FORM. — In ordinary usage, it is the external arrangement of the parts of a body (μορφή), a quality of sensible substances, especially living beings, by which they are said to be well-formed or deformed (Aristotle, Cat., 8, 10a–12). In philosophical reflection, form (f.) denotes the principle that determines the essence and structure of being as such: it is then called the cause of things and the “species” (εἶδος) par excellence (Phys., III, 3, 194 b 26; Met., V, 2, 1013 b 23).
Form is the radical principle of the positivity of being, inasmuch as it determines the content of essence; it is the act and the “first perfection” of whatever exists, whether as simple substance (i.e., pure form) or as composite substance (the union of matter and form). To form, as ontological act, there corresponds in the logical order the “difference”: form determines and actualizes matter in reality, while specific difference determines and actualizes in the synthesis of definition the still vague content of the “genus” (Met. VII, 4, 1030 a 11 sqq.). On the one hand, therefore, form, as the distinguishing and dividing principle of genera, traverses from top to bottom the classifications of beings, isolating them in the irrefutable originality of the lowest species; on the other, as the first constitutive principle of beings themselves and the proper λόγος of their structure, form simultaneously maintains and secures the unity of being within individual substances and the unity of nature amid the multiplicity of individuals dispersed in time and space (Top., II, 2, 109 b 14).
In an intellectualist vision of the world, to which both Plato and Aristotle remain faithful,
form is thus the first principle of being, of becoming, and of knowing. The contrast between the two philosophers concerns the mode of “presence” of forms in matter: whether it occurs by way of “participation,” so that the “true” form is only one (transcendent and immaterial), as Platonism holds; or whether one must affirm the “subsistence” of forms in sensible matter and the primacy of the individual sensible substance over genera and species, as Aristotelianism maintains (Met., XIII, 3, 1070 a 18; XIV, 4, 1078 a 31). Without entering into the controversy over the proximate origin of the concept of form, it must be held that it expresses the most characteristic contribution of Aristotle to Western culture (W. Jaeger). And it truly expresses the central core of his thought, however it may be applied to analyses of nature, aesthetic, ethical, social, and political activities, and even to philosophical reflection itself. By virtue of form, Aristotelian becoming is not Heraclitean flux but the “transition” from the capacity to have a form to the actual possession of it: a transition effected by an “agent” that first possesses such a form as its own act and then as the “end” of its action. For this reason, form is the first and final perfection of being (ἐντελέχεια: De Anima, II, 1, 412 a 10; Met., V, 4, 1015 a 10).
In this way, the new concept of form tempered the excesses of Platonism and checked the advance of Democritean and Empedoclean physical mechanism by affirming the predominance, in physics and biology no less than in the development of spiritual life, of morphological and qualitative criteria over matter and purely quantitative relations. Form is therefore act, substance, and being “more than matter” (Met., VII, 3, 1020 a 29): a principle that medieval Aristotelianism expressed in the formula “forma dat esse,” though diversely understood by different schools. The followers of Avicenna extended the doctrine of universal matter and form and the multiplicity of cosmic matter and forms to a “plurality of forms” within the same individual (early Franciscan school) or, at least in the case of man, to the composition of a “form of corporeity” and of the spiritual soul (Scotus). It was within this school that the opinion took hold that matter itself possessed a certain “act,” albeit imperfect, and was not pure potency: an attitude later endorsed by Suárez and not without influence on Leibniz’s dynamism. For St. Thomas, who remains rigorously on Aristotle’s metaphysical plane, form and matter stand in the metaphysical tension of contradiction: the unity of real being depends on the unity of substantial form and is repugnant to the very divine power to attribute any act whatsoever to matter (Quodlib., III, q. 1, a. 1).
The Aristotelian viewpoint, which seemed submerged by Galilean physics, has been rehabilitated in various sectors of contemporary culture. In the ontogeny of living beings, the processes of organization obey a law that is interior to them or that has the meaning and efficacy of a form or entelechy (H. Driesch). In the development and articulation of cognitive functions, the content of objects is not given by the sum of simple elementary contents (associationism), but presents itself immediately as an organized “whole” that has the character of form (Gestalt psychology). There are visual, acoustic, tactile forms..., static forms and forms of movement: for all of them the general law holds that form is other than, or rather something more than, the sum of the parts (Ehrenfels). Yet while the apriorist position attributes forms (Gestalten) to “intellectual production” (the school of Meinong) and the hypothesis of “isomorphism” claims that perceptual forms are the univocal effect of psycho-physical processes unfolding in the cortical zone (the school of Wertheimer), neo-Aristotelians distinguish, in agreement with experience itself, between form and meaning. Form may be an immediate sensory content (“common sensibles” of Aristotle), but the meaning—which is far more important than form—belongs to the higher functions of the intelligence.
Within philosophy, Kant’s “pure a priori forms” (Denkformen) mark the deviation from the original Aristotelian concept that has proved most pregnant with consequences, even to the point of abolishing, with activist Hegelianism, the very concept of form in favor of an “act” that makes itself and knows no law outside itself. In modern historiography, “form” has come to signify the “type” of a culture or civilization (Dilthey’s Grundformen, Spranger’s Lebensformen, etc.).
Boldetti discovered in the upper part of the Domitilla cemetery a large marble slab with the epitaph of a certain Annibonus, who « fecit sibi et suis locum hominibus n. VIII intro formas ». A fragment of the slab is now in S. Maria in Trastevere. A two-place tomb was called bicandens, from scandere « to divide », tercandens « for three ».