Philosophy · Year 13 · Metaphysics of God: Concept and Existence · 1.º Período

Ontological Arguments

An exploration of a priori arguments for God's existence, focusing on Anselm, Descartes, and Malcolm. Students will evaluate criticisms from Gaunilo and Kant.

TL;DR:Ontological arguments are unique in philosophy because they attempt to prove God's existence a priori, using nothing but the definition of God. This topic focuses on the classic formulations by St Anselm and Descartes, as well as Norman Malcolm's modern modal version. Students must evaluate whether existence can truly be a 'perfection' or a 'predicate' that adds to a concept.

• National Curriculum Attainment Targets
• AQA A-Level Philosophy 7172: 3.2.1.2 Ontological arguments
• DfE Philosophy AS and A-level subject content: Arguments for the existence of God

About This Topic

Ontological arguments are unique in philosophy because they attempt to prove God's existence a priori, using nothing but the definition of God. This topic focuses on the classic formulations by St Anselm and Descartes, as well as Norman Malcolm's modern modal version. Students must evaluate whether existence can truly be a 'perfection' or a 'predicate' that adds to a concept.

The topic is a rigorous exercise in logic and linguistic analysis, aligning with National Curriculum goals of developing precise reasoning skills. It introduces students to the fundamental divide between rationalism and empiricism. Students grasp this concept faster through structured discussion and peer explanation, as the 'leap' from a definition to reality often feels counter-intuitive and requires verbal processing to deconstruct.

Key Questions

1. Can existence be considered a predicate?
2. Does the concept of a greatest conceivable being necessitate its existence?
3. How effective is Gaunilo's perfect island objection?

Watch Out for These Misconceptions

Common Misconception

Anselm is just saying 'God exists because the Bible says so'.

What to Teach Instead

Anselm's argument is purely logical and does not rely on scripture. Peer-teaching the 'reductio ad absurdum' structure helps students see it as a formal logical proof rather than a statement of faith.

Common Misconception

Kant's objection that 'existence is not a predicate' means God doesn't exist.

What to Teach Instead

Kant is only arguing that the ontological argument fails as a proof, not that the conclusion is false. Using hands-on examples of describing a 'hundred thalers' helps students see that adding 'exists' doesn't change the description.

Active Learning Ideas

Role Play

Gaunilo vs. Anselm

One student plays Gaunilo, arguing for the existence of a 'perfect island' using Anselm's logic, while the other plays Anselm trying to explain why the logic only applies to God. This helps students identify the 'special' nature of the concept of God in this argument.

20 min·Pairs

Gallery Walk

Predicate or Not?

Stations around the room list different words (e.g., 'green', 'heavy', 'exists', 'expensive'). Students move in groups to discuss whether each word changes our concept of an object or simply tells us something about its status in the world, mirroring Kant's objection.

30 min·Small Groups

Inquiry Circle

Mapping the Modal Argument

Students work in groups to break down Norman Malcolm's argument into a series of logical steps on a whiteboard. They must identify the exact point where the argument moves from 'logical possibility' to 'necessary existence'.

25 min·Small Groups

Frequently Asked Questions

What is the main difference between Anselm and Descartes?

Anselm focuses on God as 'that than which nothing greater can be conceived' and uses a reductio ad absurdum. Descartes treats God as a 'supremely perfect being' and argues that existence is a necessary part of perfection, much like three sides are a necessary part of a triangle.

Why is Gaunilo's island objection important?

Gaunilo uses a 'parity of reasoning' argument. He shows that if Anselm's logic works for God, it could be used to prove the existence of anything 'perfect', like a perfect island. This forces theists to explain why God is a unique case.

How can active learning help students understand ontological arguments?

Ontological arguments are notoriously slippery. By using role play and collaborative mapping, students are forced to verbalise the logic. This surfaces the 'aha!' moment when they realise the argument is about the definition of existence itself, rather than just a list of God's powers.

What is a 'modal' argument in this context?

Modal logic deals with possibility and necessity. Norman Malcolm's argument is modal because it focuses on the idea that if God's existence is possible, and God is a necessary being, then God must exist. It avoids some of Kant's criticisms by focusing on 'necessary existence' rather than just 'existence'.