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Course 14 · Lesson 2.2

Gaunilo and the perfect island objection

10 minute read

Lessons in this course

Course 14 outline

Module 1: Arguments, Existence and Necessity

  1. What natural theology attempts and what it does not
  2. Necessary and contingent existence
  3. How to read and test an argument for God
  4. Philosophy of religion today: a map of the field

Module 2: The Ontological Argument

  1. Anselm and the argument of the Proslogion
  2. Gaunilo and the perfect island objection
  3. Kant: existence is not a real predicate
  4. What the ontological argument would show if it worked

Module 3: Cosmological Arguments

  1. Aquinas: the first three ways
  2. Infinite regress: what is the problem?
  3. Leibniz, the principle of sufficient reason and the argument from contingency
  4. Objections: the brute fact reply and the fallacy of composition

Module 4: The Kalam Cosmological Argument

  1. The kalam tradition: Philoponus, al-Ghazali and Bonaventure
  2. The modern argument: whatever begins to exist has a cause
  3. Did the universe begin? Philosophy and cosmology
  4. Objections and replies, and what follows about the cause

Module 5: Teleological and Fine-Tuning Arguments

  1. From Aquinas’s fifth way to Paley’s watch
  2. Hume and the Dialogues Concerning Natural Religion
  3. Darwin and the change in the design argument
  4. The fine-tuning argument: what is claimed and what is debated
  5. The multiverse and other replies

Module 6: The Moral Argument and Divine Hiddenness

  1. The moral argument: Kant, Lewis and contemporary forms
  2. The Euthyphro question and moral realism without God
  3. Evolution and moral knowledge
  4. The argument from divine hiddenness and Christian replies

Module 7: Contemporary Modal Arguments and Evaluation

  1. Possible worlds and modal logic in plain language
  2. Plantinga’s modal ontological argument
  3. Assessing the modal argument: what it needs and what it shows
  4. Weighing the arguments together, and what none of them prove

All courses

Program / Course 14: Arguments for the Existence of God / Lesson 2.2

What you will learn

  • State Gaunilo’s objection and the parody argument about the lost island.
  • Explain Anselm’s reply that the argument applies only to a being than which nothing greater can be thought.
  • Explain why a parody argument is a useful test of an argument’s form.
  • Weigh whether the reply to the island objection succeeds.

The big idea

Gaunilo, a monk of Marmoutier and a contemporary of Anselm, replied to the Proslogion on behalf of the fool. He argued that Anselm’s reasoning, if valid, could prove the existence of a perfect lost island, which is absurd. Anselm answered that the argument applies only to a being than which nothing greater can be thought, and that islands, which can always be improved, do not qualify. Philosophers still debate whether this reply is enough.

Key terms

Parody argument
An argument with the same form as another but with a different subject, offered to show that the original reasoning proves too much.
Reductio of an argument form
Showing that a type of reasoning is unreliable because it can be used to reach a false or absurd conclusion.
Maximal greatness
Being as great as it is possible to be in every respect that makes a being great.
Intrinsic maximum
A highest point on a scale that has a natural limit, as opposed to a quantity that can always be increased.
Greater-making property
A feature that makes a thing better or greater, such as knowledge or goodness, in contrast to a feature that is simply neutral.
Proportion
In this lesson, the relation between how far an argument’s form is general and how far its subject is special.

Background

Gaunilo’s reply is titled On Behalf of the Fool. It survives because Anselm thought it worthy of an answer and had it copied along with his own response. Gaunilo was a believer, so his purpose was not to deny God but to test the argument. He thought that the argument as stated did not compel assent.

He makes two main points. First, he doubts that anyone can truly have in mind a being than which nothing greater can be thought, since the idea of such a being is formed only through words and by comparison to things already known. Second, he offers an example. Suppose someone said that somewhere in the ocean there is an island more excellent than all other lands, and that because it is more excellent to exist than not to exist, the island must exist. Listeners would think the person was joking, Gaunilo says, until he showed how the island’s existence could be proved.

Anselm’s reply, in the Responsio, is that if Gaunilo can find something other than God that fits the description, he will provide the lost island itself. He holds that the argument applies uniquely to the greatest conceivable being.

Step-by-step explanation

Step 1: The parody in numbered form

1. The perfect island is an island than which no greater island can be thought. 2. It exists in the understanding. 3. An island that exists in reality is greater than one that exists only in the understanding. 4. If the perfect island existed only in the understanding, a greater island could be thought. 5. This is a contradiction. 6. So the perfect island exists in reality.

Gaunilo’s point is that this reasoning has the same form as Anselm’s, but the conclusion is plainly absurd. If the form of the argument can prove a perfect island, it cannot be trusted to prove God.

Step 2: Anselm’s reply

Anselm answers that his argument works only for that than which nothing greater can be thought, and an island is not such a thing. An island is the kind of thing that can always be made better, by more fruit, more beauty or more size. There is no greatest island. By contrast, a being that is greatest in every respect has a natural upper limit.

The reply is that the argument depends on a special kind of subject, one with an intrinsic maximum. A parody must therefore show that something else has the same special character.

Step 3: Does the reply succeed?

Many philosophers think the reply is strong. Plantinga argued that the notion of a maximally great island is incoherent, since islands have no maximum, and that the notion of a maximally great being is not obviously so. Others are less convinced. They say that parallel parodies can be built with other limit concepts, such as a perfect devil, a being than which nothing worse can be thought. If the same argument form gives that, then the form is suspect.

Defenders answer that evil is a lack of goodness, so there cannot be a maximally evil being, as it would lack the existence and power needed. Critics reply that this relies on a controversial theory about evil.

Step 4: What a parody can and cannot do

A good parody does not refute an argument by itself. It places a burden on the defender: to explain what differs between the original and the parody. If the defender can name a relevant difference, the argument survives. If not, the argument form is in doubt. This is a general method that you can apply to other arguments in the course.

Step 5: Gaunilo’s first point

Gaunilo’s doubt that a person can have the idea of a greatest conceivable being is separate from the island, and it is often overlooked. If the idea cannot be properly formed, the argument fails at the second step. Anselm replies that the fool does understand the phrase, since otherwise he could not deny it. Philosophers have debated this too.

  1. What is the same in the island argument and Anselm’s argument, and what differs?
  2. Is there such a thing as a greatest possible island? Why or why not?
  3. What would a parody of Anselm’s argument need to show to succeed?
  4. Does a perfect devil argument seem more or less convincing than the island?
  5. Why might Gaunilo have been loyal to the Christian faith and still object?
  6. Is it fair to say an argument fails because a parody exists?

Examples

The lost island

Gaunilo imagined an island lost somewhere in the ocean, richer and more beautiful than any known, and asked what would persuade a reader that it exists merely because it is defined as the best conceivable island. The example is meant to be humorous and also pointed.

No greatest number

No matter how large a number is named, a larger one can be named by adding one. So the largest number is not a coherent idea. Plantinga used this kind of comparison to say that the greatest island is likewise incoherent, since islands can always be improved.

The perfect devil

Some critics suggested a being than which nothing worse can be thought, and then argued in the same form that it must exist. Defenders respond that the notion is not coherent, because badness is a defect and a being with the greatest defects could not exist at all. Critics reply that this reply assumes a specific view of evil.

Different perspectives

Catholic

Catholic philosophers divide. Some accept Anselm’s reply and treat the argument as defensible. Many Thomists, following Aquinas, regard the argument as flawed for a deeper reason: it treats a thought about God as if it settled whether God exists. For them Gaunilo’s objection reveals a symptom of the flaw.

Orthodox

Orthodox thinkers rarely discuss the island itself. Their typical concern is that to define God as the greatest conceivable thing treats God as an item in a ranking, whereas the tradition holds that God lies beyond every ranking.

Protestant

Plantinga, a Reformed philosopher, defended the reply that an island has no intrinsic maximum. Other Protestant philosophers regard the parody as unanswered. Barth thought that the argument cannot be assessed by outsiders and so the parody misses its point.

Scholarly views

Historians note that Gaunilo wrote respectfully and that Anselm prized the objection. They also note that Anselm’s reply is brief and that its interpretation is disputed. The parody method became standard in later philosophy.

Skeptical views

Skeptics treat the island as the simplest sign that the argument proves too much. They add that even if some limit concepts resist parody, the argument rests on the claim that existence is a mark of greatness, which is the point at issue.

Why it matters

The parody method is one of the most useful tools in philosophy. It teaches a reader to ask whether an argument’s form is reliable and not only whether its subject is attractive. It also shows how a respectful critic, himself a believer, can strengthen an argument by testing it.

Common misunderstandings

Misunderstanding: Gaunilo was an atheist.

Correction: Gaunilo was a monk and accepted that God exists. He objected only to the argument.

Misunderstanding: The island objection has refuted the ontological argument.

Correction: Anselm and many later philosophers hold that it does not, since islands lack an intrinsic maximum. Others find the reply inadequate. The matter is disputed.

Misunderstanding: Anselm ignored the objection.

Correction: He answered it carefully and had it published with his own work.

Misunderstanding: Any parody of an argument disproves it.

Correction: A parody is only effective when it truly shares the relevant features of the original. Showing that it does not is a legitimate reply.

Knowledge check

What was Gaunilo’s parody argument?

He argued that someone could define a perfect island as one than which no greater can be thought, and then reason, in Anselm’s form, that because existing is greater than not existing, the island must exist. Since this is absurd, he concluded that the form of the argument does not reliably establish existence, and so cannot be trusted to prove God.

How did Anselm reply?

He said that the argument applies only to that than which nothing greater can be thought, and an island is not such a thing, since islands can always be improved. There is a natural limit to greatness for a being but not for an island. He offered to give Gaunilo the island if he could find anything else that fits the description.

What is the perfect devil parody, and what is the usual reply?

It reasons from a being than which nothing worse can be thought and concludes that it exists. Defenders reply that evil is a lack of goodness, so a being wholly bad could not exist. Critics answer that this relies on a particular theory of evil that the argument has no right to assume.

What is the value of a parody argument?

A parody tests whether an argument’s form is reliable. It does not by itself refute the original, but it requires the defender to name a relevant difference. If a difference exists, the original survives. If none can be named, the form is in doubt. The method applies to many arguments.

Think it through

  1. Is there anything else besides God that you think has an intrinsic maximum?
  2. What does it say about an argument that it can be parodied?
  3. How would you answer the perfect devil objection?
  4. Why might a believer welcome serious objections to arguments for belief?

Independent assignment

Build and test a parody

In your own notebook, write 300 to 450 words. Write Gaunilo’s island argument in numbered steps beside Anselm’s. Then write a paragraph naming one difference between the two that you think matters, and one reason a critic might say it does not. Finish by saying whether the difference rescues Anselm’s argument in your judgment. Do not send this to anyone.

Further study