1. On your whiteboards:
3 differences between philosophical scepticism and everyday incredulity
What is meant by “infinite regress”? Why is it a problem for the epistemological sceptic?
What is foundationalism?
Today’s Objective:
To understand Descartes’ Three Waves of Doubt and the responses to them.

2. Reading Task Descartes’ first meditation
How was it?
What was difficult? If I gave you another reading to do now, would you approach it any differently?
Go through your annotations and compare with your friend. Do you agree about what Descartes is saying?

3. Descartes’ scepticism

4. Descartes’ scepticism

5. Descartes’ scepticism

6. Descartes’ scepticism

7. Descartes’ scepticism

8. Descartes’ scepticism
Can Descartes really doubt ALL of his beliefs?

9. Evaluating Descartes’ method of doubt
If he doubts all his beliefs, he must doubt his belief that he had some beliefs. But if he doubts that he had beliefs, then he can’t doubt those beliefs. So, there seem to be limits to how sceptical he can be, and Descartes must retain the basic framework of beliefs concerning the nature of doubt, certainty an evidence which allow his method to operate.

10. Wave 1 The argument from illusion
We have covered this thoroughly in our study of Direct Realism.
Is Descartes right to doubt his senses?

11. Wave 2 The argument from dreaming Matrix clip 1 Problems:
Dreams can be distinguished from waking life
Dreams must come from waking life

12. I’m walking along Skegness beach in the sunshine
Wave 3
The Matrix is a modern version of the old “brain-in-a-vat” thought experiment
The evil demon
Matrix 2
Matrix 3
I’m walking along Skegness beach in the sunshine
Do you know you are not in the Matrix right now?
If we are in the Matrix, is there anything we can be certain of?

13. You should now be able to explain:
Descartes’ method of doubt
How each wave of doubt works
How effective is each wave for Descartes’ argument?
And to argue:

14. Responses to scepticism 1 – Descartes’ own response
The cogito  Clear and distinct ideas
Clear and distinct doesn’t mean it’s true
How do we know which ideas are clear and distinct?
Needs to prove God to dispel all doubt
Cartesian circle

15. Responses to scepticism 2 - Empiricism
Think back to Russell, Locke and Berkeley. How would they persuade Descartes to trust his senses?

16. Responses to scepticism 3 - Reliabilism
Scepticism tries to show we have no justification for knowledge, so one of the necessary conditions is missing, so we don’t have knowledge.
But reliabilism denies that we need justification for knowledge. We just need our knowledge to be arrived at via a reliable process.
I can know that I am not a brain in a vat as long as the beliefs I have about the reality of objects around me are produced by a reliable process.
I don’t have to know what this reliable process is, or whether I am in a vat or not. I can still have knowledge.

17. You should now be able to explain:
Three responses to Descartes’ scepticism
How sceptical should we be?
And to argue: