Philosophical Scepticism: Does the Evil Demon Mean Knowledge is Impossible? (Epistemology Episode 4)

An overview of philosophical scepticism and whether thought experiments such as Descartes' evil demon, brain in a vat, and the simulation hypothesis mean it is impossible to know anything.

The global sceptic argues that because we can't justify whether we are in some sceptical scenario where all our beliefs are false or not, then we can't justify any of our beliefs and so can't claim to know anything. For example, the global sceptic would argue you don't know "I have hands" because you can't justify the claim that you're not a brain in a vat with no hands. However, the non-sceptic rejects the sceptic's claim and defends our ordinary knowledge. For example, the non-sceptic would say you can know "I have hands".

This video outlines various versions of the sceptical hypothesis - including brain in a vat, the Matrix, the simulation hypothesis, and Descartes' evil demon - and the role these thought experiments play in epistemology. We then adapt arguments from previous videos to serve as responses to global scepticism, including Descartes' foundationalism, Russell's argument that mind-independent objects are the best hypothesis to explain perceptions, Berkeley's idealist theory of perception, and externalist definitions of knowledge (in this case reliabilism).

These videos are based around the AQA A-level philosophy syllabus. This video in particular is heavily focused on the responses listed on this syllabus, which perhaps aren't the strongest or most popular arguments in contemporary academic epistemology. Perhaps I will do a part 2 of this topic covering some further responses but for now I have included some further reading below.

00:00 Intro
01:39 The role of philosophical doubt in epistemology and examples of sceptical hypotheses that undermine our ordinary justifications
07:42 Descartes' 3 waves of doubt (illusion, dreaming, evil demon)
13:07 Responses to global scepticism
13:59 Descartes' response to scepticism (foundationalism/intuition and deduction)
22:07 Empiricist/indirect realist-style responses (inc. Russell's argument that the external world is the best hypothesis)
26:43 Berkeley's idealism as a response
30:14 The reliabilism definition of knowledge as a response (i.e. epistemic externalism)
37:19 Summary: global scepticism and responses
40:41 Outro and sales pitch for Descartes' Meditations

References/further reading:
My website: https://philosophyalevel.com/aqa-phil...
My book: https://www.amazon.com/How-Get-Level-...
Meditations on First Philosophy by Rene Descartes. Full text here: https://philosophyalevel.com/rene-des...
My definitions of knowledge video for reliabilism:    • What is Knowledge? Beyond Justified T...  
My knowledge from perception video for Russell and Locke's indirect realist responses, and Berkeley's idealism as a response:    • Knowledge from Perception: Direct Rea...  
Some stuff I wrote about Nozick's definition of knowledge, which can also be used to respond to scepticism: https://philosophyalevel.com/posts/no...
Stanford's summary of scepticism: https://plato.stanford.edu/entries/sk... (note this probably won't be particularly helpful for A-level philosophy students, for reasons mentioned above, but if you're an undergraduate or whatever writing a paper on scepticism this is probably a good place to start)
Internet Encyclopedia of Philosophy summary of scepticism: https://iep.utm.edu/skepcont/ (this page is good, basically a less wordy version of the Stanford page but again not particularly relevant for A-level students unless you want to do a bunch of extra reading on stuff you'll never get asked questions on)
Wikipedia page on epistemic externalism: https://en.wikipedia.org/wiki/Interna... (this is how the reliabilist definition of knowledge works as a response to scepticism)
Stanford's page on coherentism: https://plato.stanford.edu/entries/ju... (this is a response I didn't cover in this video, but is a way one can argue that our beliefs are justified without having to trace our justifications back to the foundations of certainty as Descartes attempts to do)
A Defence of Common Sense by G.E. Moore: http://www.sophia-project.org/uploads... (Moore's response kind of flips the sceptical argument round the other way: Where scepticism is used to disprove "I know I have hands", Moore uses "I know I have hands" to disprove scepticism)
Proof of an External World by G.E. Moore: https://gwern.net/doc/philosophy/epis...

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