Active intellect
| Latin | intellectus agens |
|---|---|
| Locus in Aquinas | Summa theologiae I, q. 79, aa. 3–5 |
| Branch | Philosophical anthropology |
| Controlling authority | Council of Vienne; Catechism 355–384; Dei Filius; Thomistic synthesis |
| Doctrinal standing | The spiritual intellectual soul is doctrine; the agent intellect as an individual power of abstraction is Thomistic psychology |
| School | Thomism |
Active intellect is, in Thomism, the soul's own power of abstracting intelligible forms from phantasms, a participated likeness of uncreated light rather than one separate intelligence shared by all men.[1]
Making the potentially intelligible actually so
Material natures as they exist in bodies are not actually intelligible. Color is actually visible; the nature of a horse, as individuated in flesh and bone, is not actually thinkable until the conditions of this matter are set aside. Thomas Aquinas therefore assigns, on the side of the intellect, a power that makes things actually intelligible by abstracting the species from material conditions. In Summa theologiae I, question 79, article 3, he takes Aristotle's comparison of this power to light as a real need in the soul, not a metaphor for attention.[1]
Without such a power, either Platonic separate forms would have to be the objects of human science, or the possible intellect would have to receive actually intelligible species from a separate intelligence. Aquinas rejects both. The senses present phantasms. The agent intellect illuminates those images and abstracts the intelligible likeness that informs the possible intellect. The 1913 Catholic Encyclopedia's article on intellect records this as the common Catholic reading of the Aristotelian pair, against Arabian monopsychism.[2]
A power in the soul, not one mind for the species
Question 79, article 4, locates the agent intellect in the soul. What is intellectual by participation, mobile, and imperfect presupposes a higher intellect that is such by essence. The soul therefore derives its intellectual light from God, according to the psalm that the light of the Lord's countenance is signed upon us. That derivation does not make the agent intellect identical with God, nor a cosmic intellect that thinks in us. Each human soul has the power whereby it lights up phantasms, because we experience ourselves abstracting universals from particulars.[1]
Article 5 then denies that there is one agent intellect numerically the same in all men. If the power belongs to the soul, it is multiplied with souls. Agreement in first principles proves a common species and a common source of light, not a shared organ. Averroes's unity of the intellect, which would dissolve personal immortality of understanding, is therefore refused as incompatible both with experience and with the faith that each person knows, merits, and is judged.
Phantasms, possible intellect, and the body
The agent intellect does not replace the senses. Question 84, article 7, requires the intellect still to turn to phantasms even after it possesses species, because the connatural object of the embodied intellect is the quiddity of a material thing. Abstraction is not a transfer of the same form from imagination into mind as if a picture were moved from one room to another. It is the production, by the agent intellect, of a likeness that represents the specific nature without individual conditions.[3]
The possible intellect receives that likeness. The two are not two little persons inside the head. They are two powers of one intellectual soul, which the Council of Vienne defined as of itself and essentially the form of the body. Catechism 355–384 receives that anthropology: the human person is a unity of body and soul, and spiritual operations of knowing and willing belong to that one subject. The school analysis of agent and possible intellect is the Thomistic map of those operations.[4]
Doctrinal core and school thesis
Catholic doctrine requires a spiritual intellectual soul, personal responsibility, and the natural knowability of truths about God and the moral law, as Dei Filius teaches. It does not define the vocabulary of intellectus agens. Aeterni Patris and Fides et Ratio commend Aquinas as a master of this psychology without making every commentator's refinement a canon. Other Catholic schools may describe abstraction with different technicalities provided they do not reduce the intellect to a bodily organ or dissolve personal understanding into a world-soul.[5]
The agent intellect is a school name. The truths it protects are not optional: natures are truly known, not only private impressions; knowledge begins from the senses without being imprisoned in them; and the light by which the intellect understands is a gift in the creature, not a fragment of the divine essence. Humani Generis later warned against discarding such scholastic principles as obsolete. The warning is a commendation of metaphysical realism, not a new definition of De anima III.[6]
References
- Back to citation occurrence 1.0 Back to citation occurrence 1.1 Back to citation occurrence 1.2 Thomas Aquinas, Summa theologiae I, question 79 — Primary treatment of the intellectual powers, including the possible intellect, the agent intellect as a power in the soul, speculative and practical intellect, and synderesis.
- Back to citation Catholic Encyclopedia (1913), Intellect — Public-domain scholastic survey of intellect as a spiritual cognitive power, including the Aristotelian-Thomistic distinction of agent and possible intellect.
- Back to citation Thomas Aquinas, Summa theologiae I, question 84 — Primary account of intellectual knowledge of bodies, the turn to phantasms, and the interpretation of Augustine on knowing in the eternal types.
- Back to citation Catechism of the Catholic Church, 355–384 — Authoritative anthropology of the human person as a unity of body and soul, with the soul as the form of the body and the principle of spiritual operations.
- Back to citation First Vatican Council, Dei Filius — Dogmatic constitution on God the Creator, the natural knowability of God, the distinction and harmony of natural and supernatural orders, and the gratuity of revelation.
- Back to citation Leo XIII, Aeterni Patris — Encyclical restoring Christian philosophy in the school of Thomas Aquinas while distinguishing that commendation from a definition of every Thomistic thesis.