I begin with confession: I do not know if the five ways of St Thomas Aquinas succeed as proofs for the existence of God. I lack the competence (and can confidently say, will always lack the competence) to offer an opinion. I have read a fair bit about them. On some days one or more of them persuade; on other days they do not. But more importantly, philosophers who do have the necessary competence disagree among themselves about both their validity and soundness. My interest, however, lies not with the particulars of each proof but with their overall intent—the identification of, in Frederick Bauerschmidt’s phrase, “the self-insufficiency of the world” (Thomas Aquinas, p. 95). Thomas believes that if we attend to the beings of the world we will apprehend their radical contingency and will therefore know that there is a self-existent Creator. His proofs invite us to contemplate the world under five aspects—motion, change, perishability, perfection, and teleological movement. Thomas is convinced that when we do so we will see what he sees, namely, a world that cannot account for its existence. Etienne Gilson puts it this way:
To say that an existing thing requires an extrinsic cause of its existence is to say that it does not contain it in itself. From this point of view, the proofs of the existence of God consist in constructing a chain of causes which binds all beings which are by another to the one being who is by itself. Beings by another, which have not in themselves the wherewithal to exist, are those same things whose essence … is distinct from their existence, as opposed to being by itself whose very essence is to exist. We can say, therefore, that all the Thomistic proofs for the existence of God amount, in the last analysis, to a search beyond existences which are not self-sufficient, for an existence which is self-sufficient and which, because it is so, can be the first cause of all others. (The Christian Philosophy of St. Thomas Aquinas, pp. 80-81)
What is this ontological insufficiency of which Bauerschmidt and Gilson speak? The material entities of the universe, considered both individually and as a totality, might not and need not have been: they do not contain within themselves the metaphysical necessity of their existence. They are, in this precise sense, contingent. Rocks, snails, antelopes, mosquitos, meteors, quarks and quasars—we may describe their natures, but of each we are forced to distinguish between their essence and their existence. Existence is not included in their definition. Regarding none of them do we find ourselves declaring, “In every possible world they had to be.” Human beings are “rational animals,” Aristotle tells us; he does not then go on to say, “and they must also exist.” Contingent beings are incapable of providing a metaphysical explanation for their actuality, for the fact that they exist instead of not existing.
At the end of all our scientific investigation and analysis, we may still ask of the world, why? In the five ways, explains Bauerschmidt, Aquinas “wishes to demonstrate that what we know about the world still leaves us with the question ‘Why is there anything at all?’ and that the answer to that question is what people commonly call ‘God.’ This is, in a sense, a fairly modest project. Thomas is simply trying to demonstrate that the question ‘Why?’ is legitimate not simply in reference to this or that thing, but in reference to everything; and it is legitimate because it is a question that has an answer (in the way that a question like ‘Is the sofa sad?’ does not)” (Holy Teaching, p. 50, n. 25). Why?—is there any question more human, more universal? Have you not stood outside late at night and looked up at the stars in wonder? And if at that moment you did not know with certainty that there was a God, did you not at least hear the universe posing the question, Why is there anything, why not nothing? But how do we know that there is an answer? and if we do not know the answer through syllogistic reasoning, then how?
In his classic works He Who Is and Existence and Analogy, Eric Lionel Mascall advances what I find to be a satisfying Thomistic position. He agrees with Gilson and Bauerschmidt that the purpose of the five ways is to illumine for us the radical contingency of the universe:
As I see it, the ultimate function of the Five Ways is to make it plain, by calling attention to five outstanding features of finite being, what the fundamental characteristic of finite being is. And that fundamental characteristic is a radical inability to account for its own existence. In other words, finite being is being in which essence and existence are really distinct; in which, therefore, existence is not self-maintained but is received from without and, in the last resort, is received from a being whose existence is not received but is self-inherent. The Five Ways are therefore not so much five different demonstrations of the existence of God as five different methods of manifesting the radical dependence of finite being upon God, of declaring, in Dom [Mark] Pontifex’s phrase, that the very essence of finite being is to be effect-implying cause. (Existence and Analogy, p. 71)
Thomas presents each of his five ways in the form of demonstratio quia—an argument that moves from a perceived effect to an unperceived cause. Where there’s smoke, there’s … if not fire, then some other something causing the smoke. An effect implies a cause. To know the world truly, therefore, is to know it as an “effect-implying cause.” But Mascall is not convinced that the five ways succeed as arguments. Consider the following syllogism (modus ponendo ponens):
Major premise: If there is a contingent being, there is a necessary being;
Minor premise: But there is a contingent being;
Conclusion: Therefore there is a necessary being.
The argument is valid, says Mascall, but also misleading: “For it is only through perceiving contingent being that we can be brought to affirm the major premiss; and the minor premiss having thus been given, the conclusion is given too” (The Openness of Being, pp. 111-112). Everything hinges, therefore, on our apprehension of beings in their radical contingency: “If we perceive finite beings as they actually are, we shall perceive them as the creatures of God. And if we do so perceive them sub ratione creaturarum, we shall in perceiving them recognize the existence of the God whom we cannot perceive” (He Who Is, p. 74). The reality of God is given in the recognition of beings as creatures, or as Mascall elsewhere expresses it, in the “contuition of God-and-the-world-in-the-cosmological-relation” (The Openness of Being, p. 111). We grasp Creator and creature in one cognitive act, or we do not grasp them at all. Ultimately, we must speak not of logic but of sight. If the five ways of Aquinas work, it is only because they have helped us to apprehend reality as it truly is:
We can, of course, put the argument from finite to infinite in a syllogistic form, but when we do so we are not so much describing the process by which we have passed from the recognition of the finite to the affirmation of the infinite as convincing ourselves that the transition was not in fact unreasonable. The transition itself was made in the recognition that being whose essence is really distinct from its existence declares by its very existence the creative activity of God. In other words the primary requirement if we are to pass from the recognition of the finite to the affirmation of the infinite is not that we shall be skilled in the manipulation of Aristotelian logic but that we shall grasp in its ontological reality the act by which finite existents exist. And then we shall affirm God by recognizing him. We shall affirm him not, as ontologists affirm, in his naked reality, but as the primary agent of the act by which finite beings exist; in Dr. [Austin] Farrer’s phrase, we apprehend him in the cosmological relation and not in abstraction from it. There is one act of intellection in which we recognize both the real distinction of essence and existence in the finite existent and also its dependence upon the being in which essence and existence are identical. (Existence and Analogy, pp. 78-79)
Is Mascall’s proposal of a contuition of God in the cosmological relation a plausible reading of Thomas Aquinas? Philosopher Peter Geach thinks not. “I cannot make any sense of this metaphysical vision,” he comments; “neither, I suspect could Aquinas” (God and the Soul, p. 77). He also argues that the Neo-Thomist understanding of necessity and contingency is alien to the thought of the great scholastic. According to Aquinas, contends Geach, “contingent beings are beings liable to corrupt, break up, or the like, and necessary beings are beings with no such inner seeds of their own destruction” (p. 77). By these definitions, tomato plants and human beings are obviously contingent; angels and souls, necessary. Perhaps Geach is correct about Thomas, yet Mascall’s proposal of metaphysical contuition makes sense both of Thomas’s rational certainty in the existence of God and of that experience of wonder intrinsic to our humanity. “It is not how the world is that is mystical,” states Wittgenstein, “but rather that it is“ (Tractatus 6.44).
The contuition of the Infinite in the why of the world—have we here reached that point where metaphysics and theology meet in mirthful union?