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.

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?

Descartes’ scepticism

Descartes’ scepticism

Descartes’ scepticism

Descartes’ scepticism

Descartes’ scepticism

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

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.

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

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

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?

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:

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

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

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.

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