“I Think, Therefore I am” Confused: What does this Phrase Mean?

imagesWe 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!

Posted in Philosophy.


  1. Thank you for your succinct explaination of this often misunderstood quote. Or should I say miscedited quote? Since Descartes is not the one who actually made this statement, who should be credited with this line? Or should Descartes receive the credit since he so eloquently came to the conclusion, “I am, I exist” ? Should not the actual creator be praised for his or her articulate tongue? But I forget, I exist because I can think, not because I can speak or write. To you Joseph, thank you for inspiring thought!

  2. Existence in a reality and in a virtual reality … it makes you think but still does not make you exist in a virtual reality.
    Existence seems to imply total control of these three questions :
    how (past), what (present) and why (future).

    In a virtual reality, completely and perfectly constructed, we would have full control of these three questions.
    But in <>, we only can influenced our “what” depending on what we believe our “how” was and our “why” will be.
    Great website.

  3. Very nice, except you are mistaken that the words were misquoted. the exact quote is- Je pense donc je suis and is found in Discourse On Method, then again in the Latin “cogito ergo sum” in Principles of Philosophy.

  4. Thanks to Josh we are being reminded that English or any other language is not the source of thoughts contained in ideas but only the form in which they are expressed more often quite imperfectly because of all the limitations inherent in many languages and the limited abilities of many to use even one language correctly.

    Objective reality exists without any human having to understand what reality is or ever wanting to know how far removed their own subjective existence from any form of reality even is. The human mind is so frail to make it possible for large numbers of the world’s population to follow various super natural myths as religions even though all of nature was never dependent on anything humans ever created, may it be art, economic theory, politics, mythology or religion …

  5. it is my belief as a result of existing for some time that I am insane, that is some of the time, sometimes most of the time, as I live I am constant awareness of the trail I leave behind of clues that support my statement, If I exist has such a profound insight I would be succeeding in a more holistic path which I am not, as far as I know I am here to be frustrated by everything, I do not know why, as I am part of the Universe I do not know why I should be so frustrated as I know so little, therefore why should I have this concern? as I am born to be in constant problems with all that I know, what alarms me more than anything is I do not know why I was not born say a earthworm where I could eat people with impunity, if one becomes nothing why would it seem as if one comes from nothing to be something?, if I am part living death in life can I be living in death as alive?. don wreford.

  6. what does the overall meaning? You say who says it, and where it is. But If I where to use it in something else, what would the actual meaning be!

    • I’m not quite sure what you mean. I believe I explained this phrase above by appealing to where it is located in Descartes Meditations. It’s not like a proverb that applies to certain situations, it’s a logical point made by way of skepticism. So, I couldn’t explain to you what it means if you “wanted to use it somewhere else,” because it isn’t really to be used anywhere else.

  7. It seems everybody and their cat likes to drop the quote in question, but too few can offer an interpretation of it or why it’s relevant.
    Simply, it’s a statement that one “exists”, and is no simply an automaton or an illusion.

    Here is my take:
    Original – cogito ergo sum
    In English – I think therefore I am
    For the laymen – I can be certain I exist when I am thinking.

    it’s that simple, really!

  8. “‘I think therefore’…I am confused and have a headache.”

    –dahszil, circa 2002

    (one of the thousands of posts on the old, legendary, Yahoo per article, message boards under one of dozens of message board nom de plumes used by dahszil)

  9. Questions like this were often asked during the time of the Buddha. He discouraged such speculation which only causes more mental confusion. His method of discovering reality was to be aware of the present moment and all it contains. So, in the case of Descartes and existence, the present moment is one of Doubt. Know then that Doubt exists, rather than being the doubter and giving Doubt food to feed on! This awareness of the present can be refined until it is continuous and we are living in the present. However, it is not as simple as it sounds – thinking about doubt is not the same as being aware that doubt has arisen!

  10. Descartes deceives himself in thinking that, because he can think, his existence is assured. Why couldn’t he see that without his being, he could not think. First one has to be, then one can think. There is no thinking without being.

    He posits that thinking precedes being. That is simply wrong logic- like putting the cart before the horse. Why couldn’t he see that the horse pulls the cart, not the other way around?

  11. It may be possible to be and not think. It seems that most of human history is one of being without thinking. Perhaps in a far end of the cosmos or in another universe thinking may require no physical, tangible presence. Not even the 0’s and 1’s in subatomic form which are the basis of artificial intelligence. perhaps rocks think. Then, assuming Descartes was referring to homo sapiens, then Descartes was at least partly incorrect. When I write in this other or non reality i do not end up with a headache, funnily enough. And I am not in a “theatre of the absurd” mode which is something else but similar.

  12. Beautiful.
    It makes me wonder though. If he truly believed that nothing exists with the exception of himself, what could have led him to believe that there is a deceiver? It seems to me that three logical conclusion would be not only that he is, but must also be the deceiver.

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