Since the 1950s several analytical philosophers have turned their attention to the study of Aquinas. Scholars such as Elizabeth Anscombe, Peter Geach, Anthony Kenny, Eleanor Stump and John Haldane have all employed Aquinas's ideas in their own philosophical projects and have made those ideas better known to English-speaking philosophy. This had two main benefits. First, it subjected Aquinas's work to the kind of logical scrutiny rarely found outside analytical philosophy. Second, it positioned Aquinas's ideas in relation to the concerns of contemporary analytical philosophy. Paul O'Grady's book Aquinas's Philosophy of Religion fits broadly within this approach and shares many of its strengths and weaknesses.
Chapters one to three are propaedeutic. The first explains why the study of Aquinas as a philosopher of religion is legitimate and desirable. It shows how Aquinas's interests fit well with those of contemporary philosophy of religion. It argues that Aquinas employed philosophy in his work and it shows that the main objections to approaching Aquinas in this way are not compelling. The second chapter discusses the context of Aquinas's work. It outlines the main intellectual sources Aquinas drew on. It tells us something of Aquinas's life and works, and it offers a succinct outline of the key philosophical principles employed throughout Aquinas's work. The third chapter explains Aquinas's views on the relationship between faith and reason. It also locates Aquinas's position in relation to the main contemporary views. Chapters four to seven are the heart of the book, though. In the fourth chapter O'Grady considers arguments for the existence of God, focusing on Aquinas's first, third, and fifth ways. The fifth chapter discusses two crucial objections to God's existence: the problem of evil and the problem of naturalism. The next two chapters analyse God's nature, focusing successively on divine simplicity and eternity (chapter six) and divine goodness, knowledge, and power (chapter seven).
There is much to admire in the book. It serves both as an introduction to Aquinas's philosophical ideas and as a way into philosophy of religion generally. O'Grady is very good at locating Aquinas's views within contemporary analytical debates. The discussions of faith and reason, of the different types of problem of evil, and of naturalism are all very helpful, as is O'Grady's explanation of the distinction between essentially and accidentally ordered causes, and even when one is not fully convinced by O'Grady's analysis its clarity and insight encourage one to think carefully about the issues which is exactly what a philosophical work should do.
Take the third way. Central to its argument is the idea if everything is contingent then at some time there would have been nothing. Critics accuse Aquinas of reasoning illicitly from the relatively innocuous claim everything contingent at some time is not to the more contentious claim at some time everything contingent is not. O'Grady's analysis focuses on two logical fallacies: the fallacy of composition which attributes to a whole features properly belonging to its parts and the quantifier shift fallacy which attributes numerically the same feature to a group of individuals each of which enjoy some feature in common. He links the two fallacies and suggests avoiding them depends upon the kind of whole one is reasoning about. Thus, if each brick in a wall is red then the wall will be red but if each child in the class has a mother, it does not follow that the class of children has a mother: walls are one kind of whole, classes another. Applied to contingent beings then, each of them has the nature of possible being; they are members of that genus and together they all form a whole. To that whole the nature of possible being can be attributed, that nature requires an antecedent, and therefore if everything were like that then there would be nothing.
But one can challenge O'Grady's analysis at various points. First, the link between the fallacies is questionable. Thus, one might agree each child in the class lacks numerically the same mother, without also agreeing the class of children is a whole to which one's ontology is committed. A fortiori do contingent beings really form a whole as O'Grady's view appears to require? Second, even if one accepted that link, the example O'Grady uses – the wall – is an artefact ultimately composed from substances and as such not a primitive entity in Aquinas's ontology. Therefore, one might take the view O'Grady's proposal works for artefacts not substances whereas it is substances which raise the problem we really need to address. Third, the notion of a genus of possible beings is problematic. In Aquinas's view no genus even one of the highest genera exhausts being so if possible being is a genus it will have to exclude some being from its reach. What might it exclude though? Presumably necessary being. Yet it is precisely the existence of necessary being the third way is supposed to demonstrate. So if the third way is to do that it cannot presuppose the existence of necessary being which it will if possible being is a genus.
However, the principal weakness of the book is its limited engagement with more historically sensitive approaches to Aquinas. Hence O'Grady's analysis of the first way would have been stronger had he considered James Weisheipl's and William Wallace's work on motion. ‘Motion in a Void: Aquinas and Averroes’, Weisheipl's contribution to the 1974 P.I.M.S. collection published to celebrate 700th anniversary of Aquinas's death, argued that Aquinas's account of motion did not depend upon resistance, whilst Wallace's 1956 The Thomist article dealt in detail with Newtonian-based objections to the first way. Similarly, Malcolm's 1979 Journal of the History of Philosophy article challenged Geach's thesis that Aquinas only availed of the inherence theory of predication. On the contrary Aquinas used the identity theory at times, particularly when discussing God e.g. ST Ia q. 13 art. 12, yet O'Grady makes no reference to this.
Still it is unrealistic to expect a book to address every topic in precisely the way its reader would wish and in the final analysis O'Grady's book is excellent. Let us hope he produces the work on Aquinas's philosophical theology he hints at near the end of this one.
