Unpacking Ontological Arguments (A-Level Philosophy)
While cosmological and teleological arguments are a posteriori because they rely upon observation and experience, ontological arguments are a priori and analytic, meaning they rely on pure reason and the very definition (or concept) of "God". Essentially, ontological arguments claim that simply by understanding what we mean by "God," we can logically prove his existence. In this article, expert tutors break down three influential versions of the argument (by Anselm, Descartes and Plantinga) and evaluate some key objections.
This blog is designed to be a comprehensive resource for A-level Philosophy exams. Additionally, it will be valuable for undergraduate students studying the philosophy of religion.
St. Anselm's Ontological Argument (Proslogion, 11th Century)
Anselm was an influential theologian who served as the Arch Bishop of Canterbury between 1093 and 1109. In the Proslogion, he famously defines God as "a being than which nothing greater can be conceived" (aliquid quo nihil maius cogitari potest) and argues that denying God’s existence entails a logical contradiction. His argument can be rendered as follows:
It is a conceptual truth (or true by definition) that God is a being than which none greater can be imagined.
God exists as an idea in the mind.
A being that exists as an idea in the mind and in reality is, other things being equal, greater than a being that exists only as an idea in the mind.
Thus, if God exists only as an idea in the mind, then we can imagine something that is greater than God (that is, a greatest possible being that does exist).
But we cannot imagine something that is greater than God (for it is a contradiction to suppose that we can imagine a being greater than the greatest possible being that can be imagined.)
Therefore, God exists.
Anselm’s ontological argument thus hinges on two key ideas. First, we can conceive of a being with all perfections—every property that makes a being 'greater.' Second, existence is itself a perfection. Therefore, the very idea of a perfect being implies its existence. If a being had all perfections but didn't exist, it would lack the perfection of existence, which contradicts its perfect nature, therefore God must exist. In A-level Philosophy exams, it is useful to outline this argument in standard form (as shown above) and refer back to specific premises throughout your essay.
Gaunilo's Objection
Gaunilo of Marmoutier, a contemporary of Anselm, posed a significant critique. His concern surrounds whether Anselm's argument improperly transitions from the concept of an idea to the actual existence of something corresponding to that idea. In other words, is Anselm simply defining things into existence? To demonstrate his concern, Gaunilo formulates an analogous case of a perfect island called ‘Piland’, showing that Anselm's logic could be used to argue for the existence of absurd or nonexistent entities. Gaunilo's island approach is thus a reductio ad absurdum argument: a method of disproving a premise by demonstrating that it leads to an absurd or illogical conclusion when applied to a different, analogous case. His argument can be summarised as follows:
It is a conceptual truth that a piland is an island than which none greater can be imagined (that is, the greatest possible island that can be imagined).
A piland exists as an idea in the mind.
A piland that exists as an idea in the mind and in reality is greater than a piland that exists only as an idea in the mind.
Thus, if a piland exists only as an idea in the mind, then we can imagine an island that is greater than a piland (that is, a greatest possible island that does exist).
But we cannot imagine an island that is greater than a piland.
Therefore, a piland exists.
However, some philosophers contend that Gaunilo's "perfect island" argument fails because premise 1 is incoherent. The qualities that make up a perfect island, like fruit abundance, have no intrinsic maximum—you can always imagine more. This differs from Anselm's concept of God. Properties like perfect knowledge and power do have maximums (knowing all truths, doing all possible things). Anselm's argument works, if at all, only for concepts with properties that have such maximums. If God's essential properties lacked these, the concept would be incoherent, like Gaunilo's island. But properties like omnipotence, omniscience, and moral perfection do have maximums, so Anselm's idea of a greatest possible being avoids this issue.
Aquinas’ Objections
St. Thomas Aquinas, known for his cosmological arguments, raised two key objections to Anselm's approach to the existence of God. First, Aquinas questioned the initial premise, noting that societies have diverse concepts of God. Anselm's argument might only persuade those with a particular monotheistic definition of God. A polytheistic society unfamiliar with the God of classical theism may reject premise 1 of Anselm’s reasoning. However, this argument from cultural relativism can be addressed simply by replacing "God" with "a being than which none greater can be conceived." This restatement makes the argument accessible to any rational agent capable of understanding the concept and still arrives at the same conclusion. Thus, Anselm can easily avoid Aquinas’ first objection.
Secondly, Aquinas raised concerns about the concept of "a being than which none greater can be imagined," suggesting we might not truly grasp its meaning. While we understand finite concepts, an infinite being is beyond full comprehension. However, needing absolute understanding might not be necessary. Just as we recognise there's no largest natural number without fully comprehending infinity, a basic understanding of a maximally great being could suffice for the argument to function, provided the concept is logically sound. Essentially, a comprehensive grasp of God's nature isn't required for Anselm's argument to hold. Both of these objections are commonly skipped over by A-level Philosophy teachers, but they can be usefully applied to the Metaphysics of God section of the exam.
Kant's Objection
So far, the objections to Anselm’s ontological argument have failed to provide a killer blow. In the Critique of Pure Reason, however, Kant offers a famous objection which is often seen to refute Anselm’s position. Kant argues that "existence" isn't a property (or predicate) like being "loving" or "powerful." We can talk about a loving God, but saying "God exists" doesn't add another quality to God. Instead, it just affirms that the being with those qualities actually exists. Think of it this way: saying "the apple is red" adds the property of "redness." But saying "the apple is" simply says there's an apple with its existing properties. In simpler terms, Kant argues that existence is a precondition, not a quality. A nonexistent thing can't have any qualities at all. You can't be "red" if you don't exist to be red! So, existence isn't something that makes a being "better" – it's necessary for anything to have qualities in the first place. Existence is logically prior to properties because properties presupposes existence.
Kant's challenge thus throws a wrench in the idea that existence is a "great-making" property. And if existence doesn't automatically make something better, ontological arguments for the existence of God falls apart. Norman Malcom has also questioned whether existence makes something ‘greater’. Imagine saying a house is better if it exists. It makes more sense to say it's better if it's insulated. Or consider a person – being honest makes them better, not simply existing. Is a loving being that exists really better than a loving being that doesn't? Some might argue it's better for us if God exists, but that's different from saying existence itself makes God greater.
Descartes' Ontological Argument (Meditations on First Philosophy, 17th Century):
Like Anselm, Descartes focuses on the essential properties of God. He argues that, just as the concept of a triangle necessarily includes having three angles that sum to 180 degrees, the concept of God as a supremely perfect being necessarily includes existence as one of its perfections. A being lacking existence would not be supremely perfect, therefore God must exist. The argument can be summarised as follows:
God is a supremely perfect being.
Existence is a perfection.
Therefore, God possesses the perfection of existence.
Therefore, God exists.
However, Descartes' ontological argument faces challenges, notably Kant's objection. A key issue lies within premise 2, which posits that existence is a property or predicate that contributes to a thing's perfection. Kant, we have seen, argues that existence is not a predicate in the same way that other attributes are. Consequently, if existence isn't a property that can enhance perfection, then Descartes' argument falters.
Plantinga's Modal Ontological Argument (The Nature of Necessity and God, Freedom and Evil, 1970s):
Plantinga's argument centres on the concept of a maximally great being. Imagine the absolute pinnacle of existence – a being that possesses every conceivable perfection to the highest degree. This includes omnipotence (all-powerful), omniscience (all-knowing), perfect goodness, and a crucial element: necessary existence.
Necessary existence isn't just about being real; it's about existing in every possible world. Think of it as a fundamental truth, like 2+2=4, which holds true regardless of how reality might have been different. Plantinga's argument, in simplified form, goes something like this:
It is possible that a maximally great being exists. This is the crucial starting point. Plantinga doesn't claim to prove this possibility, just that it's a coherent and non-contradictory idea.
If it is possible that a maximally great being exists, then there is some possible world where such a being exists. This follows directly from the definition of possibility within modal logic.
A maximally great being, by definition, possesses maximal excellence in every possible world. This is where necessary existence comes in. True maximal greatness isn't contingent; it's inherent across all realities.
Therefore, if a maximally great being exists in any possible world, it exists in all possible worlds, including our actual world.
Conclusion: A maximally great being (God) exists.
What makes Plantinga's argument so intriguing is its reliance on the possibility of God's existence. He doesn't try to argue that we can observe God or deduce God's existence from the world. Instead, he focuses on the conceptual coherence of "maximal greatness." If we can even conceive of such a being without logical contradiction, then, according to modal logic, its necessary existence kicks in, guaranteeing its actuality in every possible world (including our own).
Objections:
Plantinga's argument, while original and logically structured, is far from universally accepted. The main points of contention revolve around the initial premise:
The Unproven Possibility: Critics argue that simply asserting the possibility of a maximally great being isn't enough. The burden of proof lies with demonstrating that this concept is indeed coherent and doesn't contain hidden contradictions. Just because we can string words together doesn't mean the concept they form is logically sound.
The Power of Conceivability: Is our ability to conceive of something a reliable guide to its possibility? The history of philosophy is littered with seemingly conceivable ideas that turned out to be logically impossible.
Parody Arguments: Philosophers have crafted similar modal arguments for the existence of absurd entities (like a maximally great unicorn) by simply defining them as necessarily existing and possessing maximal versions of certain properties. This raises the question of why Plantinga's argument works for God but not for these other concepts. Note the similarity of this charge to Gaunilo's ‘perfect island’ objection to Anselm.
Conclusion: Application to Essays and Exams
When approaching the ontological argument A-Level Philosophy exams, strategy is key. A common pitfall is to present arguments in a jumbled or random order, which can weaken your analysis. Instead, consider building your essay like a compelling case, gradually strengthening your position as you progress. Start with the weaker arguments and then advance to the stronger ones. You could begin by outlining Anselm's initial formulation. Then, you might explore Gaunilo's and Aquinas's objections, demonstrating your understanding of early criticisms. Next, consider how Anselm might respond to these initial objections. The "killer blow" of Kant's critique could then be introduced, providing a powerful challenge to the ontological argument.
Finally, for a more advanced discussion, Plantinga's sophisticated modal logic version of the ontological argument can be brought into the mix. By assessing this modern take on the argument at the end of your essay, you can showcase a deep understanding of the topic's nuances and current debates. By structuring your essay in this way, you not only present a clear and logical progression of ideas but also demonstrate a sophisticated understanding of the ontological argument's complexities and historical development.
