Descartes and the Demon Possibility

Rene’ Descartes, (31 March 1596 – 11 February 1650) was a French philosopher, mathematician, physicist, and writer who spent most of his adult life in the Dutch Republic. He has been considered the "Father of Modern Philosophy".

What I really found interesting about Descartes is his doubt of his very own existence. I’ll just outline his ideas and theories which I found simply; unique and genius.

Descartes introduced his book of Meditations in 1641 where he revealed his doubts about his existence.

Firstly, he presents his idea of the “Brain in Vat”. Here Descartes states the possibility that what is there is a genius demon that has disconnected the human brain from its body and kept alive in a vat of nutrient fluid.

A demon that is very powerful and a genius spirit who could not only feed the mind with illusory experiences but also causes a reason to reason badly e.g. to belief that 2+2=4 which could be a delusion, a spirit causing mistaken arithmetic.

A demon possibility if it were actually happening, a large number of people’s basic beliefs would not be certain. E.g. being so insane that one could not reason dreaming from reality.

In other words what if everything we are living is a lie? How could we ever be sure that everything around us is not an illusion? He speaks of the idea of the Matrix and the brain in the vat connected to a computer system that gives people experiences of taste, sight, touch, smell, hearing etc just like as it would be in real experiences.

He describes how his senses deceive him and they are not reliable. That is; the stick in the water seems to him bent when in fact is straight.

But then Descartes gets a sudden realisation, (I’m doubting my beliefs, so whatever I am doing I am doubting, but I could not doubt unless I exist so I can be sure that at any rate I exist. Doubting is just one kind of thinking, and any kind of thinking requires a thinker.” Then he arrived at a conclusion, (I think therefore I am) because whatever thinks exists, I think then I must exist.

However; if this evil genius is able to fool you about 2+4= is a 7 or a 5, might he also be able to fool you about whether you exist. Therefore, surely your belief in your own existence is not completely certain.