Monday, March 19, 2007

I think therefore I am

Now that we understand (assuming we do) the context of Descartes' famous "I think therefore I am" argument, we might want to know if it does what Descartes thinks it has done. Does it really remove all possible doubt from the propositions "I think" and "I exist"?

One possible response would be to say that you could just as easily say, as in the Monty Python philosopher's drinking song, I drink therefore I am. But "I am drinking" clearly does not pass the Satan test. Satan could deceive me into thinking that I am drinking; in fact, beer could do the same thing. Enough Miller Genuine Draft will cause you to pass out, in which case you may dream of more MGDs even though they don't exist.

But does Descartes prove that there is a something that does the thinking, as opposed to just that thinking is going on? The Stanford Encyclopedia of Philosophy says:

Many a critic has complained that in referring to the "I" Descartes begs the question, since he presupposes what he intends to establish in "I exist." Bertrand Russell objects that "the word ‘I’ is really illegitimate"; that Descartes should have, instead, stated "his ultimate premiss in the form ‘there are thoughts’." As Russell adds, "the word ‘I’ is grammatically convenient, but does not describe a datum." (1945, 567) Accordingly, "there is pain" and "I am in pain" have different contents, and Descartes is entitled only to the former.

But my problem with this objection is that just because we can say "there are thoughts" and not actually say that someone is thinking those thoughts doesn't make the suggestion coherent. As Russell should have known, you can say "Floyd the barber shaves everyone who doesn't shave himself in Mayberry," but only when we ask whether Floyd shaves himself do we discover that the suggestion is not coherent. Does the term "pain" really mean anything if there is no one experiencing the pain? We can redescribe the pain in such a way that it no longer refers to an individual having the pain, (the firing of C-fibers in the brain) but if we do it seems we lose what is meant by pain. (This would be a good way to solve the problem of pain, if it were legitimate. "You think these people are suffering terrible pain, and that God shouldn't allow it. But really all that is going on is that people's C-fibers are firing.)

In short, I think that Descartes argument that there must be a thinking subject is a successful argument. It's the next stages of Descartes' programme that I have trouble with.


Victor Reppert said...

Bill Vallicella has written a response to my discussion, and got a response from Rob, on his blog.

Victor Reppert said...

You can see the post at

Jason Pratt said...

As someone who relies very heavily on an approach similar in result to Descartes (the method isn't exactly the same), I will clarify that _I_ at least am very careful to demonstrate that in reaching "I think, therefore I exist", I do _not_ mean to claim that I have therefore proved I exist. Russell is, in one way, right--that would be begging the question in favor of a presumption.

I cannot (strictly) prove that I can think. (As Lewis himself pointed out in MaPS--much to the ignorance of many critics against his conclusions {g}--that would be circular and therefore impossible as a legitimate conclusion. "One cannot prove that there are such things as proofs.")

What I _can_ prove, is that I am presuming this claim (I can think--in various basic ways, down to "I can act") whenever I try to make any argument, even when the argument would otherwise involve a counterclaim to the presumption. The presumption is necessary--only nonsense follows if I try to deny it (either via counter-presumption or via conclusion).

Consequently, I _should_ accept it formally to be true (even though I cannot formally prove it to be true); and subsequently, I _should_ accept as true whatever implications follow deductively from the truth of the presumption.

"I exist", for instance, is necessarily, though also somewhat generally, entailed in the presumption "I think", once the implications of "I think" are examined; but "I exist", though also necessary for purposes of argument, is not related integrally to the argument itself, in the way that "I think" is.

One of the deductions which follows, however, from the necessary presumption of my own existence as an active (not merely reactive) thinker, is that I should deny atheism to be true, and affirm not-atheism instead.

Which is why some critics, evidently seeing this clearly enough once the logic is layed out more fully--I haven't really explained why the conclusion follows, here, btw--attempt to play the 'mutually assured destruction' card and call all human rationality into ultimate worthlessness. Except for their _own_ rationality at the time they make the claim... {cough}{g!}

The extent to which I've seen some people go to get away from this conclusion is pretty amazing; though to be fair I suspect that at least part of the motivation is to avoid what looks at first glance like a path leading to a highly uncharitable and unfair religious belief. I can sympathize with the feeling there, but damning the minds of all men--except one's own mind--is not the proper response. (This attempt, and its obvious self-refuting failure, is not to be confused with other attempts at oppositional criticism, of course.)


slaveofone said...

"I" is a "person" or a "personality" statement. And "thinking" is an aspect only of personality (non-persons/non-personalities are not characterized by thought). Although Descartes doesn't prove beyond any doubt that there is an "I", he is required to acknowledge a personality or person by using a term descriptive only of a peron or personality: thinking/thought.

Because thinking/thought is self-evident, it is self-evident that there is a person or personality.

interlocutor said...

I think the problem is with the subject-predicate form. When thoughts happen is it generally a subject ("I") performing an action ("think") or are thoughts first? Do we normally say, "Okay, I'm going to have a thought now," or do these thoughts happen and then as we reflect on them we add the subject?

Isn't the point of Kant's transcendental unity of apperception just that the "I think" CAN accompany any thought, not that it is underlying every thought? Sartre seems to make a good case that the "I think" is only added to reflective conscious experiences (e.g. my initial conscious experience is of a red apple; I have an experience, "RED!"; now, I can move onto a second level and say say, "I just thought, 'RED!'"; but it is only at this second level that the "I" is added to the experience).

Is it not, then, more reasonable to follow Russell and conclude "there are thoughts" because this is prior to any subject? Perhaps Husserl had the better solution of simply bracketing the question of the ontological "I" and dealing only with acts of consciousness. But, again, Sartre seems to make a good case that this can't be done.

I can't see how Descartes' project was completely successful in establishing the existence of the thinking subject.

Edwardtbabinski said...


What is "pain?" (Since you mentioned it.)

What is "consciousness?"

How many different types of pain and consciousness are there?

There's intense pains to bearable pain to simply feeling a little cold or hot or pressure, and maybe even sliding into pleasure on the other side of the scale of things we experience with our sense of touch.

Consciousness can also lay along a scale (or even lay along a branching tree perhaps) from unconsciousness to semi-consciousness to hypnotic or automatic or sleep-walking or reflexive consciousness to consciousnesses that involve greater and greater awareness of certain things, though none of us is ever completely aware of the entire wealth of data bombarding our senses each second, nor are any of us completely aware of the entire lifetime of "stuff" that lay inside our own brain/minds and upon which are "choices" appear to be based, and which allow us to spew forth "answers" that we assume are obvious to us.

We aren't even completely aware of the words we shall write before they come to us, seemingly out of thin air. There is a moment before such words come into our brain/minds or before we type or write or speak them. What is happening during that moment?

Edwardtbabinski said...

How about the phrase,

"I am, therefore I think?"

And asking what it means "to be?"

Blue Devil Knight said...

I think Russell is right. Victor's argument is tough to support without a demon-surviving argument that for every thought there is a corresponding "I." The claim that any experience has to be experienced by someone is a nontrivial psychological theory, at least as controversial as the existence of the external world. Since the cogito doesn't give us the latter, it can't give us the former.

Therefore, Bertrand Russell is God.

Unknown said...

"Floyd the barber shaves everyone who doesn't shave himself in Mayberry," does not preclude his shaving Mayberrians who do shave themselves, such as someone shaving himself in the morning and then stopping by Floyd's in the evening for a second shave. Hence there's no contradiction when Floyd shaves himself.

Unknown said...

Edward: Ayn Rand said "I am, therefore I'll think" - which was correct for her. But the I will part is volitional; one can exist but choose not to think.

Charles Lee said...

"I" must exist in order to think, and maybe more to the point, to be aware that I am thinking. It is the self reference that makes it real, and a "thing that thinks" takes it out of self reflection and views one's self in the third person almost, as seeing someone who is seeing us thinking, although that person could be deceived into thinking that they see us.
Only "I" can be assure that "I" exist as a direct conclusion from the knowledge that "I" am thinking. If I didn't exist I could not be thinking, doubting, dreaming, or drinking, although only the first is conclusive; all else if based on my awareness that I think. In fact, this is only meaningful in the context of self of self awareness because beings that are not self aware cannot think of themselves as being anything.

OMO said...

Charles Lee said:
"I" must exist in order to think, and maybe more to the point, to be aware that I am thinking."

You do not need the "I" to think.
You do not need the "I am" to be or exist. "I" think all the time but I do not know or cannot experience those thoughts as exclusively "my" thoughts. I NEVER tell myself "these are MY thoughts, or "those are HIS thoughts." The words "me," "you," "she," "he," "his," "her," are all variations of the word I- ie., we use those words to describe a single person or entity.

Words, any word, cannot PROVE anything. "I" cannot be proved.

"Words are made to declare something; where they are, by those who pretend to instruct, otherwise used, they conceal indeed something; but that which they conceal, is nothing but the ignorance, error, or sophistry of the talker, for there is, in truth nothing else under them." Locke.


"The person is non-existent, a non-entity. In fact, there is no person, or there only one person. Only God can be said to have a personality, because only God can have a centre. We have no centres at all." (Rajneesh 1977)

goldigit said...

There is a problem with Descartes' basic philosophical argument that few people pick up on. Since it attempts to get to the root of existence, it follows that it must be in accord with our contemporary understanding of the nature of existence. There have been many incredible discoveries in science since Descartes formulated his ideas, and though some might say "what has science got to do with philosophy?", I would say "everything." The two are inextricably entwined, especially when it comes to matters of reality and our perception of it. Quantum mechanics has proved to be an effective tool in many technological advancements of the past decade or so, in ways that defy reasonable explanation. It works but it shouldn't, certainly not in regard to conventional thinking -- ah, there's that word... 'thinking'. Who would have 'thought' that observation could affect result? And who would have 'thought' that a sub-atomic particle could just change velocity or position on a whim... in no time at all? Certainly not me, and certainly not Descartes, it seems. So what am I saying? Well, I guess it means that there can be no certainty about anything at all. We, our bodies, our brains, our thoughts, might be nothing more than holographical quantum representations. Who knows? Can anything at all really be proved anymore? I 'think' not. But what is a 'thought' other than an effort to convince us of reality? Something which has no meaning in a nonsensical and (apparently) multi-dimensional multiverse.