3.2 René Descartes and “I Think, Therefore I Am”

René Descartes (1596–1650) is one of the most famous philosophers in history and is often known as the “father of modern Philosophy”. He is also the “father” of one of the most famous statements in Philosophy: Cogito, ergo sum, which translates from Latin into “I think, therefore I am”. This simple phrase marked a turning point in the history of Philosophy.

Descartes is a rationalist, and his philosophical approach was based on the concept of “radical doubt”, that is, the theory that nothing we perceive is necessarily true. He wanted to determine whether there was anything in the world that he could know for certain as he noticed that a lot of beliefs are based on assumptions or unreliable information. To solve this problem, he developed the “method of doubt”, where he questioned everything until he found something that was so certain that it could not be doubted.

By doubting everything, Descartes hoped to find a solid foundation for knowledge. What he found was that even if everything else was uncertain, there was one thing he could not doubt: he existed. The very act of doubting proved his existence as a thinking being. He concluded:

• If I am thinking, then I must exist.
• Even if a malicious demon is deceiving me, there must be a “me” to be deceived.

Descartes stated “ubito, ergo sum, vel, quod idem est, cogito, ergo sum” meaning “I doubt, therefore I am — or what is the same — I think, therefore I am.” This realisation led to his famous statement: Cogito, ergo sum or “I think, therefore I am”. 

In other words, the fact that Descartes was able to think proved that he exists in some form because a being must be thinking in order to exist. After establishing this foundation, Descartes used reason to build a system of knowledge.