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Philosophy Week two / day two


What is knowledge and do we have any?

Today’s lecture continued on the question on knowledge.

Radical Scepticism

This is the view that any knowledge is impossible. In the extreme view we could argue that we don’t know if we are not merely a  “Brain-in-a-vat ” and  nothing is real you are a harvested brain being fed experiences.

…. like in the film The Matrix you think everything is real but how do you know?

A brain in a vat with surprisingly good muscle tone for a body that has never moved.

René Descartes

Thus, all Philosophy is like a tree, of which Metaphysics is the root, Physics the trunk, and all the other sciences the branches that grow out of this trunk, which are reduced to three principal, namely, Medicine, Mechanics, and Ethics. By the science of Morals, I understand the highest and most perfect which, presupposing an entire knowledge of the other sciences, is the last degree of wisdom.

Descartes most famously said – thought cannot be separated from me – this is known as cogito ergo sum (English: “I think, therefore I am”). Therefore, Descartes concluded, if he doubted, then something or someone must be doing the doubting, therefore the very fact that he doubted proved his existence. “The simple meaning of the phrase is that if one is sceptical of existence, that is in and of itself proof that he does exist.

He concludes that he can be certain that he exists because he thinks. But in what form? He perceives his body through the use of the senses; however, these have previously been unreliable. So Descartes determines that the only indubitable knowledge is that he is a thinking thing. Thinking is what he does, and his power must come from his essence.

So this idea of how do I know I am not a brain-in-a-vat is not new. Descartes died in 1650.

Epistemic Vertigo

The picture of ‘The Scream’ here is quite apt. It was about how I was feeling at this point. I didn’t as I didn’t think anyone would take any notice of me.

credit buttersafe.com comics.

I know that humans are fallible and that most people don’t know as much as they think they do. I did, however, think that my own existence was one thing I could rely on. If not then childbirth was unnecessarily painful and I would like a different program if I get to play this game again. – See EDCMOOC re weird reference to a game.

What I have I learned?

Some people out there believe everything they are told. They end up betting on an old nag at Cheltenham and finish up in the poor house.

Some people out there believe nothing they are told. They usually end up dead whilst stabbing themselves to see if they are real or locked up somewhere to stop them doing it to to other people.

The rest of us are somewhere in the middle. We believe that we exist and have hands and jumpers.

Philosophy is about questioning things that are important to us. I am going to add that, for me, I don’t think it is necessary to question my existence or that of jumpers.



  1. John Mitchell says:

    Re ” I don’t think it is necessary to question my existence or that of jumpers.” . . . For me the point of Radical Scepticism is that we should not take our quest for ultimate reality too seriously. It reminds me of a poster I saw on a colleague’s wall years ago: ‘The world is not made of atoms and molecules but of stories.’ [She taught Literature; I taught Mathematics] Literature, Science, Mathematics, Religion, History . . . all of them offer us models of reality rather than reality itself. What matters for me is that these models manage to get along with each other and help us to live lives that are satisfying and useful for our fellow-travelers.

    • Louise Taylor says:

      Thank you for your comment John. I like that poster. Yes all these things need to come together for an understanding. I teach English so I can relate more to Literature, History and languages than Science and maths but I know they have their place.

  2. Frank Brown says:

    I see no value in radical skepticism. First, brain-in-a-vat fails Occam’s razor miserably. Second, such questioning does not provide us with any useful insight nor does it instruct us on how to better think about existence, so far as I can see.

    Let’s see, what was that again? Asking the right questions?

    For my part, I don’t really care to argue about this or that philosophical view. I find learning of and considering the view interesting and potentially instructive… but then I move on. Adopt what I like, reject what I don’t. But any meaningful debate disappears when we begin questioning all knowledge in the extreme: how do I know for sure that the 49’ers didn’t win the superbowl?

    • Louise Taylor says:

      Thank you for that Frank. That is a totally new concept for me so I have just spent a happy hour reading about ‘ Occam’s razor’ which made a lot of sense. I like the idea of taking the simplest path.
      I think that radical scepticism holds as much interest for me as extreme ironing.

  3. […] I am‘. The replicants think and therefore they exist but are they human? We also looked at radical scepticism and the question of whether we are real, how do we know that we are not a brain in a jar.  For […]

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