PHILOSOPHY: Are we brain's in a vat?

How can you be sure you’re not dreaming, right now?  If the experience of dreaming is indistinguishable from that of wakening, how do you know where the dream ends and reality begins?

We think we know lots of things but how can we defend such claims, what grounds can we produce to justify any particular clame to knowledge?  Our supposed knowledge of the world is biased entirely on our perceptions of the world, garnered via our senses, normally with our sense of reason mediating.

But are not such perceptions open to error?

Is it possible to ever be sure that we are not hallucinating or dreaming or that our memory isn’t playing a trick on us?

These are augments that are as old as philosophy itself, but in there modern guise they can be traced back to the 17^th century Descartes who, in his 1641 book: meditations on first philosopher, aimed to reconstruct the entire edifice of human knowledge on unshakable foundations, for which he adopted what he called a ‘method of doubt’  whereby he discarded any beliefs susceptible to the slightest degree of uncertainty.  After pointing out the unreliability of our senses and the confusion created by dreams Descartes pushed his method of doubt to the limit:

“I shall suppose… that some malicious demon of the utmost power and cunning has employed all his energies in order to deceive me.  I shall think that the sky, the air, the earth, colours, shapes sounds and all external things are merely the delusions of dreams which he has devised to ensnare my judgment”

This idea was brought up to date by the modern philosopher Hilary Putnam in his 1981 book asked us to imagine ourselves as a brain in a vat, placed there by some evil scientist, the nerve endings having been connected to a highly advanced computer which cases the brain to believe that everything is perfectly normal.  If this living nightmare sounds like the stuff of science fiction  think on this for a moment, isn’t that exactly what an envated brain would think?  Your brain may well be in a vat rather than a skull, but your every  experience is exactly as it would have been in a real body in the real world. So the world all around you, your body, the screen your reading this on, even me writing this article for you to read are all part of the illusion.

Probably you don’t believe that you’re a brain in a vat, most philosophers don’t believe that they are brains in vats but that’s the rub; you don’t have to believe it you just have to believe that it is possible no matter how unlikely. And if it is possible you don’t really know anything at all, since all your knowledge would have derived from a computer simulation of reality and not from the real world. 

Descartes and Putman, although both playing devil’s advocate many philosophers have been impressed by their skill in setting the sceptical trap than by their subsequent attempts to extricate themselves from it. 

And *THAT* is why The Matrix is one of the best film's of the 1990’s.  But neither science nor philosophy can tell us why the sequels sucked so much