Famously Descartes said 'Cogito ergo sum'. I'm a bit puzzled by this. I do not need to think in order to assert/understand/intuit that I exist: when I wake up in the morning I immediately intuit that I exist. I see this understanding as a form of inner experience.

I can imagine myself as a bat, and as a bat, I do not have access to logic, formal or otherwise, but I would say (though as a bat I couldn't articulate this), that I would still feel I exist.

Descarte, as a human being, and as a philosopher, is in my opinion, privileging a quality peculiar to humans: thinking.

My feeling is, that Descarte is being seduced by the axiomatic method in mathematics to attempt a similar method in philosophy, that he's trying to conjure something out of nothing.

My preferred statement would be 'I am', or even more stripped down, 'am': I don't think a bat would conceive of itself as an 'I'.


You're reading Descartes out of context; he doesn't just say "cogito ergo sum" and go home, he says it in the course of an argument. I'm not going to rehearse all of the steps of the argument here-- the Meditations on First Philosophy are readily available, and easy to read-- but in broad strokes, he's asking: what do we know indubitably? Is there any kind of knowledge that it is impossible to doubt?

For example, I see the cup on the table in front of me, but when I am dreaming, I often see cups? Can I be certain, beyond any shadow of a doubt, that I am not dreaming now? No, he argues-- sense perception can be doubted.

But, can I doubt that I exist? Doubt is a form of thinking, and if I am thinking, I indubitably exist. Thus, no matter what else I doubt, I cannot doubt that I exist.

Whether I am a bat or a person is not really relevant to the problem; if bats are capable of doubting their existence, they fall under the cogito. (If they're not, then the issue doesn't come up for them-- Descartes is not aiming to investigate bat epistemology.)

I suggest you read the Meditations; they are fascinating, and brief, and a wide variety of secondary literature exists to help you along the way. And, what's more, Descartes published a number of responses to objections from his contemporaries, so we can see exactly how we would respond to a number of possible refutations.

  • I haven't read the meditations, and yes, you're right criticising a philosophy on the basis of one aphorism is a bit silly. On the otherhand, the argument that you've just outlined is very well-known, and I am aware of it. I'd be interested in bat epistemology if I thought it possible, I don't. I'm using this example to see what would happen if you deny Descartes doubting thomas language & logic. Apr 12 '12 at 18:09
  • It still appears to me that you are misunderstanding Descartes's project. He's not trying to come up with a minimal statement like "I am"; rather, he is trying to show that there is transcendental limit to doubt (which can then be used as a foundation upon which other indubitable knowledge.) If you deny Descartes "doubting Thomas" language and logic, you've eliminated his project-- there's nothing left for him to do. His project here is all about logic and doubt. Apr 12 '12 at 19:15
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    @dorfman:You're right, I realised I had removed the possibility of his project after I'd posted my last comment. Apr 12 '12 at 19:33

I think your response is the intuitive one, but your goal is more about causation. We want to say that we think because we exist, and it's not our thinking that causes us to exist.

But Descartes isn't talking about causation, he was trying to justify knowledge. If perception can be doubted, all concepts fallable etc... then on what foundation does any knowledge lie, he asks.

About the existence of his body, he says maybe it could be like a dream - that the body doesnt really exist and maybe he's dreaming it (a demon could be tricking him, he said). But when he came to cognition, he surmised that that cant be doubted, because, to him, it's a logical necessity that thought requires a thinker.

So in the lingo, thinking is sufficient but not necessary to exist (as a mind/soul). How a mind/soul exists, if at all, is another question for another age though.

  • So, from what you're saying I'm guilty of interpreting Descartes statement too literally. But, even given he's tackling the question of knowledge, I'd argue that he's engaging in circular reasoning. To even make this statement, he's already having to import in language - which is a publicly constructed phenomenon. Apr 11 '12 at 6:22
  • Not so much "literally" but with different motivations. Michael's comment below is spot on and follows the movements in the Meditations very well. Descartes, I don't think was really interested in metaphysics (probably to his credit). It's like the Meditations was a bit of an intellectual exercise done in spare time to put skeptical questions to rest, so he could get on with science. I think the catchiness of "I think, therefore I am" has made his work seem more serious than it was.
    – JKim
    Apr 11 '12 at 12:10

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