The Arguments of Aquinas: A Philosophical View by J. J. MacIntosh (review)

Aquinas never describes himself as a ‘philosopher.’ He typically uses that word when referring to such “pagans” as Aristotle. Yet he often presents what we can now view as purely philosophical arguments. And it is some of these with which MacIntosh is concerned in this fine new book, which is divided into three parts, as is Aquinas’s Summa Theologiae. MacIntosh has previously published two books on Robert Boyle (1627–1691), who features from time to time in the present volume.

In part 1, “Natural Philosophy,” MacIntosh reports a number of things that Aquinas has to say about necessity and possibility, causality, time and motion, and time and infinity. Part 2, “Natural Theology,” deals with Aquinas under the headings “God’s existence,” “God’s attributes,” and “Foreknowledge and freedom.” Part 3, “Human Beings,” contains chapters titled “Epistemology and philosophy of mind,” “Souls and Immortality,” and “Morality and Method: Aquinas on lying and unnatural practices.” Part 1 is largely, though not exclusively, expository. In parts 2 and 3, which also contain a fair amount of exposition, MacIntosh seems more concerned to evaluate some of the arguments of Aquinas on which he reports. And he tends to evaluate them rather favorably, though he also raises objections to some of them.

MacIntosh modestly tells us that he is not an Aquinas scholar. He describes himself as someone who admires Aquinas as a philosopher and who wishes to show contemporary philosophers unfamiliar with Aquinas that he is of philosophical importance (x). But MacIntosh clearly knows a lot about Aquinas, and his uniformly clear expositions display a serious grasp of Aquinas’s thinking. So, for instance, MacIntosh rightly notes how Aquinas, unlike Hume, takes cause and effect to be “two sides of the same coin” (34). He also well explains how causa, as Aquinas uses the word, might be best translated as ‘explanation’ (35–36). Again, MacIntosh is correct to say that “it is simultaneous causation that is primarily of interest to Thomas in the five ways” (41). I might add that I was particularly impressed by what MacIntosh says in chapter 4 concerning Aquinas on the eternity of the world. Contrary to some of his theological contemporaries, Aquinas argues that the universe could have existed without a beginning. A famous objection to this thesis holds that if the history of the world goes back to infinity, then the present could never have arrived. Yet MacIntosh neatly indicates the flaw in this objection while also noting how Aquinas put his finger on it. He also well explains how Aquinas’s view on the possibility of the universe’s never having begun to exist is compatible with what he says in Summa Theologiae, 1a,7 about the possibility of an actual infinite multitude.

Some of MacIntosh’s expositions of Aquinas are brief, and, perhaps, too brief. For example, MacIntosh might have offered more than he does when turning to what he refers to as ‘God’s attributes.’ He provides two pages (101–2) on what Aquinas thought about God, univocity, and analogy. But he does not, I think, sufficiently clarify Aquinas’s claim that reflection on “God talk” needs to take account of res significata (thing signified) and modus significandi (way of signifying). Aquinas is clear that our talk of God always “signifies imperfectly” (see Summa Theologiae, 1a,13,4). Abstracting from what he says about metaphor, he also holds that our talk of God is always somehow equivocal. I suspect that readers of MacIntosh might fail to pick up on these important facts and their philosophical implications.

Again, consider what MacIntosh says about Aquinas on divine simplicity. In this he does not provide any systematic discussion of what Aquinas means when using the word esse. But if Aquinas is wrong on what he takes to be the distinction between essence (essentia) and existence (esse), then a lot that he says about God is also wrong. Yet readers of McIntosh...