Brain in a Vat – What is Reality

Apr 30, 2011 by

After watching the Films “The Matrix “ and “Vanilla Sky” I have been fascinated by the concepts and ideas they addressed. In both films the individuals are unaware that they are experiencing everything only in their minds. All reality and their day to day life experiences are illusionary. So how do we know what reality is? . As in “The Matrix”, how do we know that our brains are not wired to a clever simulation program reproducing everything from worms in the ground to feeling the pavement beneath our feet ?

These films are in fact based on intriguing and long debated philosophical questions : What is Reality & What is Knowledge ?



he Brain in a Vat

‘Imagine that a human being has been subjected to an operation by an evil scientist. The person’s brain has been removed from the body and placed in a vat of nutrients which keeps the brain alive. The nerve endings have been connected to a super-scientific computer which causes the person to have the illusion that everything is perfectly normal. There seem to be people, objects, the sky, etc.; but really all the person is experiencing is the result of electronic impulses travelling from the computer to the nerve endings.’

A nightmare scenario, the stuff of science-fiction? Perhaps, but of course that’s exactly what you would say if you were a brain in a vat! Your brain may be in a vat rather than a skull, but your every experience is exactly as it would have been if you were living as a real body in a real world. The world around you, your chair; the mouse in your hands, your hands themselves — are all part of the illusion, thoughts and sensations feed your disembodied brain by the scientist’s super-powerful computer.


Vat Origins

The modern re-telling of the brain-in-a-vat story was given by the American philosopher Hilary Putnam in 1981 but it is essentially an updated version of the 17th-century horror story “the evil demon” (maim genie) conjured up by the French philosopher René Descartes in 1641.

“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 alt external things are merely the delusions of dreams which he has devised to ensnare my judgment.”

We think we know lots of things, but can we ever be sure we’re not hallucinating or dreaming, or that our memory isn’t playing tricks? If the experience of dreaming is indistinguishable from our waking experience, we can never be certain that something we think to be the reality is in fact the reality. Such concerns, taken to an extreme, lead to evil demons and brains in vats.

You probably don’t believe you are a brain floating in a vat, Most philosophers probably don’t believe they’re brains in vats. But you don’t have to believe it, you only have to admit you can’t be certain that you’re not. The problem is that, if you do happen to be a brain in a vat (and you just can’t rule out the possibility), all the things you think you know about the world will be false. And if that’s possible you don’t really know anything at all. The mere possibility appears to undermine our claims to knowledge about the external world.
So is there any escape from the vat ?


Escaping the Vat

Descartes thought there was. His aim was to deconstruct everything we think we know & re-build it from the ground up by adopting his ‘method of doubt’. He discarded any beliefs susceptible to the slightest degree of uncertainty. He espied a single speck of certainty – the cogito – on the (apparently) sure foundation of which he begins his task of reconstruction. This led to the now famous and oft quoted conclusion …

Cogito ergo sum – I think therefore I am

Hilary Putnam thinks he too can see a way out and argues that a brain-in-a-vat could not in fact express the thought this it was a brain-in-a-vat, ie that state of being an envatted brain is invisible and indescribable from within.


Conclusion ?

However many subsequent philosophers feel that he has been no more successful than Descartes in vanquishing scepticism. The concern that in the end there is no sure escape from the vat continues to linger on in philosophy.