1 Objection 1: It would seem that there is one active intellect in all. For what is separate from the body is not multiplied according to the number of bodies. But the active intellect is separate, as the Philosopher says De Anima iii, 5). Therefore it is not multiplied in the many human bodies, but is one for all men.
1 Ad quintum sic proceditur. Videtur quod intellectus agens sit unus in omnibus. Nihil enim quod est separatum a corpore, multiplicatur secundum multiplicationem corporum. Sed intellectus agens est separatus, ut dicitur in III de anima. Ergo non multiplicatur in multis corporibus hominum, sed est unus in omnibus.
2 Objection 2: Further, the active intellect is the cause of the universal, which is one in many. But that which is the cause of unity is still more itself one. Therefore the active intellect is the same in all.
2 Praeterea, intellectus agens facit universale, quod est unum in multis. Sed illud quod est causa unitatis, magis est unum. Ergo intellectus agens est unus in omnibus.
3 Objection 3: Further, all men agree in the first intellectual concepts. But to these they assent by the active intellect. Therefore all agree in one active intellect.
3 Praeterea, omnes homines conveniunt in primis conceptionibus intellectus. His autem assentiunt per intellectum agentem. Ergo conveniunt omnes in uno intellectu agente.
4 On the contrary, The Philosopher says De Anima iii, 5) that the active intellect is as a light. But light is not the same in the various things enlightened. Therefore the same active intellect is not in various men.
4 Sed contra est quod philosophus dicit, in III de anima, quod intellectus agens est sicut lumen. Non autem est idem lumen in diversis illuminatis. Ergo non est idem intellectus agens in diversis hominibus.
5 I answer that, The truth about this question depends on what we have already said Article 4). For if the active intellect were not something belonging to the soul, but were some separate substance, there would be one active intellect for all men. And this is what they mean who hold that there is one active intellect for all. But if the active intellect is something belonging to the soul, as one of its powers, we are bound to say that there are as many active intellects as there are souls, which are multiplied according to the number of men, as we have said above Question 76, Article 2). For it is impossible that one same power belong to various substances.
5 Respondeo dicendum quod veritas huius quaestionis dependet ex praemissis. Si enim intellectus agens non esset aliquid animae, sed esset quaedam substantia separata, unus esset intellectus agens omnium hominum. Et hoc intelligunt qui ponunt unitatem intellectus agentis. Si autem intellectus agens sit aliquid animae, ut quaedam virtus ipsius, necesse est dicere quod sint plures intellectus agentes, secundum pluralitatem animarum, quae multiplicantur secundum multiplicationem hominum, ut supra dictum est. Non enim potest esse quod una et eadem virtus numero sit diversarum substantiarum.
6 Reply to Objection 1: The Philosopher proves that the active intellect is separate, by the fact that the passive intellect is separate: because, as he says De Anima iii, 5), the agent is more noble than the patient. Now the passive intellect is said to be separate, because it is not the act of any corporeal organ. And in the same sense the active intellect is also called separate; but not as a separate substance.
6 Ad primum ergo dicendum quod philosophus probat intellectum agentem esse separatum, per hoc quod possibilis est separatus; quia, ut ipse dicit, agens est honorabilius patiente. Intellectus autem possibilis dicitur separatus, quia non est actus alicuius organi corporalis. Et secundum hunc modum etiam intellectus agens dicitur separatus, non quasi sit aliqua substantia separata.
7 Reply to Objection 2: The active intellect is the cause of the universal, by abstracting it from matter. But for this purpose it need not be the same intellect in all intelligent beings; but it must be one in its relationship to all those things from which it abstracts the universal, with respect to which things the universal is one. And this befits the active intellect inasmuch as it is immaterial.
7 Ad secundum dicendum quod intellectus agens causat universale abstrahendo a materia. Ad hoc autem non requiritur quod sit unus in omnibus habentibus intellectum, sed quod sit unus in omnibus secundum habitudinem ad omnia a quibus abstrahit universale, respectu quorum universale est unum. Et hoc competit intellectui agenti inquantum est immaterialis.
8 Reply to Objection 3: All things which are of one species enjoy in common the action which accompanies the nature of the species, and consequently the power which is the principle of such action; but not so as that power be identical in all. Now to know the first intelligible principles is the action belonging to the human species. Wherefore all men enjoy in common the power which is the principle of this action: and this power is the active intellect. But there is no need for it to be identical in all. Yet it must be derived by all from one principle. And thus the possession by all men in common of the first principles proves the unity of the separate intellect, which Plato compares to the sun; but not the unity of the active intellect, which Aristotle compares to light.
8 Ad tertium dicendum quod omnia quae sunt unius speciei, communicant in actione consequente naturam speciei, et per consequens in virtute, quae est actionis principium, non quod sit eadem numero in omnibus. Cognoscere autem prima intelligibilia est actio consequens speciem humanam. Unde oportet quod omnes homines communicent in virtute quae est principium huius actionis, et haec est virtus intellectus agentis. Non tamen oportet quod sit eadem numero in omnibus. Oportet tamen quod ab uno principio in omnibus derivetur. Et sic illa communicatio hominum in primis intelligibilibus, demonstrat unitatem intellectus separati, quem Plato comparat soli; non autem unitatem intellectus agentis, quem Aristoteles comparat lumini.