We have all heard this phrase in some form or another but even when I, myself, tried typing this little sentence into google to see what would come up, I was surprised to see that no one could give an explanation that wasn’t lengthy or straightforward. So I’m going to try my hand at explaining this classic statement.
Who said it?
Rene Descartes is the man credited to these few words. The quote, originally written in french, comes from The Discourse on Method, but also appears written as the famous Latin, “Cogito ergo sum,” in his Meditations on First Philosophy, which was an attempt to find foundational truths for knowledge. The book contains six meditations that attempt to discover what is real by first doubting absolutely everything and starting from scratch. In this way, Descartes starts at the bottom and works his way up into believing in the existence of worldly things.
What else do I need to know?
In the First Meditations Descartes explains why he can call his beliefs into doubt, since his beliefs have deceived him before — I think we can all relate to one experience where our beliefs have been totally wrong and we feel the way old Descartes feels here. He argues that perhaps he is currently dreaming or that God is actually a deceiving demon, or that he is simply crazy. This gives him reason to be skeptical of all his beliefs, which leads us into the Second Meditations. Here is where he convinces himself that nothing of the world is real. He essentially disbelieves everything that can possibly be called into question and whittles existence down into nothing. Then, he says as follows:
I have convinced myself that there is nothing in the world — no sky, no earth, no minds, no bodies. Doesn’t it follow that I don’t exist? No, surely I must exist if it’s me who is convinced of something. But there is a deceiver, supremely powerful and cunning whose aim is to see that I am always deceived. But surely I exist, if I am deceived. Let him deceive me all he can, he will never make it the case that I am nothing while I think that I am something. Thus having fully weighed every consideration, I must finally conclude that the statement “I am, I exist” must be true whenever I state it or mentally consider it. (Descartes, Meditation II: On the Nature of the Human Mind, Which Is Better Known Than the Body).
Wait a minute, Where’s the quote!?
It’s there, trust me! “I am, I exist,” is used here by Descartes to express the same thing. Meditation II is often called the cogitio for the reason that the words “I think, therefore I am,” can readily be explained with this passage. Essentialy, “I think, therefore I am” and “I am, I exist,” mean the same thing.
Okay, So what does it mean?
If you read the above quote from the Meditation II you see that Descartes has disproved everything that he is used to believing in. When there’s nothing left he still is left with himself and nothing else. Regardless of whether or not he is being deceived by some demon or his beliefs are wrong, he is able to see that even if he has the ability to doubt something he must be existing to even doubt it in the first place. The fact that he can think is what assures himself of his own existence, and a deceiving god cannot negate that. From this point on, Descartes can continue in his examination of reality without worry that he is by all means existing.
“I Think, Therefore I am” is used in most intro classes to gets across the real meaning of what the cogito (Meditation II) means — A deceiver can’t deceive me of my existence, for if he were I wouldn’t exist! Although, the true quote comes from Descartes Discourse on Method, it is easier to explain it with this example. The Meditations on First Philosophy is a wonderful piece of literature that’s extremely interesting for anyone to read. If anything I said in this post sparks your interest, then I suggest you read this whole thing through yourself. That’s all for now, I hope you all now have a better understanding of what Descartes was trying to say.
So, do our old pal Descartes a favor folks and keep thinking, lest you may cease to exist!