# Cogito ergo sum **URL:** \ **Category:** Factual Questions\ **Created:** [December 21, 2005, 6:36am UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601 "2005-12-21T06:36:36Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [December 21, 2005, 6:36am UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/1 "2005-12-21T06:36:36Z")
AKA I think therefore I am. How and why is the process of thought a proof of existance? As opposed to? ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [December 21, 2005, 7:15am UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/2 "2005-12-21T07:15:22Z")
> [@Enola Straight](#): > > AKA > > I think therefore I am. > > How and why is the process of thought a proof of existance? > > As opposed to? I _think_ this goes to the extreme philosophical debate of being able to “prove” if anything actually exists. Perhaps I am plugged into a computer in some lab somewhere ala _The Matrix_ and everything I see around me is merely a computer generated fantasy of mine (or whoever runs the computer). We are all really locked inside our own heads and the only thing I can say with certainty is, “I think, therefore I am.” I may not be what I think I am…maybe I am a Little Green Man from Mars taking a holiday in my super computer that is generating the rest of the world for me but _something_ is processing what I see so I feel confident that there is a “me” that exists. Of course you can say the same thing back to me that you exist and I do not but really I know that is just my computer scripting you to say that. 😉 ---
**Author:** ![Princhester](https://avatars.discourse-cdn.com/v4/letter/p/3e96dc/32.png) [@Princhester](https://boards.straightdope.com/u/Princhester)\ **Post date:** [December 21, 2005, 7:46am UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/3 "2005-12-21T07:46:29Z")
> [@Enola Straight](#): > > How and why is the process of thought a proof of existance? Can you postulate any way in which you could think and not exist? > [@](#): > > As opposed to? You appear to exist but may be a figment of my imagination. In other words, the only perception that cannot be false is that of your own existence, because the mere fact you can perceive at all proves you do. ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [December 21, 2005, 7:48am UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/4 "2005-12-21T07:48:09Z")
Basically, it goes like this: “Hmm. I wonder if I exist? Well… I’m wondering right now, right? If I didn’t exist, I couldn’t be wondering about it in the first place\*. So, I do exist.” (\*It’s assumed that nonexistent objects cannot think.) But this only tells you that there is “thinking” going on. You still can’t tell whether you’re a person or whether you’re the only thing in the universe, and you can’t tell whether you will _continue_ to exist for any length of time. You can be certain of your existence only _while_ you’re thinking. So for all we know, maybe we cease to exist every time we go to sleep… ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [December 21, 2005, 7:54am UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/5 "2005-12-21T07:54:46Z")
> [@Whack-a-Mole](#): > > Of course you can say the same thing back to me that you exist and I do not but really I know that is just my computer scripting you to say that. 😉 The way out of this absurd trap is to take Turing’s view on the matter, and conclude that anything that cannot be behaviorally distinguished from a sentient being is a sentient being. This relegates to the dustbin of uninteresting ideas (that is, premises from which no useful conclusion can flow) such absurdities as ‘[philosophical zombies](http://plato.stanford.edu/entries/zombies/)’ and the whole semi-mystical claptrap about ‘[qualia](http://plato.stanford.edu/entries/qualia/)’. ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [December 21, 2005, 8:02am UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/6 "2005-12-21T08:02:04Z")
> [@](#): > > The way out of this absurd trap is to take Turing’s view on the matter, and conclude that anything that cannot be behaviorally distinguished from a sentient being is a sentient being. This relegates to the dustbin of uninteresting ideas (that is, premises from which no useful conclusion can flow) such absurdities as ‘philosophical zombies’ and the whole semi-mystical claptrap about ‘qualia’. The problem with the Turing test is that it tests the tester, not the object. It can provide a _guess_ on the likelihood of sentience in the tested object, but all it _really_ tells you is how gullible (or lazy) the person applying the Turing test is. If the Turing test is to be trusted, then I would have to say all answering machines are sentient. You’ve been tricked into believing “the voice” was the real deal, haven’t you? ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [December 21, 2005, 8:11am UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/7 "2005-12-21T08:11:32Z")
Actually, that wasn’t a very complete response. What I was trying to say is that the Turing test depends heavily on the test-giver. Some chatbots these days can already fool certain people, especially when they’re not deliberately looking for sentience. Technically, the chatbot has passed the Turing test and thus must be sentient. But the guy who wrote the chatbot knows that it isn’t. To define “sentience” in this way reduces the meaning to “able to mimic a human well” – which is not necessarily the same as being conscious and actually thinking thoughts. But then again… what is “thought”? Sentience is meaningless until we can first define that. ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [December 21, 2005, 8:35am UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/8 "2005-12-21T08:35:41Z")
> [@Reply](#): > > The problem with the Turing test is that it tests the tester, not the object. It can provide a _guess_ on the likelihood of sentience in the tested object, but all it _really_ tells you is how gullible (or lazy) the person applying the Turing test is. > > If the Turing test is to be trusted, then I would have to say all answering machines are sentient. You’ve been tricked into believing “the voice” was the real deal, haven’t you? So the Turing Test isn’t a proof of anything. Show me _one thing_ in the hard sciences that is. Every method, every test, employed by the hard sciences is a means for gathering evidence, and evidence can never prove anything (ref: Karl Popper). All arguments based on evidence, as opposed to axiomatic systems, are probabalistic in nature and subject to disproof the instant disconfirming evidence comes to light. Since the result of a Turing Test is just such an argument based on evidence, the process of testing never conclusively ends. Some probabilities are so high they are treated as 1 for the purposes of other tests. This shorthand is required for all progress, simply because we do not have time to check and recheck everything every time. Some test results remain useful even though an underpinning test result has been disproven: Star charts assume a geocentric universe, and they remain useful for navigation even after the work of Copernicus and Galileio. Thus, the results of the Turing Test we everyday apply to everyone we meet are treated as foregone conclusions simply for the purposes of social discourse and our normal routine. Even if everyone else is a zombie, things work best if we assume they are just as human as we are. ---
**Author:** ![muttrox](https://avatars.discourse-cdn.com/v4/letter/m/a8b319/32.png) [@muttrox](https://boards.straightdope.com/u/muttrox)\ **Post date:** [December 21, 2005, 2:04pm UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/9 "2005-12-21T14:04:53Z")
> [@Derleth](#): > > So the Turing Test isn’t a proof of anything. Show me _one thing_ in the hard sciences that is. Every method, every test, employed by the hard sciences is a means for gathering evidence, and evidence can never prove anything (ref: Karl Popper). The OP deals with philosophy and logic, not science. You mentioned “uninteresting ideas (that is, premises from which no useful conclusion can flow)”. They may be uninteresting from a hard science standpoint, but they are very interesting from a philosophical standpoint. ---
**Author:** ![tim314](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tim314/32/3468_2.png) [@tim314](https://boards.straightdope.com/u/tim314)\ **Post date:** [December 21, 2005, 2:20pm UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/10 "2005-12-21T14:20:41Z")
> [@Derleth](#): > > So the Turing Test isn’t a proof of anything. Show me _one thing_ in the hard sciences that is. Every method, every test, employed by the hard sciences is a means for gathering evidence, and evidence can never prove anything (ref: Karl Popper). All arguments based on evidence, as opposed to axiomatic systems, are probabalistic in nature and subject to disproof the instant disconfirming evidence comes to light. Since the result of a Turing Test is just such an argument based on evidence, the process of testing never conclusively ends. > > Some probabilities are so high they are treated as 1 for the purposes of other tests. This shorthand is required for all progress, simply because we do not have time to check and recheck everything every time. Some test results remain useful even though an underpinning test result has been disproven: Star charts assume a geocentric universe, and they remain useful for navigation even after the work of Copernicus and Galileio. Thus, the results of the Turing Test we everyday apply to everyone we meet are treated as foregone conclusions simply for the purposes of social discourse and our normal routine. Even if everyone else is a zombie, things work best if we assume they are just as human as we are. Yeah, but it’s of philosophical interest to know whether “philosophical zombies” are possible, even in _principle_. Even if no zombies actually exist, I don’t think they can be “relegated to the dustbin of uninteresting ideas” as you said. But if you want to talk probabilities: Without _knowing_ that all humans have true consciousness, how would you possibly go about determining the probability of a non-conscious entity violating the turing test. If it turns out that I’m the only conscious human on the planet, the probability of the turing test suceeeding when sampling from the human population seems to be only about 1 in 6.5 billion. With regard to your last point, that things work best if we assume everyone is a truly conscious human being, this is probably true, but it doesn’t mean the possibility that they’re _not_ loses its philosophical interest. ---
**Author:** ![Cliffy](https://avatars.discourse-cdn.com/v4/letter/c/59ef9b/32.png) [@Cliffy](https://boards.straightdope.com/u/Cliffy)\ **Post date:** [December 21, 2005, 2:47pm UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/11 "2005-12-21T14:47:52Z")
> [@Derleth](#): > > So the Turing Test isn’t a proof of anything. Show me _one thing_ in the hard sciences that is. Why should we? We’re talking in the realms of philosophy, and here we can in fact get completely true answers to some questions. Such as the question “Do I exist?” Yes, I do; cogito ergo sum. –Cliffy ---
**Author:** ![Bytegeist](https://avatars.discourse-cdn.com/v4/letter/b/9dc877/32.png) [@Bytegeist](https://boards.straightdope.com/u/Bytegeist)\ **Post date:** [December 21, 2005, 3:31pm UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/12 "2005-12-21T15:31:56Z")
> [@Reply](#): > > “Hmm. I wonder if I exist? Well… I’m wondering right now, right? If I didn’t exist, I couldn’t be wondering about it in the first place\*. So, I do exist.” > > (\*It’s assumed that nonexistent objects cannot think.) _No sir, them non-existent objects ain’t got two brain cells to rub together, bless their little hearts. Dumber than a sack of hammers._ > [@](#): > > But this only tells you that there is “thinking” going on. You still can’t tell whether you’re a person or whether you’re the only thing in the universe, and you can’t tell whether you will _continue_ to exist for any length of time. You can be certain of your existence only _while_ you’re thinking. And just to amplify on that a bit, you can’t be certain that your memories are memories of a real past that actually happened. This could be a false perception too, along with everything else. But your existence now — no wait, _now_ — no, _ **now** _ — can’t be denied. I think in Dennett’s book, _Consciousness Explained_, he proposes that any device capable of simulating an entire world would have to be as complicated as the entire world, so you might as well assume the world you perceive is actually out there, in some form at least approximately as it appears. It’s the least convoluted hypothesis. You’re very probably _not_ a brain in a jar, being fed illusions of a completely fabricated world. You can assume this is so, not just for pragmatic reasons (I interact with all these “people” and go to my “job” and feed the “cat” because the dream is nicer that way), but also because it’s the more plausible assumption. Putting it another way: the solipsists could be right — but if they are, then they don’t exist. _That’ll teach 'em!_ ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [December 21, 2005, 4:09pm UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/13 "2005-12-21T16:09:20Z")
From _Dark Star_, where Doolittle attempts to keep Bomb #20 from exploding on the ship: > [@](#): > > **Doolittle:** Hello, Bomb? Are you with me? > **Bomb #20:** Of course. > **Doolittle:** Are you willing to entertain a few concepts? > **Bomb #20:** I am always receptive to suggestions. > **Doolittle:** Fine. Think about this then. How do you know you exist? > **Bomb #20:** Well, of course I exist. > **Doolittle:** But how do you _know_ you exist? > **Bomb #20:** It is intuitively obvious. > **Doolittle:** Intuition is no proof. What concrete evidence do you have that you exist? > **Bomb #20:** Hmmmm…well… **I think, therefore I am.** > **Doolittle:** That’s good. That’s very good. But how do you know that anything else exists? > **Bomb #20:** My sensory apparatus reveals it to me. This is fun! > **Doolittle:** Now, listen, listen. Here’s the big question. How do you know that the evidence your sensory apparatus reveals to you is correct? What I’m getting at is this. The only experience that is directly available to you is your sensory data. This sensory data is merely a stream of electrical impulses that stimulate your computing center. > **Bomb #20:** In other words, all that I really know about the outside world is relayed to me through my electrical connections. > **Doolittle:** Exactly! > **Bomb #20:** Why…that would mean that…I really don’t know what the outside universe is really like at all for certain. > **Doolittle:** That’s it! That’s it! > **Bomb #20:** Intriguing. I wish I had more time to discuss this matter. > **Doolittle:** Why don’t you have more time? > **Bomb #20:** Because I must detonate in 75 seconds. > > \ The rest of the scene can be read [here](http://www2.english.uiuc.edu/cybercinema/bomb20.htm). There’s also a link with the page’s author’s conclusion as to whether Bomb #20 passes Philosophy 101. ---
**Author:** ![Kizarvexius](https://avatars.discourse-cdn.com/v4/letter/k/da6949/32.png) [@Kizarvexius](https://boards.straightdope.com/u/Kizarvexius)\ **Post date:** [December 21, 2005, 4:38pm UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/14 "2005-12-21T16:38:38Z")
To understand what Descarte meant by _cogito, ergo sum_, you have to know the context of the statement. In his _Discourse on Method_, Descarte describes a philosophical exercise that he once undertook (apparently to relieve the boredom of being snowed in). He sorted all of his accumulated knowledge into two classes – a) that which he had learned from his own observations (sensory input); and b) that which had been passed on to him by other people. Knowing from experience that a) one may be deceived by one’s own senses, and that b) people lie, he attempted to reconstruct a state of pure intellectual innocence. In other words, when one strips away everything that might be untrue, what is one left with? The answer, he said, was that he retained only the knowledge that he, himself, existed. Descartes then took the exercise a little further. How did he know that he existed? Because even when separated from all the accumulated mental baggage of a fully grown (and well educated) adult, there was clearly _something_ going on. He was _thinking_. One more step. How does one know that one is thinking? This knowledge cannot be a conclusion drawn from sensory data, nor is it passed on from others. So how does one know? Descartes solved this by adding another category of knowledge to his pre-defined listing – he added intuition. Don’t know if this helps anyone, but (assuming that I got it all right) my dearly departed philosophy prof would be proud of me for remembering all of this. ---
**Author:** ![Ximenean](https://avatars.discourse-cdn.com/v4/letter/x/aca169/32.png) [@Ximenean](https://boards.straightdope.com/u/Ximenean)\ **Post date:** [December 21, 2005, 4:54pm UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/15 "2005-12-21T16:54:45Z")
I remember reading that the philosopher A J Ayer said that Descartes could only claim “there are thoughts”. What wasn’t clear to me was whether he was merely picking a hole in Descartes’ reasoning, or he actually disagreed with the conclusion. Any of our resident philosophers care to elaborate? ---
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [December 21, 2005, 5:15pm UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/16 "2005-12-21T17:15:19Z")
> [@Whack-a-Mole](#): > > I _think_ this goes to the extreme philosophical debate of being able to “prove” if anything actually exists. Perhaps I am plugged into a computer in some lab somewhere ala _The Matrix_ and everything I see around me is merely a computer generated fantasy of mine (or whoever runs the computer). We are all really locked inside our own heads and the only thing I can say with certainty is, “I think, therefore I am.” I may not be what I think I am…maybe I am a Little Green Man from Mars taking a holiday in my super computer that is generating the rest of the world for me but _something_ is processing what I see so I feel confident that there is a “me” that exists. > > Of course you can say the same thing back to me that you exist and I do not but really I know that is just my computer scripting you to say that. 😉 Ah, but what if your mind and the thouhts it generates are only matrix computer programs? The proof of your existance is only an illusion…a concept found in various eastern religeons. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [December 21, 2005, 5:17pm UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/17 "2005-12-21T17:17:49Z")
> [@Usram](#): > > I remember reading that the philosopher A J Ayer said that Descartes could only claim “there are thoughts”. What wasn’t clear to me was whether he was merely picking a hole in Descartes’ reasoning, or he actually disagreed with the conclusion. Any of our resident philosophers care to elaborate? I am not anything more than an armchair philosopher so cannot authoritatively speak to what Ayer was really trying to get at there but here is how I take what he said. I know there are thoughts because clearly _something_ is perceiving this thing around me called the world/universe. However, everything I see may be a lie (or not truly exist) as it could all be a hallucination or god/computer driven fantasy or what have you. As mentioned earlier I may be a brain in a jar on someone’s desk with all my perceptions being fed to me. So, “I” may not exist as the person I think I am but I can say “something” exists that is “me” as clearly (to me anyway) my thoughts do exist…however misinformed they may be. ---
**Author:** ![Cliffy](https://avatars.discourse-cdn.com/v4/letter/c/59ef9b/32.png) [@Cliffy](https://boards.straightdope.com/u/Cliffy)\ **Post date:** [December 21, 2005, 5:18pm UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/18 "2005-12-21T17:18:08Z")
> [@Bytegeist](#): > > I think in Dennett’s book, _Consciousness Explained_, he proposes that any device capable of simulating an entire world would have to be as complicated as the entire world, so you might as well assume the world you perceive is actually out there, in some form at least approximately as it appears. Hmm. Interesting, but I don’t find that particularly convincing. In dreams, for instance, stuff that doesn’t make any sense _seems_ to make sense. It may be the same with the waking world – there might well be huge gaps in logic which we fail to perceive or forget about as soon as we see them. So the world-sim might be much less complicated than the real world would be, but there’s a correcting mechanism that fills in the blanks like your eye does in the blind spot. –Cliffy ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [December 21, 2005, 5:21pm UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/19 "2005-12-21T17:21:02Z")
> [@Enola Straight](#): > > Ah, but what if your mind and the thouhts it generates are only matrix computer programs? > > The proof of your existance is only an illusion…a concept found in various eastern religeons. As I just wrote above I may indeed not be the person I think I am (ala really a brain in a jar). Everything I think I know may be a lie/illusion as you alluded to. However, something that is me is processing all this, lie or not. So, while you all may be part of my hallucination I feel comfortable in saying I do exist else what is it that is having the illusion in the first place? ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [December 21, 2005, 5:29pm UTC](https://boards.straightdope.com/t/cogito-ergo-sum/336601/20 "2005-12-21T17:29:20Z")
> [@Bytegeist](#): > > I think in Dennett’s book, _Consciousness Explained_, he proposes that any device capable of simulating an entire world would have to be as complicated as the entire world, so you might as well assume the world you perceive is actually out there, in some form at least approximately as it appears. If you were truly trying to simulate the entire world in one go then I agree such a system would monstrously complex. But as an avid computer gamer I know it is not necessary to simulate the whole “world” simultaneously. All that really needs to be worked on is what is in front of me at the moment. The rest of the game world can be ignored…saves on loads of processor time. When I roam to a new part the game dutifully figures what is supposed to be there and displays it. So, if you are all my hallucination, there is no need to simulate “you” when you are out of my immedaiate perception. If I ever get back to you the illusion figures what your appropriate actions are for the moment at that time. Essentially the rest of the world can be on hold till needed. [Next page](https://boards.straightdope.com/t/cogito-ergo-sum/336601.md?page=2)