DOSSIER 4 · THE ONTOLOGICAL ARGUMENT

Section 1 of the Apologia Studio: The Arguments for the Existence of God.

(a) THE ARGUMENT IN ITS STRONGEST FORM

Every other dossier in this section reasons from something outside God — morality, the cosmos, design, the mind. The ontological argument attempts something far more audacious: to reason from the idea of God alone to His existence. It is the only argument in the set that needs no telescope, no laboratory, and no history book — only the concept itself.

Anselm's original (1078)

Anselm of Canterbury, a monk writing a prayer, defined God as "a being than which nothing greater can be conceived" (Proslogion, ch. 2) and then argued by reductio:

1. God — a being than which nothing greater can be conceived — exists at least in the understanding (even the fool of Psalm 14:1 understands the phrase when he hears it).
2. To exist in reality as well as in the understanding is greater than to exist in the understanding alone.
3. If that-than-which-nothing-greater-can-be-conceived existed in the understanding only, then we could conceive of a greater being — the same being, existing also in reality. That is a contradiction.
4. Therefore, a being than which nothing greater can be conceived exists in reality as well as in the understanding.

In chapter 3 Anselm added the argument's deeper half: a being that cannot be conceived not to exist is greater than one that can be conceived not to exist — so God exists not contingently, as a happy accident, but necessarily: if He exists at all, His non-existence is inconceivable.

Plantinga's modal form

Alvin Plantinga revived the argument in the 20th century using modal logic — the logic of possible worlds (God, Freedom, and Evil, 1974; The Nature of Necessity, 1974). His terms: a being is maximally excellent in a world if it is omnipotent, omniscient, and wholly good there; maximally great if it is maximally excellent in every possible world. The argument:

1. It is possible that a maximally great being exists.
2. If it is possible that a maximally great being exists, then a maximally great being exists in some possible world.
3. If a maximally great being exists in some possible world, then it exists in every possible world.
4. If a maximally great being exists in every possible world, then it exists in the actual world.
5. Therefore, a maximally great being exists in the actual world.
6. Therefore, God exists.

The logic, granted the machinery, is valid: everything turns on premise 1 — the possibility premise. If a maximally great being is genuinely possible, then (because such a being, if it exists anywhere, exists necessarily and therefore everywhere) it exists here.

(b) WHAT IT PROVES — AND WHAT IT DOES NOT

Handled carefully, the ontological argument establishes a conditional of enormous importance: God is not the kind of being who might simply happen to exist or happen not to. There is no possible world in which God exists "by luck," and none in which He is a borderline case. Either He exists necessarily, or He is impossible — the middle ground, a merely probable God, is what the argument rules out. That alone transforms apologetics: the question of God is never a coin-flip about one being among billions, but a question about the necessary structure of reality itself. Exodus 3:14 is this dossier's theological root: the God who names Himself I AM THAT I AM is not describing one attribute among others but His very mode of being — self-existent, underived, necessary.

What the argument does not do: it does not, by its possibility premise alone, compel a skeptic's assent — and its own greatest defenders admit this. Plantinga himself concluded that the argument is not a "successful piece of natural theology" in the sense of a proof that any rational person must accept on pain of irrationality, because premise 1, while he holds it rational to accept, can be rationally doubted by someone who instead accepts the possibility that no maximally great being exists. Honesty about this is part of the dossier.

(c) THE OBJECTIONS AT FULL STRENGTH

1. Gaunilo's perfect island (1078 — the argument's first critic, a fellow monk). By Anselm's logic, Gaunilo argued, I can define a perfect island — an island than which no greater island can be conceived — and prove it exists the same way: it would be greater if it existed in reality. Since that is absurd, the logic must be broken somewhere.

2. Aquinas's refusal. Thomas Aquinas, no enemy of natural theology (he gave the Church the Five Ways), rejected the ontological argument outright (Summa Theologiae I, q. 2, a. 1): God's existence is self-evident in itself — since God's essence is His existence — but it is not self-evident to us, because we do not know God's essence. From the fact that we can form and understand a concept of God, His existence does not follow for minds like ours; it must be demonstrated from His effects. On Aquinas's account, Anselm's argument moves inside the understanding and never legitimately steps outside it.

3. Kant: existence is not a predicate. Immanuel Kant's Critique of Pure Reason (1781) delivered the objection that dominated the next two centuries. "Being," Kant argued, "is obviously not a real predicate" — existence adds nothing to a concept's content. A hundred real thalers contain not one coin more than a hundred merely possible thalers; the concept is identical whether the thing exists or not. Therefore no analysis of any concept — even the concept of a most perfect being — can conjure existence out of it. To exist is for a concept to be instantiated, and that must be established from outside the concept, never unpacked from within it.

4. The symmetry problem (against Plantinga's form). If the defender may assert "it is possible that a maximally great being exists," the atheist may with equal right assert "it is possible that no maximally great being exists" — and from that premise, by the same modal machinery run in reverse, it follows that no maximally great being exists in any world, including ours. Two contradictory "possibilities," both apparently assertable, cannot both be true. The argument seems to assume the very point in dispute: which possibility is genuine.

(d) THE ANSWERS

To Gaunilo: the parody misfires on a technical point that matters. Islands, by their nature, have no intrinsic maximum of excellence — for any island, a greater (one more palm tree, one more lagoon) is always conceivable; the concept "greatest conceivable island" is therefore incoherent, like "the largest number." God, on Anselm's definition, is not like that: omniscience, omnipotence, and perfect goodness do have intrinsic maxima (knowledge of all truths, power over all possibles). The parody works only against greatness-concepts with no built-in ceiling, and the God-concept is precisely the one that has one. Gaunilo's objection remains valuable — it teaches the student exactly where the argument's joints are — but it does not break it.

To Aquinas: the defender concedes most of the point and should say so. Aquinas's distinction is a permanent caution: this argument convinces only those who can be brought to see that the God-concept is the concept of a being whose essence involves existence. That is why the Studio places this dossier fourth and not first: it is a summit argument, powerful for the student who has walked the other roads — the moral, cosmological, and design arguments give the content that lets a man see what "that than which nothing greater can be conceived" actually contains. Aquinas's own Five Ways then appear not as rivals but as the ascent by which most minds must climb.

To Kant: two replies stand. First, Plantinga's modal form is partly built to absorb Kant: it does not treat existence as one more property sprinkled onto a concept (like redness); it treats necessary existence and existence-in-every-world as the modal status of the being, and necessity arguably is a genuine great-making feature — a being that cannot fail to exist is greater than one that can, and Kant's thalers example simply does not address a being defined by necessary existence, since Kant's coins are contingent objects. Second, however, the honest defender concedes Kant's deeper caution: showing that existence belongs to God's concept does not by itself exhibit God to a man who doubts whether the concept is instantiated — which is why premise 1 of the modal argument remains the contested ground.

To the symmetry problem: Plantinga's own candour is the answer, and the Studio repeats it without flinching: both possibility-claims cannot be true, and the argument by itself does not adjudicate between them — what it shows is that belief in God, if the possibility premise is accepted, is not a gamble but a logical consequence, and that unbelief must correspondingly commit to the strong claim that a maximally great being is impossible. That reframing is itself a victory of a kind: it forces the debate off "you can't prove God" and onto "is God possible?" — and the other five dossiers are the Studio's case that He is far more than possible. The ontological argument functions in the cumulative case as the keystone shape, not the arch.

(e) WHERE IT WAS FOUGHT

Uniquely in this section, this argument's great encounters are in print rather than on a debate stage: Anselm vs. Gaunilo (1078 — Gaunilo's On Behalf of the Fool was bound into manuscripts of the Proslogion itself, with Anselm's reply appended), Aquinas's refusal in the Summa, Kant's thalers in the Critique, and Plantinga's revival in God, Freedom, and Evil (1974). In modern debate the modal argument appears as one exhibit among Craig's cumulative case rather than a headline bout; students looking for its live treatment should begin with Plantinga's own lectures and the Proslogion read whole — it is a prayer of eleven short chapters, and it repays being read as one. Where the Earnest Contention canon treats the neighbouring ground — the rational coherence of the God-concept — is in Lennox vs. Dawkins — has science buried God?, where the intelligibility of the universe does ontological work in public dress.

(f) SCRIPTURE ANCHORS (KJV)

"And God said unto Moses, I AM THAT I AM: and he said, Thus shalt thou say unto the children of Israel, I AM hath sent me unto you." — Exodus 3:14

The self-existent God of the burning bush is the necessary Being of this dossier, named and speaking.

"The fool hath said in his heart, There is no God." — Psalm 14:1

Anselm framed the entire Proslogion as an answer to this verse's fool: the argument begins from the one proposition the fool himself understands.

(g) GO DEEPER

• Anselm, Proslogion (1078), chs. 2–4, with Gaunilo's On Behalf of the Fool and Anselm's Reply — the whole controversy in a single short sitting; read it in that order.
• Alvin Plantinga, God, Freedom, and Evil (Eerdmans, 1974), Part I — the modal argument by its author, including his own honest verdict on what it does and does not accomplish.
• Thomas Aquinas, Summa Theologiae I, q. 2 — the refusal (a. 1) and the Five Ways (a. 3) together: the classic map of where this argument stands in the house of natural theology.
• Immanuel Kant, Critique of Pure Reason (1781), the "Ideal of Pure Reason" — the thalers; meet the strongest critic in his own words.

THE HONEST NOTE ON ITS STANDING — required reading in this dossier. Of the six arguments in this section, this is the one on which the defenders themselves are most divided: Aquinas rejected it, Kant is widely (though not universally) taken to have refuted its classical form, and its greatest modern champion, Plantinga, presents the modal version as establishing the rational acceptability of theistic belief rather than a knock-down proof. The Studio teaches it because it is historically indispensable, because its modal form is genuinely formidable, and because its central insight — God, if He exists at all, exists necessarily — is pure biblical doctrine (Exodus 3:14). But no student of this Studio rests the case for God on this dossier alone, and any who presents it as an unanswerable syllogism has not read its own section (d). We contend earnestly; we also contend honestly.