Aquinas: Actuality and Potentiality

It is universally acknowledged that, for St. Thomas, there is a distinction between human persons or supposits and their natures or essences. But it is usually thought that there is no parallel distinction between the angelic person or supposit and its nature. Yet, as this paper argues, Aquinas consistently puts forward just such a distinction. This paper surveys Aquinas’s arguments for the unique identity of God with his essence and the corresponding distinctions between created persons and their essences, showing in (...) the process how the distinction found in angels differs from that found in material substances. It is important to recognize the distinction between supposit and nature in angels not only for its own sake as it touches on his understanding of created persons—human or angelic—but also insofar as it sheds light on Aquinas’s understanding of divine simplicity and of other act-potency compositions in creatures. (shrink)

Reconciling the permanence of existence with the existence of change is a long-standing metaphysical puzzle. Some, following Aristotle, resolve this tension by positing ‘prime matter’, a bedrock which grounds all change. Saint Thomas Aquinas argued prime matter had to be purely potential, thus completely indeterminate and extensionless. This article charitably reconstructs and critically assesses Aquinas’ view, arguing it is far too restrictive. Prime matter need only be maximally potential and determinable, allowing it to take on certain determinate properties. I argue (...) extension is an obvious candidate property and propose five theories positing extended prime matter: (1) a subtle revision of Aquinas' own view, (2) a hylomorphic approach which attributes to prime matter an ‘elastic’ extension, (3) a minimally/infinitesimally extended prime matter inspired by ancient atomism and late-renaissance/early-modern corpuscularianism, (4) a maximally/infinitely extended prime matter influenced by Advaita Vedanta, and (5) a pluralist approach reminiscent of Aristotle's elements. Crucially, by allowing prime matter a determinate characteristic, each proposal demystifies Thomistic prime matter which one could otherwise charge with being so characterless as to slip into the ‘nothingness’ which terrified the Eleatics and motivated the introduction of prime matter in the first place. (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)

A lean hylomorphism stands as a metaphysical holy grail. An embarrassing feature of traditional hylomorphic ontologies is prime matter. Prime matter is both so basic that it cannot be examined (in principle) and its engagement with the other hylomorphic elements is far from clear. One particular problem posed by prime matter is how it is to be understood both as a principle of individuation for material substances and as pure potency. I present Thomas Aquinas’s way of squeezing some intelligibility out (...) of prime matter by modeling it on the idea of logical genus. Such a modeling provides insight into understanding prime matter as substratum, as maximally indeterminate, and as ontologically vague. One of the unusual but exciting things that fall out from this analysis of prime matter is the Entirety Thesis: “For any substance x, if x has prime matter then the prime matter of x is the same* as x,” where ‘same*’ is understood as “indeterminately identical.”. (shrink)