Soory, don't know what that has to do with what I posted.
It is exactly the same argument. Penrose/Lucas argue that since humans have access to mathematical truth that cannot be gleemed using any algorithm, our brains must not follow an algorithm.
And it fails in exactly the same way -- we don't have intuitive access to mathematical truth, we have access to what we
think is mathematical truth, and the latter can certainly be gleemed using an algorithm.
But by disagreeing with me are you saying you believe "a brain in a vat" questioning whether it's a brain in a vat might still be only a brain in a vat?
If so... from where does such knowledge of an external reality (outside the vat) originate?
But it isn't knowledge of an external reality, that is what I am telling you. It is knowledge about the reality of the vat ( which is the reality the brain perceives ), combined with some imagination/extrapolation, to form what the brain
thinks an external reality
might be like, were there to be an external reality outside of its own.
Think about it -- you are in a space the shape of a cube with no exits. In the space with you is a dollhouse, except there is no roof on the dollhouse and no ceiling to any of the rooms in it, so you can see inside. There is also a room in the dollhouse with no doors, and a little plastic character that looks like you. We can throw in a mirror as well, so you can see what you look like.
Do you need to have any knowledge of what is outside your space, or whether there even is more to your reality besides your space, to just look at the dollhouse and notice the similarities? A space in the dollhouse, which you immediately notice is a room, has the same shape as the space you are in. There is a representation of a humanoid in that space, which you notice looks sort of like you ( because you know what you look like thanks to the mirror we provided ). No -- you don't need any knowledge of what is outside, you can simply look at what you have in front of you and extrapolate.
Furthermore, any conjectures you make have no relationship with what is actually outside your space. Zero. Because you have no access to what is outside your space. If one of your conjectures happens to match what is outside your space, that is just luck, and you don't even have a way to confirm it, because you have no access to what is outside your space.