Aquinas: Form and Matter

Prime Matter Pluralism (PMP) states that while the prime matter of all terrestrial bodies is the same, there is a unique prime matter for each celestial body. Prime matters are distinct in virtue of being in potentiality to different forms. Steven Baldner argues that although Thomas Aquinas endorsed PMP in Summa theologiae I, he ultimately rejected it in his De caelo commentary and De substantiis separatis. Besides exegetical evidence for this claim, Baldner presents a philosophical objection to PMP: according to (...) PMP, distinct prime matters are restricted in their respective potentialities; such restriction requires form, however; therefore, prime matter is not pure potentiality. Since prime matter is pure potentiality, PMP is false. Pace Baldner, I argue that Aquinas endorses PMP as heartily in the later works as in STh I. Moreover, he resisted substantially the same objection to PMP as Baldner’s several times. In particular, Aquinas repeatedly rejected the claim that the restriction of prime matter’s potentiality requires form. In that case, when Aquinas calls prime matter “pure potentiality,” he means that it is formless of itself, not that it is in potentiality to any form whatsoever. (shrink)

Aristotelians traditionally motivate the doctrine of first (“prime”) matter by claiming that substantial change requires a subject. Without gainsaying that motivation, I propose another: first matter is a necessary postulate for the sort of unity proper to a substance. This motivation arises if one examines a claim that Patrick Toner and Robert Koons share: (TM′) the possession of emergent causal powers is necessary for substancehood. I first explain how TM′ represents the application of “Merricks’s Dictum” (“For a macrophysical object to (...) exist is to have causal powers”) to an Aristotelian framework. Next, I argue that, as Toner’s and Koons’s respective theories use TM′, it is incompatible with the denial that substances have substances as proper parts. In Toner’s hylomorphism, TM′ entails that an entity’s matter and form are independent substances. As part of Koons’s theory, TM′ implies that an entity’s elementary parts are substances. Happily, a hylomorphist need not accept TM′. For example, Aquinas rejects TM′ as incompatible with the doctrine of first matter. An ontology like Aquinas’s that includes first matter navigates the dialectical straight between the dualism and atomism. If she commits to first matter, the hylomorphist can deny that substances have substances as proper parts. (shrink)

The 16th and 17th centuries witnessed a philosophical shift that would help pave the way for modern science, a shift from metaphysical theories of material objects to other views embracing only the empirically-accessible parts of material things. One much-debated topic in the course of this shift was regarding prime matter. The late scholastic Jacobus Zabarella (1533-1589) arrived upon his views about prime matter via his version of the regressus method, a program for a sort of scientific reasoning. In his De (...) rebus naturalibus, Zabarella defends the position that prime matter is extended. However, it is less clear how he accounts for its extension. There is an important text where he apparently suggests that prime matter is extended in and of itself. However, there are two other texts apparently stating that matter is extended in virtue of a distinct accident in the category of quantity. I argue that a decisive reading based solely upon any particular texts is not available. Nevertheless, examining Zabarella’s writing on the topic as a whole, the trajectory of his overall argument is remarkably sympathetic to Averroes, who famously took the accidentally quantified position. Thus, from this systematic feature, the accidentally quantified reading is more reasonable. (shrink)

In this paper I argue that both defence and criticism of the claim that humans act ‘under the guise of the good’ neglects the metaphysical roots of the theory. I begin with an overview of the theory and its modern commentators, with critics noting the apparent possibility of acting against the good, and supporters claiming that such actions are instances of error. These debates reduce the ‘guise of the good’ to a claim about intention and moral action, and in so (...) doing have become divorced from the theory's roots in classical and medieval philosophy. Aristotle and Aquinas’ ‘guise of the good’ is primarily a metaphysical claim resting on the equivalence between actuality and goodness, from which conclusions about moral action are derived. I show the reasoning behind their theory and how it forms the basis for the claims about intention and action at the centre of the modern debate. Finally, I argue that the absence of its original foundation is apparent in recent attacks on the ‘guise of the good’. It is unsurprising that modern action theory and ethics have not always been able to comfortably accommodate the ‘guise of the good’; they are only telling half of the story. (shrink)