Other Minds Skepticism Last time we talked about what might be called “global” skepticism– skepticism that anything at all can be known. We considered several responses to arguments for skepticism: accepting skepticism, accepting idealism, or simply denying that skeptical arguments have any force (Moore’s response). Nobody’s a Skeptic Whatever we think about the particular responses to skepticism, most contemporary philosophers think that skepticism is neither very compelling nor very worrisome. We do know things, even if it’s difficult to say how that’s possible. This is part of Moore’s “common sense” legacy. Local Skepticism In addition to “global” skepticism there are various “local” skepticisms: instead of claiming that you can’t know anything at all, a local skepticism says that you can’t know anything about a certain topic. For example, you might think that it was impossible to know anything about God, even though you could know lots of other things. Global Skepticism Global skepticism presents arguments that apply generally to any claim. For example we saw that Sextus Empiricus thought that there were equal reasons for and against any claim. And Descartes argued that if we were being deceived by an Evil Demon, he could trick us about almost anything (except that we existed and that we had the experiences we did). Local Skepticism Local skepticism instead focuses on specific features of the topic in question that are supposed to make knowledge about that topic impossible. For example, someone might claim that God is unknowable, because She transcends reason and logic, being their creator, or because the human mind is too weak, or because we can’t experience God directly. Two Skepticisms In today’s class and next Monday’s class we are going to consider two different local skepticisms: Skepticism about Other Minds: We can’t ever know that other people have minds. Skepticism about Induction: We can’t ever know about unobserved phenomena. OTHER MINDS: THE PROBLEM Asymmetry The way we have of finding out about our own minds is very different from the way we have of finding out about other people’s minds. To find out what I think, or feel, I might close my eyes and concentrate on my thoughts or sensations. This is called “introspection” which just means “looking inward.” Asymmetry However, I can’t “look inward” at your thoughts and feelings. If I want to know what you think, I have to observe how you act, and what you say. The same is true if I want to know how you feel. This would be silly in the first-person case. I don’t have to look at how I act in order to find out what I believe. Who Has a Mind? But does the fact that other people behave in certain ways really justify us in believing that they have minds? You presumably think that some things don’t have minds and some things do. Cats have minds, and maybe fish do too, probably not worms and definitely not bacteria, or rocks. Who Has a Mind But how do you know these things? Panpsychists believe that everything has a mind, including trees and rocks and gamma radiation and empty regions of space. “A rock doesn’t have a mind,” you might say, “it doesn’t cry out when I kick it.” But the panpsychist can just say: “I said it had a mind, I didn’t say it had a mouth!” Who Has a Mind? Or how do you know that cats have minds? Descartes, for instance, believed that only humans had minds, because the mind = the soul, and God had only given souls to humans. “The cat cried out when you kicked it– isn’t that proof that it feels pain?” “No,” Descartes would say, “I could build a robot that did that, and the robot wouldn’t feel pain.” Philosophical Zombies A philosophical zombie (as opposed to the ordinary kind of zombie) is a thing that is in all respects exactly like a person– it eats, and sleeps, and drinks, and has conversations, and goes on dates. But it has no “inner life”– there’s nothing it’s like to be a zombie. It feels no pain (even though it cries out when you strike it), and it has no beliefs (even though it argues with you forcefully about various subjects). The Epistemological Problem One way of stating the problem of other minds is just this: how do you know that other people aren’t philosophical zombies? What possible argument can you give for attributing mental states to them? Local Skepticism This isn’t global skepticism– the claim isn’t that you can’t know anything. You might think that knowledge = justified true belief. And you can be justified in believing that you have hands, for example, because you see them. If it’s true that you have hands, then you know you have hands. The problem of other minds asks: what justifies you in believing other people have minds? Unusual Justification If there is a justification, it can’t be an ordinary one: It’s not that you see, smell, taste, hear, or feel other people’s minds. And you don’t “directly” experience them either, in the way you do your own. The Conceptual Problem In addition to the epistemological problem of other minds (“How do we know?”) there is also a conceptual problem of other minds: how do we even think of other minds than our own? My personal experiences allow me to think about my own mind, and the appearances of physical objects give me a way to think about them: but I don’t experience other minds, and they don’t cause appearances in me. How can I even think the thought “You have a mind”? The Conceptual Problem That might sound a little weird. I know what it is for me to have a mind. So when I think “she has a mind” I am just saying that’s how it is for her. But the skeptic thinks this is a verbal trick. Wittgenstein famously remarked that it’s like saying “I know what it is for it to be 5:00pm in Hong Kong, therefore I know what it is for it to be 5:00pm on the sun.” ANALOGY Bertrand Russell (1872-1970) Russell Bertrand Russell was a British aristocrat (the 3rd Earl Russell) who made lasting contributions to logic, mathematics, and philosophy. Together with G.E. Moore, he helped lead British philosophical thought away from Absolute Idealism towards a pluralistic realism. Arguments from Analogy Russell’s suggested solution to the problem of other minds is an argument from analogy. According to Russell, the argument takes this form: Only A’s cause B’s I observe a B_________________________ Therefore, I know that B was caused by an A. Thunder and Lightning Here’s an example that’s not about minds: Only lightning causes thunder. I hear some thunder in the distance (but I didn’t see any lightning)._______________________ Therefore, there must have been some unobserved lightning that was the cause of the thunder. Analogy Argument for Other Minds And here’s how the argument works for minds: Premise 1: Only the sensation of thirst causes water-drinking behavior. Premise 2: That other person is drinking water (but I don’t experience their thirst).________ Conclusion: Therefore, that person’s waterdrinking behavior was caused by an unobserved thirst. New Analogy Argument Russell doesn’t explicitly say this, but he seems to suggest a different argument from analogy as well: All A’s cause B’s. I observe an A (but can’t observe B). Therefore, there was an unobserved B New Analogy Argument Here’s how this might work for the mind: Premise 1: Walking through the desert for four hours with no water causes a sensation of thirst. Premise 2: That person walked through the desert for four hours with no water._________ Conclusion: That person is thirsty. Both Arguments Together And we can combine the two forms of argument Premise 1: Walking in the desert causes thirst AND thirst causes drinking water. Premise 2: That guy walked in the desert AND drank water.___________________________ Conclusion: Therefore, that guy was thirsty. Evaluating the Argument Premise 2 is obviously acceptable: as long as we’re not being global skeptics, we’ll be inclined to think that other people are in fact drinking when it looks like they are, or that they walked through the desert, when it looks like they did. Russell’s Postulate What can be said in defense of premise 1? Russell proposes a postulate: “If, whenever we can observe whether A and B are present or absent, we find that every case of B has an A as a causal antecendent, then it is probable that most B’s have A’s as causal antecedents, even in the cases where observation does not enable us to know whether A is present or not.” Russell’s Postulate So the idea is this. Only in my own case can I ever observe both a sensation of thirst and water-drinking behavior. (For others I can only observe drinking, not thirst). But every time I drank water, it was because I was thirsty. Therefore, I can conclude that most water drinking behavior is caused by sensations of thirst, even though I can’t observe them in other people. Induction on One Instance Russell’s postulate seems to break down in certain scenarios. Suppose you haven’t been over to anyone else’s house, you’ve only been to your own house. At your house, everyone takes off their shoes at the door– nobody walks around at home with their shoes on. It doesn’t seem safe to conclude that at everybody else’s house everyone takes off their shoes. You’d need to look at more than just one house (yours) to conclude that. Induction on One Instance Here’s another example. In the U.S., servers come to your table to take your order, ask you if you need refills, bring you the check, etc.– and you never have to call them over. In fact, Americans would probably think it was rude to call across the restaurant to get service. Suppose you’ve only ever lived in America. Can you conclude that this is how it is in every other country? It seems you’d need to look at more than just one country to draw that conclusion. Induction on One Instance Russell wants us to conclude that certain sensations are usually present in others when they behave in certain ways, because that’s how it usually is for us. But if I’ve only ever looked at my mind, or my house, or my country, is that enough to draw a conclusion about everyone’s mind, or everyone’s house, or everyone’s country? No, I don’t think it is. Only Thirst Russell needs to claim that thirst is the only cause of drinking water. If there are other causes, then you can’t infer from water-drinking to sensations of thirst. But aren’t there other causes? Sometimes you need to cleanse your palate, or you’re trying to prevent future thirst, or you’re just absentmindedly drinking because it’s there. Complexity Increases Certainty Russell claims that the more complex the task is, the better the analogical argument is. So if you ask someone to solve a difficult mathematical problem, and they give you the right answer, you are safer in assuming that they did this in the same way as you would. Really? But it would seem that the opposite is true. If I give a difficult problem to 30 different computer programmers, I’m liable to get 30 very different programs written in 30 very different programming languages. Why should we think that there’s not an entirely different set of complicated inner workings– not thoughts or feelings, as for us– in other people? Maybe they have a totally different complex way of operating. Conclusion A lot of philosophers think that the argument from analogy just doesn’t work, because only looking at one instance (how things are for you), is not a good way to generalize about how things are in other instances, for other people. We are justified in believing in other minds, but that justification does not come from an analogical argument. Conclusion The analogy viewpoint also leaves unsolved the conceptual problem of other minds. Here’s what Wittgenstein says: “If one has to imagine someone else’s pain on the model of one’s own, this is none too easy a thing to do: for I have to imagine pain which I do not feel on the model of the pain which I do feel.” CRITERIA Ludwig Wittgenstein (1889-1951) Wittgenstein Ludwig Wittgenstein was the son of the second wealthiest man in the Habsburg Empire, the Austrian steel baron Karl Wittgenstein. His father wanted his sons to be part of his steel empire 3 (out of 5) of them committed suicide, and Ludwig gave away his entire inheritance. Wittgenstein was a student of Russell’s, and many consider him the only philosophical genius of the 20th Century. Philosophical Confusion Wittgenstein thought that the ordinary analogical way we think of other people’s mental states (as being ‘like’ ours) doesn’t make sense. He thought that once you cleared up the confusion about what ‘That other person is in pain’ really means, you would find that obviously, we can know about other people’s minds. Hume Next class when we study the problem of induction, we’ll talk about a famous skeptic, David Hume. But I’ll bring him up now just for some background. Hume thought there wasn’t a problem of other minds, because he thought that there was no evidence that I have a mind. Hume against the ‘Self’ “For my part, when I enter most intimately into what I call myself, I always stumble on some particular impression or other, of heat or cold, light or shade, love or hatred, pain or pleasure. I never can catch myself at any time without a perception, and never can observe anything but the perception.” Denial of Minds What Hume denied was the picture on which there were thinkers and thoughts, or perceivers and perceptions: he argued that there were only thoughts and perceptions, not minds that had those things. His argument was that when you introspected, you found a bunch of thoughts, but you never found you– the thing that does the thinking. Wittgenstein only published one book and one article in his lifetime, so most of what we know about his views is from his notes and other sources. G.E. Moore wrote about lectures Wittgenstein gave in 1930-1933. It Thinks Moore writes, quoting Wittgenstein: ‘Just as no (physical) eye is involved in seeing, no Ego is involved in thinking or in having toothache’; and he quotes, with apparent approval, Lichtenberg’s remark that ‘instead of saying “I think” we ought to say “it thinks”’ The Cogito Again The idea is that Descartes was wrong when he concluded, “I think, therefore I am.” He thought he was certain of a self– himself– a thinker that did the thinking. But you don’t experience yourself, you just experience your thoughts and perceptions. You don’t see your eye when you look out in the world. So the only thing Descartes could really be sure of is not that he exists, but that thoughts were happening. Nothing to Analogize What does this have to do with other minds? If we deny that thinking is a relation between a thinker and a thing thought, but instead maintain that there is just “thinking happening” or “no thinking happening,” then it is impossible to say that I have certain thoughts and experiences and so do other people. There are no selves, so no other minds to do the thinking. Ordinary Language Philosophy Wittgenstein thought that philosophical confusions like this could be resolved by investigating how we use language and what purpose it is put to. He asks why we use mental language like ‘he is in pain’ or ‘he thinks that it will rain later’. If we can figure that out, we’ll know what these assertions really mean. The Role of Mental Talk In Philosophical Investigations, he says: “A child has hurt himself and he cries: and the adults talk to him and teach him new exclamations and, later, sentences. They teach the child new pain-behavior… the verbal expression of pain replaces crying and does not describe it [the pain].” Here, someone saying something like “I am in pain” shows that they are in pain in much the same way that crying does– but it does not describe the state that they are in (crying doesn’t describe your pain, it shows it). And saying ‘he is in pain’ is a lot like saying ‘he is crying’– you are saying that he is engaging in certain pain-behavior. Criterial Connections Wittgenstein’s idea was that certain behavior was criterial for the application of mental talk– that it provided a standard for when to use that talk appropriately. When you learn the language game involving ‘pain’ you learn what behaviors make it appropriate to say that someone else is in pain. And thus saying that they are in pain (correctly) is simply applying ‘pain’ talk when you notice the appropriate behaviors. Behaviorist Solution Therefore, there is no problem of other minds. So long as we are not global skeptics, and we accept that we can know when other people are crying or clutching their sides, or groaning, or saying “I am in pain” then we can know that they are in pain… what it is for them to be in pain is that they exhibit such behaviors. Behaviorism Behaviorism is the idea that mental states are not really “inner” things at all, but rather dispositions to behave in certain ways. To say “Michael believes that Jamaica is a nice vacation spot” is to say something like, “Michael is inclined to buy a ticket to Jamaica when he has free time and disposable income.” Behaviorism The behaviorist has an obvious solution to the problem of other minds: if mental states = behavior, then we can observe people’s mental states by observing their behavior. Old Joke: Two behaviorists meet on the street. “You’re feeling good today,” says one, “how am I feeling?” Objection to Behaviorism The most serious objection to behaviorism is that it can’t be true, because it requires a 1-to-1 connection between behaviors and mental states, when in reality any given mental state can bring about a range of different behaviors, depending on the other mental states involved. Objection to Behaviorism For example, I believe that Jamaica is an excellent vacation spot. Does this mean that I will buy a plane ticket there over winter break? Well, only if I believe that a plane is the best way to get there, and believe that the airline will honor my ticket, and desire to take a vacation, and don’t have a stronger desire to do something else (visit family), etc. Behavior Indirectly Connected with Mental States Your beliefs and desires are only indirectly related to your behavior. Any particular behavior is consistent with your having a large number of different beliefs and desires. Why did you take your umbrella? Because you thought it was raining and you didn’t want to get wet. Or because you thought it was sunny and you didn’t want to get burned. Or because… Or because you thought there were bears outside and they are afraid of umbrellas. Or because you wanted a walking stick, and the umbrella was the best you had. Or because you thought the umbrella was a sandwich and you were hungry… Behavior ≠ Mental States You can never make an identification between behavior B and mental state M: B = M. The reason is that people’s behavior depends on all their beliefs and desires, not just one, M. By changing mental states other than M, and keeping M fixed, you can change the behavior. Summary A denial of the existence of thinkers and perceivers led Wittgenstein to claim that understanding mental states by analogy with our own case made no sense. He proposed an alternative, behaviorist theory on which mental states were identified with certain behaviors. Although behaviorism of this form was popular for a while, most philosophers reject it, because there is no nice correspondence between mental states and behaviors. ABDUCTION The Problem Here’s how I introduced the problem of other minds: we can find out about the physical world and the states of other people’s bodies (behaviors) by perceiving them– looking and touching. We can find out about our own mental states via introspection– “looking inward.” But how can we find out about other minds? Unobservables But there are lots of things that we are justified in believing in which we can neither see nor introspect. For example, I believe in electrons and black holes, even though I can’t see either of them. And the science behind these things really does justify my beliefs– I know that there are electrons and black holes. Abduction One popular solution to the problem of other minds is to view it as an abductive argument: an inference to the best explanation. We observe a complicated range of effects– people’s behavior– and we derive a model which, if it were true, it would explain people’s behavior. Since there is no better model that explains the behavior, we accept this model as true: likely, people do have pains, beliefs, and desires. Example: Neptune Before the discovery of Neptune, in the 19th Century, measurements of the orbit of Uranus showed that it did not behave in the way that it should, if there are no other planets in the solar system. Astronomers then inferred that the best explanation for its irregular orbit was that there was another undiscovered, unobserved planet. Later, the planet was observed, and we call it ‘Neptune.’ Reverse Engineering In general, abduction reasons from the effects to their most likely causes. It is like “reverse engineering.” For example, if you want to find out how a particular piece of software works, you give it various inputs and see how it behaves– does it take a long time to return answers to certain problems or does it crash? Observing its behavior allows you to infer the hidden structure of its program. Reverse Engineering the Mind In the case of other people’s minds, we observe inputs (what is in people’s line of sight, what’s in range of hearing, what’s in their mouth…) and we observe outputs– how they behave, what they say. We then infer the hidden, internal processes that mediate between input and output: beliefs, desires, emotions, and so on. Computational Theory of Mind In fact, if the computational theory of mind is correct, then inferring the mental states of other people is the exact same thing as reverse engineering a piece of software. According to CTM, the mind is the software of the brain. So observing the inputs and outputs of that software allows us to infer the nature of the software itself: the beliefs and desires of other individuals. Comparison with Analogy This strategy is different from the argument from analogy. There, it was important to find out how our own minds worked, and then to reason that other people must be like us. The abductive inference strategy looks at observable inputs and outputs for lots of other people. We aren’t just restricted to our own case. Comparison with Behaviorism It is different from Behaviorism too. The behaviorist wanted to identify mental states with people’s outputs: their behavior. On the abductive inference strategy, behavior is different fromthe hidden, internal mental states, but it is evidence regarding what those states are like. Prediction But how exactly are beliefs and desires supposed to explain the behavior of other people? Consider this case. I call a friend in the U.S. and ask him to give a guest lecture two weeks from now in class. She says yes, she’d love to. Where will she be two weeks from now? Prediction All our sophisticated knowledge of brain science won’t allow us to make a good prediction here. We could scan her brain with PET scans and fMRI’s for days, record her individual neurons with invasive electrodes, and measure every aspect of her physiology… but still, that wouldn’t come close to a reasonable prediction of where she’ll be in two weeks. But we know the answer… she’ll be here! The Abductive Argument 1. My friend says “I will come teach class at HKU two weeks from now. 2. The best explanation for this is that she intends to fly to HKU and teach class (she’s not lying). 3. People generally do what they intend to do. 4. Therefore she will fly to HKU and be in class in two weeks. Confirmed by Experience The fact that such prediction is so often successful, and so much superior to all of our other sophisticated science, is good reason to believe that the theoretical entity it posits– my friends intention– and the causal relations it assumes that entity to enter into– intentions to do X cause people to do X– are real. Mind Reading There is evidence that the way we actually go about attributing mental states to other people and explaining and predicting their behavior involves these sorts of abductive inferences. Three-year old children and people who are high on the autism spectrum have trouble attributing beliefs to other people, and so have trouble making accurate predictions about others. The Sally-Ann Task http://www.youtube.com/watch?v=EUG24VRjp 7c Young children know where the cookie is (in the box), so they assume other people know where it is. They don’t have the idea that other people can have beliefs that differ from their own. Mind Reading As we mature, we become more adept at positing distinct arrays of beliefs and desires in other people, and use those models in a predictive and explanatory way. This is proof that evolution itself has seen fit to adopt the “theoretical entities” approach to mental states, and treat them as unobserved causes of others’ behaviors. Objections There are three objections to the abductive strategy: First, the theory is circular: it needs to assume its own truth to prove that it’s true. Second, we have addressed the epistemological, but not the conceptual, problem of other minds. Third, we still have no reason to suppose that other people have conscious inner lives. Circularity? Hyslop (SEP) argues that the functionalist solution to the problem of other minds is circular: functionalism is a theory about how everyone’s mind works. To establish that theory, you have to have lots of knowledge about minds– yours and other people’s– so you have to solve the problem of other minds before you can use functionalism to solve the problem of other minds. Missing the Point I think this misses the point of the abductive strategy. Here, we do assume in advance that functionalism is true, and see what that predicts. But then we go out looking and we find that our predictions have come true. So we conclude that functionalism must be true, because no other theory better explains the data. The Conceptual Problem The conceptual problem of other minds is that we cannot even have an idea of someone else having a mind, because we can neither see their mental states, nor introspect them, and those are the only ways we have of conceptually grasping other things. Easy Response In this simple form, I think the abductive strategy/ functionalism has an easy response. We can have ideas of things we don’t see or introspect, like electrons, black holes, and even Neptune (at one point in history). The model of concepts proposed by the “conceptual problem” is deficient. Wittgenstein’s Conceptual Problem However, I think there is a more difficult problem if the considerations urged by Wittgenstein are correct. If there really are no thinkers, but only thoughts, how do I think of a thought that is not thought by me, but by someone else? Thoughts aren’t thought by anyone! Response to Wittgenstein I think we can respond to the challenge though: Wittgenstein says there is no eye in the field of vision. We see things, we don’t see an eye seeing things. Similarly, there is no thinker in what is thought. When I introspect, I see thoughts, but there is no thinker there among the thoughts. Response to Wittgenstein But this is no reason to deny that eyes exist. You see the outside world, not an eye seeing the outside world. But you do it with your eyes. They still exist, even if they’re not what you see. Similarly, thinkers exist. The reason Hume doesn’t see himself among his thoughts is that his self is not a thought, it’s the thing having them. This is no reason to think it doesn’t exist. Philosophical Zombies Again The big problem, as I see it, with the abductive strategy/ functionalism is that it doesn’t give us any reason to suppose that other people have conscious inner lives. If CTM is true, other people are computers that run sophisticated programs. But computers aren’t all conscious, or so we think. What reason do we have to think those computers are conscious? SUMMARY The Problem of Other Minds The epistemological problem of other minds is a variety of local skepticism. It’s the worry that we can’t have knowledge about other minds because we don’t ever perceive or experience the thoughts of others. Three Solutions We considered three potential solutions: 1. Analogy: we can know about other minds by analogy with our own mind. 2. Behaviorism: we can know about other minds because mental states = behavior, and we can observe behavior. 3. Abduction: we can know about other minds the way we know about other unobserved entities: inference to the best explanation. Analogy The main objection to the argument from analogy was that it relied on too few instances (only one). Just because I know how something is in my mind/ at my house/ in my country, doesn’t mean I know how it is in every mind/ at every house/ at every country. Behaviorism The main objection to behaviorism was that, while it provided a nice solution to the problem, it was implausible to believe that mental states were just dispositions to behave in certain ways. One and the same belief could cause any behavior you can imagine, given enough other, different mental states. Abduction It’s quite plausible that the way we know about other people’s beliefs and desires is by inferring them as the most reasonable explanation for their behavior. However, even if we accept this story, we still have no account of how we know that other people have conscious inner lives.