Intelligible species
| Latin | species intelligibilis |
|---|---|
| Locus in Aquinas | Summa theologiae I, q. 85, aa. 1–2 |
| Branch | Philosophical anthropology |
| Controlling authority | Catechism 355–384; Council of Vienne; Thomistic synthesis |
| Doctrinal standing | Spiritual intellectual knowledge is implied by doctrine of the soul; the species as medium quo is Thomistic psychology |
| School | Thomism |
Intelligible species is, in Thomism, the immaterial likeness by which the intellect understands a nature, abstracted from phantasms and not itself the object primarily known.[1]
Abstraction from individual matter
Summa theologiae I, question 85, article 1, asks how the intellect understands corporeal things. The human intellect is not the act of a bodily organ, yet it is a power of a soul that is the form of a body. Its connatural object is therefore a form existing in individual matter, but not as existing in this matter. To know what is in individual matter not as in this matter is to abstract the form from the individual conditions represented by phantasms.[1]
The abstraction is not a lie. The intellect would err if it judged that the nature of a stone exists apart from matter, as Plato held. It does not err when it considers the specific nature without considering this flesh and these bones, just as sight considers color without considering the apple's smell. Common sensible matter, such as flesh and bone as such, remains in the human species as understood. Designated matter is left aside.
That by which, not that which, is understood
Article 2 closes a fatal shortcut. Some said the intellect knows only the impression made upon it, so that the species would be what is understood. Aquinas answers that then every science would be about impressions in the soul, and contradictories could both be true because each would report its own modification. The species is related to the intellect as that by which it understands, as the sensible likeness is that by which sense perceives, not the object perceived.[1]
The thing understood is in the intellect by its likeness. On reflection the intellect can know both its act and the species. Primarily, however, it knows the nature of the stone, not a mental token. Words signify what the intellect forms for judging of external things, not the species themselves as a private language. This is the school's defense of realism against both Platonism and a proto-idealism of impressions.
Agent intellect, phantasm, and retention
The agent intellect abstracts the species; the possible intellect is informed by it. Question 84, article 7, still requires a turn to phantasms for actual consideration of material natures. Question 79, articles 6–7, allow intellectual memory as retention of species without a distinct power from intellect: the species can be in potency, in full act, or in a middle habitual state. Avicenna's claim that species vanish when we cease to think is refused.[2][3]
The 1913 article on intellect describes this as the common Catholic development of Aristotle: the intellect divests the object of individuating conditions and generates an intellectual form. The Council of Vienne's definition of the soul as form of the body is the dogmatic frame. Species language does not mean that little images are affixed to a disembodied spirit. It names how a bodily person truly knows universals.[4]
Limits of the school tool
Catholic doctrine requires that we know extra-mental being, that the soul is spiritual, and that science of natures is possible. It does not define species intelligibilis. Later scholastics disputed the number of species, their remaining after the act, and the precise causality of the agent intellect. Those are school questions. Aeterni Patris commends the psychology because it keeps knowledge from collapsing into sensation; it does not freeze every manual diagram.[5]
The opposite errors are equal. One treats the species as a screen that hides the world. The other denies any immaterial likeness and cannot explain universal judgment. Thomism holds the middle: a real world, a spiritual power, a likeness that is means rather than wall. Fides et Ratio's defense of the mind's capacity for being is served by that middle even when the Latin word is left in the classroom.[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 85, articles 1–2 — Primary analysis of abstraction from phantasms and of the intelligible species as that by which the intellect understands, not that which is primarily understood.
- 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 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 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.
- 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.