Philosophy · Year 13 · Metaphysics of Mind: Dualism · 3.º Período

Substance Dualism

An examination of Descartes' conceivability and indivisibility arguments for substance dualism. Students will evaluate the conceptual interaction problem and empirical objections.

TL;DR:Substance Dualism, famously associated with René Descartes, posits that the mind and body are two fundamentally different substances: one physical and extended, the other mental and non-extended. Students examine Descartes' indivisibility and conceivability arguments, which rely on the 'clear and distinct' perception of the mind as separate from the body.

• National Curriculum Attainment Targets
• AQA A-Level Philosophy 7172: 3.2.2.1 Substance dualism
• DfE Philosophy AS and A-level subject content: Metaphysics of mind

About This Topic

Substance Dualism, famously associated with René Descartes, posits that the mind and body are two fundamentally different substances: one physical and extended, the other mental and non-extended. Students examine Descartes' indivisibility and conceivability arguments, which rely on the 'clear and distinct' perception of the mind as separate from the body.

This topic is a cornerstone of the Metaphysics of Mind unit in the AQA specification. It forces students to confront the 'interaction problem', how can a non-physical mind move a physical arm? This topic comes alive when students can physically model the interaction (or lack thereof), helping them grasp the profound difficulty of explaining the link between consciousness and the brain.

Key Questions

1. Are the mind and body two distinct substances?
2. Does the conceivability of a disembodied mind prove it is possible?
3. How do the mind and body interact if they are fundamentally different?

Watch Out for These Misconceptions

Common Misconception

Dualism is just the 'soul' from religion.

What to Teach Instead

While related, substance dualism is a formal metaphysical claim based on logical arguments rather than faith. Using 'secular' examples of mental states helps students focus on the philosophical logic.

Common Misconception

Descartes thought the mind was 'inside' the brain like a pilot in a ship.

What to Teach Instead

Descartes actually argued the mind is 'intimately united' with the body, not just a pilot. Peer-led analysis of his 'Sixth Meditation' helps students see the nuance in his position.

Active Learning Ideas

Inquiry Circle

The Indivisibility Test

Students list physical objects and their parts. They then try to 'divide' a thought or a feeling. This hands-on comparison helps them evaluate Descartes' claim that the mind is fundamentally different because it has no parts.

20 min·Small Groups

Role Play

The Ghost in the Machine

One student acts as the 'Mind' (giving commands) and another as the 'Body' (executing them). A third student, the 'Interaction Problem', must try to block the command, forcing the 'Mind' to explain how it can cross the physical barrier.

30 min·Small Groups

Think-Pair-Share

Is a Disembodied Mind Possible?

Students close their eyes and try to 'conceive' of themselves existing without a body. They then discuss with a partner whether 'conceivability' is a reliable guide to 'possibility', as Descartes claimed.

15 min·Pairs

Frequently Asked Questions

What is the 'interaction problem' for dualism?

If the mind is non-physical and the body is physical, they have no common properties. Princess Elisabeth of Bohemia famously asked how something with no surface area or location could possibly 'push' or 'move' a physical object like the pineal gland.

How does the 'indivisibility argument' work?

Descartes argued that all physical things are divisible (you can cut a body in half). However, the mind is indivisible (you cannot have half a thought). Therefore, by Leibniz's Law, the mind and body must be different things.

How can active learning help students understand substance dualism?

Active learning, like the 'Ghost in the Machine' role play, makes the abstract 'interaction problem' a physical reality in the classroom. When students have to 'act out' the gap between mind and body, they quickly grasp why this is such a significant hurdle for dualists.

What is 'Leibniz's Law' in this context?

The Identity of Indiscernibles. It states that if two things are identical, they must share all the same properties. Dualists use this to show that since the mind has properties the body lacks (and vice versa), they cannot be the same thing.