Philosophy · Year 12 · Epistemology: The Limits of Knowledge · 2.º Período

Descartes' Method of Doubt

Students analyse Descartes' three waves of doubt, including the evil demon hypothesis. They will evaluate the cogito as a foundational truth.

TL;DR:Descartes' Method of Doubt is a pivotal moment in the Year 12 curriculum, where students follow the 'father of modern philosophy' in his quest for certainty. The topic covers the three waves of doubt: the argument from unreliable senses, the dreaming argument, and the evil demon hypothesis. Students must understand how each wave is more 'radical' than the last, eventually stripping away all beliefs.

• National Curriculum Attainment Targets
• AQA 7172: Epistemology 3.1.4.2

About This Topic

Descartes' Method of Doubt is a pivotal moment in the Year 12 curriculum, where students follow the 'father of modern philosophy' in his quest for certainty. The topic covers the three waves of doubt: the argument from unreliable senses, the dreaming argument, and the evil demon hypothesis. Students must understand how each wave is more 'radical' than the last, eventually stripping away all beliefs.

The climax of this topic is the 'Cogito' (I think, therefore I am), which Descartes claims is the foundational truth that survives even the evil demon. Students evaluate whether this is a logical deduction or a direct intuition. This topic benefits from hands-on, student-centered approaches where students 'reconstruct' Descartes' journey to see if they reach the same conclusion.

Key Questions

1. What are Descartes' three waves of doubt?
2. Is the 'cogito' immune to the evil demon hypothesis?
3. Does Descartes successfully defeat global scepticism?

Watch Out for These Misconceptions

Common Misconception

Students often think Descartes actually believed there was an Evil Demon.

What to Teach Instead

The demon is a 'thought experiment' or a 'methodological' tool. Active learning simulations help students see that Descartes uses the demon as a way to test his beliefs to the absolute limit, not as a literal claim about reality.

Common Misconception

Students think the Cogito proves that Descartes has a body.

What to Teach Instead

At the point of the Cogito, Descartes has only proven he is a 'thinking thing'. Peer-led mapping of the Meditations helps students see that the body and the world are only 're-proven' much later in his work.

Active Learning Ideas

Inquiry Circle

The Three Waves

Groups are assigned one of the three waves. They must create a 'filter' that shows what types of knowledge that wave 'traps' (e.g., the dreaming argument traps all sensory knowledge but leaves maths intact).

30 min·Small Groups

Mock Trial

Descartes vs The Evil Demon

One student plays Descartes, defending the Cogito. Another plays the Evil Demon, trying to show that even 'I think' could be a deception. The rest of the class acts as the jury to decide if the Cogito is truly certain.

40 min·Whole Class

Think-Pair-Share

Is the Cogito a Proof?

Students discuss whether 'I think, therefore I am' is a logical argument with a missing premise or a single 'flash' of intuition. They share their reasoning with another pair.

15 min·Pairs

Frequently Asked Questions

What are Descartes' three waves of doubt?

1. The Senses: They sometimes deceive us (e.g., illusions). 2. Dreaming: We can't be sure we aren't dreaming right now. 3. The Evil Demon: A powerful being could be deceiving us about everything, even logic and maths.

Why is the Cogito considered 'foundational'?

It is foundational because it is impossible to doubt. Even if you are being deceived, you must exist in order to be deceived. It provides the first 'certain' building block upon which Descartes tries to rebuild all other knowledge.

What are the best hands-on strategies for teaching the Method of Doubt?

Visual mapping is excellent. Have students draw a 'house of knowledge' and then physically 'demolish' different rooms using the three waves of doubt. This physical representation of the 'destruction' of belief helps them understand why Descartes felt he had to start from scratch.

Does the Cogito work if you aren't thinking?

Descartes argues that 'I am, I exist' is true *whenever* it is conceived by the mind. If you were to truly stop all mental activity, you wouldn't be able to affirm your existence, but you also wouldn't be 'you' in the philosophical sense he is discussing.