An Ontological Disproof of the Devil?

November 3, 2025 - 9 minutes read - 1898 words

If you’ve studied philosophy for a while, you’ve probably come across the ontological argument for the existence of God. This argument attempts to show that God’s existence necessarily follows from God’s essence. In other words, given God’s nature, it is impossible for Him not to exist. But did you know that the same reasoning can be used to prove the *non-*existence of the Devil? At least, if we make certain assumptions about the Devil—the primary one being that the Devil is absolutely the worst possible thing imaginable. Let’s take a look why some philosophers think that proving the existence of God might also disprove the existence of the Devil.

The Ontological Argument for God

Saint Anselm of Canterbury was responsible for the ontological argument, in its earliest form. In his work the Proslogion, which he first began to circulate in 1077-8, Anselm proposed that God’s existence follows from two fundamental truths:

(1) God is that which nothing greater can be conceived.

And,

(2) To exist is greater than not to exist.

There is of course a lot that can be said about how these assumptions are supposed to work together to prove God’s existence—indeed, discussion of the matter has occupied philosophers and theologians for almost a millennium. But the basic idea is that, if God didn’t exist, then we would be able to conceive (or we might say to imagine) a being that is greater than God. Namely, a being that has all of God’s magnificent attributes—unlimited power, knowledge, virtue, and etc.—but that also exists in reality, not just the mind alone. However, since such a being would be greater than God (given 2), he must in fact be God, since God is, after all, the greatest conceivable thing (given 1). To quote Anselm:

‘If then that-than-which-a-greater-cannot be-thought exists in the mind alone, this same that-than-which-a-greater-cannot-be-thought is that-than-which-a-greater-can-be-thought. But this is obviously impossible. Therefore there is absolutely no doubt that something-than-which-a-greater-cannot-be-thought exists both in the mind and in reality.’ (Proslogion, Ch. 2)

I know, it sounds like a lot of philosophical trickery—and it might well be. Yet while the reasoning might seem dubious, it is far from obvious why it is dubious. As Bertrand Russell once wrote in his History of Western Thought, ‘…it is easier to feel convinced that [the ontological argument] must be fallacious than it is to find out precisely where the fallacy lies.’

In any case, we’re not here to get caught up in the merits of the ontological argument per se. Let’s just suppose for a moment that it’s true (which, despite what some people might say, isn’t entirely unreasonable). What we want to know is what else follows from this reasoning. Can we also disprove the Devil?

Parodies of the Ontological Argument

The idea that we can disprove the existence of the Devil using Anselm’s logic appears in the vein of certain parodies of the ontological argument. These parodies are arguments that allege to follow the reasoning of the ontological argument, but that in doing so, lead us into absurdity. This suggests that there must be something wrong with the ontological argument, even if we can’t tell exactly what the problem is. The first and perhaps most famous of these parodies appeared almost immediately after Anselm’s work began to circulate. It is known as the perfect island argument.

This suggests that there must be something wrong with the ontological argument, even if we can’t tell exactly what the problem is.

Gaunilo of Marmoutiers crafted the argument; one of Anselm’s contemporaries and a fellow Benedictine monk. Gaunilo claims to show that, if we follow Anselm’s logic, we can prove the existence of just about any perfect thing. He asks us to imagine the case of an island that is ‘superior everywhere in abundance of riches to all those other lands that men inhabit’—so much so that the island we imagine is the greatest conceivable island (thus replicating in his own way Anselm’s first assumption). We then must ask: does this island really exist? Well, according to Gaunilo, on Anselm’s reasoning, it must exist! Why? Because if it didn’t, then we would be able to conceive of a greater island, namely, one that is just like the one we imagine, but that also exists—and, etc. Thus we have an analogy of the ontological argument that can bring anything perfect into existence, seemingly by magic. That’s a curious result, and clearly an absurd one.

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Now one of the issues with these kinds of parodies is (arguably) that they don’t quite parallel the logic of the ontological argument. They fall short insofar as it is not possible to in fact conceive of an absolutely perfect island. Whatever one imagines the perfect island to be, as the Christian philosopher Alvin Plantinga has pointed out (1974), it can always be improved upon in some way. It is always possible to add more riches and abundance (or whatever else one might want) to an island. In fact, if we were to make an island as perfect as possible, it might start to look not very much like an island at all. To keep improving the island we would end up having to attribute God like features to the island—since surely a God-like island is better than a non-God like island—until eventually we no longer have a perfect island at all, but God Himself. In other words, there’s a difference between an island’s perfection and God’s perfection. The latter, unlike the former, is absolute perfection—and it is only from absolute perfection, at least according to Anselm, that necessary existence follows. That is the perfection of God; not the limited perfection of an island. All this is to say that these parodies that claim to bring anything perfect into existence are not themselves entirely perfect. They are not (again, arguably) precise analogies of the ontological argument, meaning that they do not necessarily demonstrate that the ontological argument is flawed.

This is where we must now turn specifically to the ontological disproof of the Devil (let’s call this argument ODD). The ODD is different from the other parodies in at least two important respects. The first is that it parallels the logic of the ontological argument much more precisely. As we shall see, it deals in absolutes. The second is that it doesn’t attempt to prove the existence of anything. Instead, it attempts to disprove the existence of something—namely, the Devil. It is in this way that the ODD is unique among the parodies of the ontological argument. It is an interesting inversion of the argument, not a critical analogy.

The Ontological Disproof of the Devil

The philosopher C. K. Grant first described the ODD in his 1957 paper, ‘The Ontological Disproof of the Devil’. To open the paper, Grant writes that it is ‘remarkable’ that those who accept the ontological argument for God ‘have failed to notice that this proof also demonstrates the nonexistence of the Devil’. That is to say, if we assume that the Devil is ‘an absolutely imperfect being’ (i.e. something which nothing less great can be conceived), then we can follow Anselm’s logic to the conclusion that the Devil does not exist. We can take a moment to look at the fundamental assumptions of the two arguments side-by-side:

THE ONTOLOGICAL ARGUMENT FOR GOD

(1) God is that which nothing greater can be conceived.

(2) To exist is greater than not to exist

THE ONTOLOGICAL DISPROOF OF THE DEVIL

(1) The Devil is that which nothing less great can be conceived.

(2) To not exist is less great than to exist.

The ODD perfectly inverts the ontological argument for God. If we accept (with Anselm) that existence is greater than non-existence, then we must also accept that non-existence is less great than existence—and in turn we must also agree with whatever follows from that assumption. As Grant explains:

‘…from the idea of absolute imperfection it […] follows that any being answering to this description must necessarily be non-existent, for a completely imperfect being which exists is a contradiction in terms. In other words, if it is supposed that existence is one of the properties comprised in the concept of perfection, then nonexistence must also be a property of a completely imperfect being.’

This argument is much more closely aligned to the ontological argument than the parodies mentioned previously. The ODD stands out because, unlike the other parodies, it is unpacked in terms of absolutes. We might always be able to imagine a way to make an island more or less perfect; but we cannot imagine a way to make either God (as absolute perfection) more perfect; nor to make the Devil (as absolute imperfection) less perfect. The ODD parody is in this respect not subject to the same kind of criticism as the other parodies. It does not miss the point of absolute (im)perfection. Does that mean we should just accept that the Devil therefore does not exist? That might be too hasty.

Does that mean we should just accept that the Devil therefore does not exist? That might be too hasty.

For one thing, we can only draw this conclusion (in this way) if we also accept the ontological argument. I’ve suggested the parodies that are usually levelled against the argument are not entirely successful. But there are plenty of other reasons to think that the ontological argument fails. Kant’s famous dictum that ‘existence is not a predicate’ comes to mind.

And for another thing, there is also the question of whether we can really think of the Devil as absolute imperfection. As Grant acknowledges, the traditional view of the Devil might have him as an absolutely immoral being; but that does not mean he is imperfect in every way. The Devil might have been cast out from heaven, but he still knows things, he can still do things. It is probably therefore incorrect to say that the Devil is absolutely imperfect.

So where does that leave us? Has our discussion of these ontological arguments been for nothing? I think to say so would also be too hasty. We can at least say this: if we agree with Anselm that existing is better than not existing, then it seems to follow that total imperfection—whatever that might be, Devil or not—does not, indeed cannot, exist. That is to say, no matter how terrible this existence might sometimes seem, it can never be totally imperfect. That’s one positive message that we can all take away from the ontological disproof of the Devil, I think.

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Chris Atkinson is a postdoctoral researcher in philosophy at Hokkaido University, Japan. He has written primarily about the nature and norms of belief, as well as a bit of aesthetics. He is also interested in the history of philosophy. Previously, he taught philosophy at the University of Hong Kong, and Lingnan University, Hong Kong.

Homepage: cj-atkinson.com

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