Archive for the ‘Hylemorphism’ Category

Hylemorphism and Modern Science

February 5, 2009

Thomas Aquinas wrote two books: De Principiis Naturae (circa 1252) and De Mixione Elementorum (1273), where he discusses the question of the composition of natural things or physical substances¬† (whether out of matter and form, or out of the elements). The object of the De Principiis Naturae is to account for generation, that is, the process through which all natural things are brought into existence. Aquinas identifies three principles: matter, form, and privation. Form, the actuality of matter, is a per se principle that is found only in the terminus ad quem of generation. As such, it is a differentiating principle which must be distinguished from the “essence,” for whereas the substantial form differentiates the end term of a radical change from the beginning term, the essence differentiates the end term from nothingness”. It is not the form itself which has existence, it is the composite which exists “through the form” . A form never comes to be as a subsisting thing but only as that by which the subsisting thing subsists. Forms are “educed” (eductae) from the potency of the elements into the actuality of the composite. Eduction (by contrast with generation or creation) designates the potentiality of already informed matter to receive a new substantial form. Matter and privation, on the other hand, are found together in the terminus a quo, for what can be (matter) is not what it can become (privation). Privation (a principle per accidens) is not, however, mere nothingness (otherwise we would have creation, not generation) but determinate non-being; the non-being of that which is in potency, a non-being which is as well as a being which is not” . This is why the matter which is found together with privation cannot be prime matter but determinate elemental matter. Finally, privation leads Aquinas to distinguish principles from causes along the distinction of generation and existence. Form and matter are both principles and causes because both are intrinsic causes of the “existing” substance. Yet whereas all causes are principles, all principles are not causes, for privation does not account for the existence but for the “coming to be” of substance.

The De Mixione Elementorum answers the question: “how do elements remain in a mixed body?” . Elements are natural bodies indivisible into species diverse from their own. As such, they are not only material but also efficient causes. The elements cannot remain with their substantial form in a mixed body, for otherwise such a body would rather be a juxtaposition of substances. Since a mixed body differs in kind from its constituents, it must have a substantial form of its own. Aquinas’ resolution is that the elements remain with respect to power, not with respect to their forms. A complex body is a mixio in which the qualities of the elements affect and alter each other so as to remain virtually (that is, as retrievable powers) but not actually (without a corresponding substantial form).

We can draw a parallel with modern physics. For a time, modern physics was thought of as atomistic, thus unable to accept the idea of mixio, as Aristotle and Aquinas understood it. In a chemical combination for instance, the elements were thought to remain intact at the atomic level. This view is now challenged, however, and science must make room for a conception of both the elements and the mixed bodies. The quarks, which survive in a proton, do not retain their substantial form–they have been corrupted with respect to what they actually are, as determined by their substantial forms. But they have not been corrupted with respect to what they can actually do, i.e. with respect to their powers. Further, we can propose an analogy between the concept of prima materia and neutrinos (the electron neutrino is understood as having no electric charge, no strong force, no spatial extent, no electromagnetic force, and possibly no mass).

We should avoid a common misrepresentation, namely that (1) hylemorphic composition is not to be understood as a juxtaposition of preexisting and unrelated principles (matter and form) but that (2) hylemorphism can account for the unity of natural substances, and (3) reconcile this unity with the reality of the autonomous movement of nature toward its end.

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