum eorum potest esse accidens corpori, ex hoc quod operationes eorum sunt absque organo corporali, ut supra ostensum est; sequitur quod uterque eorum sit accidens animae. Non est autem in uno homine nisi anima una; oportet igitur quod intellectus agens et possibilis in una essentia animae conveniant. Since the agent intellect and the possible intellect are formally united to us, we must acknowledge that they pertain to the same essence of the soul. Whatever is formally united to another thing is united to it either in the manner of a substantial form or in the manner of an accidental form. If the possible intellect and the agent intellect were united to man after the fashion of a substantial form, we would have to hold that they share in the one essence of that form which is the soul, since one thing cannot have more than one substantial form. On the other hand, if they are united to man after the fashion of an accidental form, neither of them, evidently, can be an accident of the body. Besides, the fact that their operations are performed without a bodily organ, as we proved above, shows that each of them is an accident of the soul. But there is only one soul in one man. Therefore, the agent intellect and the possible intellect must belong to the one essence of the soul.