Cogito Ergo Sum, I think therefore i am
Cogito ergo sum, or its translation, “I think, therefore I am,” is a frequently-quoted line from well-known mathematician and philosopher René Descartes. I’ve noticed that it often seems to be misunderstood; this post is a brief outline of the idea and some of my thoughts on it.
When concluding cogito ergo sum, Descartes was attempting to determine what truths, if any, could be truly known beyond all doubt. He had a tough time of it, finding that almost everything he could think of was subject to at least some degree of uncertainty. He imagined a scenario involving a demon playing a trick on the senses – that the world might not really exist, and the demon was magicking up an illusion for him. A modern equivalent would be the Matrix or being in a computer simulation.1 Today, the term for being sceptical about all things except one’s own existence is known as ‘Cartesian doubt’, an eponymous tribute to Descartes.
Cogito ergo sum was Descartes’ answer to his question of what could be said to be definitively true. The only thing a person thinking about knowledge can know exists, Descartes concluded, is that they themselves exist, or else there would be no thinking. Another way to put it is that if we know a subject is performing an action, then we know that the subject must exist (or else they could not be performing the action).2 Think, or rather, experience, feel, etc., are the only actions we know are happening, and they must involve a subject – us (or, more precisely, me and maybe you as well). So, strictly speaking, cogito ergo sum is not the only truth that can be known; we can also know about the existence of thoughts and feelings: I know that at least one feeling exists because I feel it; I know that at least one thought exists because there is one in my mind; I know that certain sensations exist because I am sensing them, etc. All of these require subjectivity, therefore there must be a subject (‘me’). I do not, however, know for certain
When concluding cogito ergo sum, Descartes was attempting to determine what truths, if any, could be truly known beyond all doubt. He had a tough time of it, finding that almost everything he could think of was subject to at least some degree of uncertainty. He imagined a scenario involving a demon playing a trick on the senses – that the world might not really exist, and the demon was magicking up an illusion for him. A modern equivalent would be the Matrix or being in a computer simulation.1 Today, the term for being sceptical about all things except one’s own existence is known as ‘Cartesian doubt’, an eponymous tribute to Descartes.
Cogito ergo sum was Descartes’ answer to his question of what could be said to be definitively true. The only thing a person thinking about knowledge can know exists, Descartes concluded, is that they themselves exist, or else there would be no thinking. Another way to put it is that if we know a subject is performing an action, then we know that the subject must exist (or else they could not be performing the action).2 Think, or rather, experience, feel, etc., are the only actions we know are happening, and they must involve a subject – us (or, more precisely, me and maybe you as well). So, strictly speaking, cogito ergo sum is not the only truth that can be known; we can also know about the existence of thoughts and feelings: I know that at least one feeling exists because I feel it; I know that at least one thought exists because there is one in my mind; I know that certain sensations exist because I am sensing them, etc. All of these require subjectivity, therefore there must be a subject (‘me’). I do not, however, know for certain