### ABSTRACT, ABSTRACTION
**I. In general.** "Abstract" is the qualification of mental contents, ideas or universal concepts (v.), in opposition to things existing in themselves in reality, i.e., "concrete." Within the same ideal sphere, the universal reflected or logical (animalitas, humanitas... = genus and species...) may be called "abstract" with respect to the direct or metaphysical universal (animal, homo), insofar as the former expresses the mode of belonging and predication of a nature, while the latter expresses the real content of that nature according to the mode of being it has in reality. Finally, in the real sphere, "abstract" is the qualification of substances that are entirely free from commerce with matter, such as God and pure spirits: a notion already present in Plato and Aristotle and which had particular diffusion in Neoplatonic metaphysics (transcendence of the One and the Good).
In Hegel, on the contrary, "abstract" is the individual as such, which is the subject of perception ("this, here, now"), insofar as it is considered in itself outside the dialectical movement and therefore unreal; while "concrete" is the qualification of self-consciousness in that ultimate and complete form which is spirit, absolute creative freedom of itself and of its modes, corresponding to the categories (Hegel, *Vorlesungen über die Geschichte der Philosophie*, Leiden 1908, Italian trans., I, Florence 1930, p. 34 ff.).
In actualism (v.), the concrete, which is spirit, is conceived as an indefinite movement of an act never completed that is always being made and becoming: there is no pure thesis nor pure antithesis, as Hegel maintained, no being and non-being, but synthesis, that unique act which we are, thought (G. Gentile, *La riforma della dialettica hegeliana*, 2nd ed., Messina 1923, p. 207). In existentialism (v.), the concrete returns to being the individual, the existing person, and the abstract becomes the object of thought.
**2. For Plato**, the "Ideas" or universal forms and species that subsisted in themselves "separate" from the material substances of which they were the exemplars were also "real abstractions." The existence of particulars was explained by Plato through a "participation" in the Idea, and correlatively valid knowledge, which the soul seeks in science, through a direct "participation" in the same intelligibles subsisting. For Aristotle, on the other hand, natural substances imply as their constitutive principle, together with form, also matter; they are "synolon" of matter and form, where form is understood only as act and perfection of matter, since it cannot exist except in it: definition must therefore refer both to matter and to form (Metaph., VI, 1025 b, 31-1025 a, 5; V. ibid., VIII, 5, 1030 b, 14 ff.; De Anima, III, 4, 429 b, 10 ff.). From this situation two consequences followed: a) essence and form, insofar as it is united with matter, is not intelligible in itself, but manifests itself only through sensible qualities; b) the human soul, substantial form of the body, is pure potency in the order of knowing: it does not therefore have intelligibles innate in itself nor "participate" directly in them. Just as essences are intelligible in potency in sensible qualities, so the soul can unite with them in knowledge by moving from sensible manifestations: the process that effects this passage from concrete sensible to intelligible is called "abstraction."
Every passage from potency to act requires an actual principle that can move the principle that is in potency to act. In the soul, therefore, there must be two principles of understanding: one active (the agent intellect), the effective principle of the intelligible from the sensible, and the other passive (the possible intellect), receptive of the abstract intelligible (De Anima, III, 5, 430 a, 10 ff.; Sum. Theol., 1ª, q. 79, a. 1-4). The process of intellectual abstraction is accomplished in three stages: 1) the preparation of "phantasms" or sensory representations by the external and internal senses, in particular by the cogitative faculty (v.) and memory (v. C. Gent., II, 60); 2) the production, by the agent intellect, of the intelligible form ("impressed species") from the sensible forms of the phantasms, which actualizes the possible intellect; 3) the assimilation by the possible intellect of the essence thus abstracted and presented in the intelligible species, and the production—at a later moment—of an immanent term of the intellect, which is the *verbum* or inner word (species or *intentio intellecta*; C. Gent., I, 53; IV, 11). The stage in which abstraction is properly effected is the second, insofar as it is here that the passage from sensible to intelligible contents is effected.
St. Thomas explains the possibility of this passage, subjectively, insofar as sense and intellect belong to the same soul and derive from it in relations of mutual dependence (Sum. Theol., 1ª, q. 77, entire); objectively, by the complementarity between the nature of the soul and the content of the phantasm: *"Anima intellectiva est quidem actu immaterialis sed est in potentia ad determinatas species rerum. Phantasmata autem e converso sunt quidem actu similitudines specierum quarundam, sed sunt potentia immateriales. Unde nihil prohibet unam et eandem animam, in quantum est immaterialis in actu, habere aliquam virtutem, per quam faciat immaterialia in actu, abstrahendo a conditionibus individualis materiae (quae quidem virtus dicitur intellectus agens), et aliam virtutem receptivam huiusmodi specierum quae dicitur intellectus possibilis, in quantum est in potentia ad huiusmodi species"* (Sum. Theol., 1ª, q. 79, a. 4, ad 4). The collaboration between agent intellect and phantasm occurs in a twofold order of causality: first, insofar as the phantasm presents the "matter" of knowing, the object in its concrete essence that must pass into universality through the efficacy of the illumination of the agent intellect; and second, insofar as the phantasms, thus illuminated, become the "instrumental cause" by which the agent intellect impresses the possible intellect with the species of the intelligible or impressed (Quodlib., VIII, 3; Sum. Theol., 1ª, q. 85, a. 1, ad 4). This collaboration is at once the reflection and the sign of the substantial union of soul and body, and for St. Thomas it expresses the indispensable condition of all our knowing; from its very origin no less than in the use of already acquired knowledge, the intellect must refer to phantasms ("conversio ad phantasmata"), not "because it lacks intelligible essences in the phantasms" (De Anima, III, 7, 431 b; Sum. Theol., q. 84, a. 6-7). The manner, however, of this reference or conversion to phantasms, although it is formless in the initial knowledge of simple apprehension, differs for the terminal knowledge of the various orders of constituted sciences, which involve affirmations and negations and therefore explicit attributions about the mode of being of things in themselves.
**3. Insofar as it includes the pronouncement on being through affirmations and negations, abstraction belongs to judgment, and is subject to truth or falsity according as its attributions conform or do not conform to reality.** There is no subject, however, in the abstraction of simple apprehension, since it abstracts from every attribution and limits itself to presenting a content; for this Aristotle’s dictum holds: *"Abstrahientium non est mendacium"* (Phys., II, 2, 193 b, 35).
There are two principal forms of abstraction: one when the whole is drawn from the parts and a universal from the particular, as animal from man; the other when the form is drawn from matter (Sum. Theol., 1ª, q. 40, a. 3). The first includes, in different ways, the first confused cognitions and the notions of abstraction (already); the second, however, includes the fields of the sciences (Cajetan coined the terms "total" abstraction and "formal" abstraction). For St. Thomas, not every abstraction can be called a "praecisio" or separation from the starting object: this is true of the abstraction of the whole from the parts and of the singular from the universal, but not of the abstraction of form from matter, unlike those scholastics who more or less identify them (nominalism, Suárez). The divergence arose from the fact that, for these scholastics, as for the Augustinians, the first object of the intellect is the singular substance and not the universal nature, indeed the most indeterminate notion of being, as the Angelic Doctor holds. The reason for the divergence is to be found in the different metaphysical conception of act and potency, matter and form: those who attribute a certain act, whether formal or entitative, to matter and to potency, make the singular individual the object, indeed the first, of direct intellectual knowledge; hence they conceive abstraction as a separation or "praecisio" which the intellect subsequently performs within that global content.
Abstraction is opposed to "intuition" (v.). In man, it is the (external) senses that possess intuitive knowledge, inasmuch as in them sensible qualities are present in the concreteness and singularity that they have in things. For this reason, St. Thomas rejected the "agent intellect," advanced by certain averroists, and was thus able to secure the direct contact of human knowing with external reality (Sum. Theol., 1ª, q. 79, a. 3, ad 1). In a less rigorous sense, "intuition" can be said to denote the immediate grasp of first notions and first principles, and in this sense some modern Thomists speak of an "abstractive intuition," even if the term seems almost contradictory. The abstraction that leads to first notions and first judgments, since it cannot presuppose other knowledge in the soul, takes the form of an "intuition" (v.) which is, however, not scientific induction, but a process "sui generis" (Post. Anal., II, 19, 99 b, 23 ff.; Metaph., I, 1, 98 b, 28 ff.).
In a moral and mystical sense, abstraction implies liberation from the conditions and inclinations of sensibility and can take various forms, from those acquired through the exercise of temperance and ascetic detachment to those caused by a higher being and called "alienations" and "raptures," which can come from either divine or diabolical virtue, and sometimes even from particular bodily dispositions of the subject (Sum. Theol., 2ª-2ª, q. 15, a. 3; q. 175, a. 1). Abstraction caused by God constitutes the state of "ecstasy" (v.).