_004 Descartes & Cogito Ergo Sum

How can we be certain that we see what is really in front of us and not something different? How can we trust our senses or our intuitions about anything in the world? How can mirrors be real if our eyes aren’t real?

René Descartes, a 17^th Century French philosopher attempted to “reboot” all of philosophy, without making any assumptions about the way the world is. This is known as radical doubt – he claims that it is entirely possible that an evil demon is manipulating everything around us to make us believe that which isn’t true.

Even statements like 2+2=4 must be doubted as the demon may just want us to believe that. Everything must be taken off the table before we can start putting things back on, and he only wants to put on things which he knows with certainty, not just probability.

For Descartes, there is one thing that is beyond doubt – that we are thinking. For even if we are to doubt that we are thinking, that is itself a thought. And if there is a thought then we must exist in order to think it.

This is the origin of his famous quote:

Cogito Ergo Sum – I think, therefore I am

But this is not the only thing that this proposition suggests:

It also means the mind must be separate from the body, since the mind has been proven even though the body has not. So a mind must be able to exist independently from the body

Finally, through a much longer process, he deduced that certain things must be true because their definition necessitates it – like that a square must have four sides. He then says that God is similarly true by definition (Ontological Argument¹). From this, he can safely say that an all loving God wouldn’t let his senses be deceived by an evil demon, so all knowledge has been restored with certainty

His ideas do have their weaknesses though and many have challenged even these simple claims: Nietzsche stated that Descartes never in fact proved that he existed, since he didn’t prove that he himself was the one that was thinking, only that there were thoughts. His thoughts could have been generated by an external entity like The Matrix, or even the Evil Demon, which means that the rest of his proof is invalid.

Others have challenged the idea that the mind and body are separate, even scientists have conducted experiments on the brain which suggest that the mind is directly linked to the body.

In conclusion, whilst Descartes’ logic may not be airtight, he brought forth a method of rigorous questioning and rejection of assumptions which established him as the father of modern philosophy, inspiring thinkers like Hume, Kant and Nietzsche (even if it was just to refute him)

Word Count: 467

¹http://plato.stanford.edu/entries/descartes-ontological/

Meditations on First Philosophy = Meditationes de prima philosophia, trans. George Heffernan. Notre Dame: University of Notre Dame Press. A literal translation of the six Meditations proper, with facing-page Latin.