EPISTEMOLOGIST: Fortunately, the correctness of your claim can be experimentally decided. It so happens that I now have two brain-reading machines in my office, so I now direct one to your brain to find out what you mean by belief and the other to my own brain to find out what I mean by belief, and I shall compare the two readings. Nope, I’m sorry, but it turns out that we mean exactly the same thing by the word belief.
FRANK: Oh, hang your machine! Do you believe we mean the same thing by the word belief?
EPISTEMOLOGIST: Do I believe it? Just a moment while I check with the machine. Yes, it turns out that I do believe it.
FRANK: My goodness, do you mean to say that you can’t even tell me what you believe without consulting the machine?
EPISTEMOLOGIST: Of course not.
RANK: But most people when asked what they believe simply tell you. Why do you, to find out your beliefs, go through the fantastically roundabout process of directing a brain-reading machine to your own brain and then finding out what you believe on the basis of the machine’s readings?
EPISTEMOLOGIST: What other scientific, objective way is there of finding out what I believe?
FRANK: Oh come now, why don’t you just ask yourself?
EPISTEMOLOGIST (sadly): It doesn’t work. Whenever I ask myself what I believe, I never get any answer!
FRANK: Well, why don’t you just state what you believe?
EPISTEMOLOGIST: How can I state what I believe before I know what I believe?
FRANK: Oh, to hell with your knowledge of what you believe; surely you have some idea or belief as to what you believe, don’t you?
EPISTEMOLOGIST: Of course I have such a belief. But how do I find out what this belief is?
FRANK: I am afraid we are getting into another infinite regression. Look, at this point I am honestly beginning to wonder whether you may be going crazy.
EPISTEMOLOCIST: Let me consult the machine. Yes, it turns out that I may be going crazy.
FRANK: Good God, man, doesn’t this frighten you?
EPISTEMOLOGIST: Let me check! Yes, it turns out that it does frighten me.
FRANK: Oh please, can’t you forget this damned machine and just tell me whether you are frightened or not?
EPISTEMOLOGIST : I just told you that I am. However, I only learned of this from the machine.
FRANK: I can see that it is utterly hopeless to wean you away from the machine. Very well, then, let us play along with the machine some more. Why don’t you ask the machine whether your sanity can be saved?
EPISTEMOLOGIST: Good idea! Yes, it turns out that it can be saved.
FRANK: And how can it be saved?
EPISTEMOLOGIST: I don’t know, I haven’t asked the machine.
FRANK: Well, for God’s sake, ask it!
EPISTEMOLOGIST: Good idea. It turns out that …
FRANK: It turns out what?
EPISTEMOLOGIST: It turns out that …
FRANK: Come on now, it turns out what?
EPISTEMOLOGIST: This is the most fantastic thing I have ever come across! According to the machine, the best thing I can do is to cease to trust the machine!
FRANK: Good! What will you do about it?
EPISTEMOLOGIST: How do I know what I will do about it; I can’t read the future!
FRANK: I mean, What do you presently intend to do about it?
EPISTEMOLOGIST: Good question, let me consult the machine. According to the machine, my present intentions are in complete conflict. And I can see why! I am caught in a terrible paradox! If the machine is trustworthy, then I had better accept its suggestion to distrust it. But if I distrust it, then I must also distrust its suggestion to distrust it, so I am really in a total quandary.
FRANK: Look, I know someone who I think might really be of help in this problem. I shall leave you for a while to consult him. Until then, au revoir!
Scene 4 (later in the day at a psychiatrist’s office).
FRANK: Doctor, I am terribly worried about a friend of mine. He calls himself an experimental epistemologist.
DOCTOR: Oh, the experimental epistemologist. There is only one in the world. I know him well!
FRANK: That is a relief. But do you realize that he has constructed a brain-reading device that he now directs to his own brain, and whenever one asks him what he thinks, believes, feels, fears, and so forth, he has to first consult the machine before answering? Don’t you think this is pretty serious?
DOCTOR: Not as serious as it might seem. My prognosis for him is actually quite good.
FRANK: Well, if you are a friend of his, couldn’t you sort of keep an eye on him?
DOCTOR: I do see him quite frequently, and I do observe him, but I don’t think that he can be helped by so-called psychiatric treatment. His problem is an unusual one and is the sort that has to work itself out. And I believe it will.
FRANK: Well, I hope your optimism is justified. At any rate, I sure think that I need some help at this point!
DOCTOR: How so?
FRANK: My experiences with the epistemologist have been thoroughly unnerving! At this point, I wonder if I may be going crazy; I can’t even have confidence in how things appears to me. I think maybe you could be helpful here.
DOCTOR: I would be happy to help but cannot for awhile. For the next three months, I am unbelievably overloaded with work. After that, I unfortunately must go on a three-month vacation. So in six months, come back and we can talk this over.
Scene 5 (same office, six months later).
DOCTOR: Before we go into your problems, you will be happy to hear that your friend the epistemologist is now completely recovered.
FRANK: Marvelous! How did it happen?
DOCTOR: Almost, as it were, by a stroke of fate—and yet his very mental activities were, so to speak, part of the “fate.” What happened was this. For months after you last saw him, he went around worrying, Should he trust the machine, shouldn’t he trust the machine, should he, shouldn’t he, should he, shouldn’t he? (He decided to use the word should in your empirical sense.) He got nowhere! So he then decided to formalize the whole argument. He reviewed his study of symbolic logic, took the axioms of first order logic, and added as nonlogical axioms certain relevant facts about the machine. Of course, the resulting system was inconsistent—he formally proved that he should trust the machine if and only if he shouldn’t and hence that he both should and should not trust the machine. Now, as you may know, in a system based on classical logic (which is the logic he used), if one can prove so much as a single contradictory proposition, then one can prove any proposition, hence the whole system breaks down. So he decided to use a logic close to what is known as minimal logic that is weaker than classical logic. In this weaker logic the proof of one contradiction does not necessarily entail the proof of every proposition. However, this system turned out to be too weak to decide the question of whether or not he should trust the machine. Then he had the following bright idea. Why not use classical logic in his system even though the resulting system is inconsistent? Is an inconsistent system necessarily useless? Not at all! Even though, given any proposition, there exists a proof that it is true and another proof that it is false, it may be the case that for any such pair of proofs, one of them is simply more psychologically convincing than the other, so simply pick the proof that you actually believe! Theoretically, the idea turned out very well—the actual system he obtained really did have the property that, given any such pair of proofs, one of them was always psychologically far more convincing than the other. Better yet, given any pair of contradictory propositions, all proofs of one were more convincing than any proof of the other. Indeed, anyone except the epistemologist could have used the system to decide whether the machine could be trusted. But the epistemologist obtained one proof that he should trust the machine, and another proof that he should not. Which proof was more convincing to him, which proof did he really believe? The only way that he could find out was to consult the machine! But he realized that this would be beggi
ng the question, since his consulting the machine would be a tacit admission that he did in fact trust the machine. So he still remained in a quandary.
FRANK: So how did he get out of it?
DOCTOR: Here is where fate kindly interceded. Because of his absolute absorption in the theory of this problem, which consumed almost all his waking hours, he became for the first time in his life experimentally negligent. As a result, a few minor units of his machine blew out without his knowing! Then, for the first time, the machine started giving contradictory information—not merely subtle paradoxes but blatant contradictions. In particular, the machine claimed one day that the epistemologist believed a certain proposition, and a few days later claimed that he did not believe that proposition. To add insult to injury, the machine claimed that he had not changed his belief in the last few days. This was enough to make him totally distrust the machine. Now he is fit as a fiddle.
FRANK: This is certainly the most amazing thing I have ever heard! I guess the machine was really dangerous and unreliable all along.
DOCTOR: Oh, not at all; the machine used to be excellent before the epistemologist’s experimental carelessness put it out of whack.
FRANK: Welt, surely when I knew it, it couldn’t have been very reliable.
DOCTOR: Not so, Frank, and this brings us to your problem. I know about your entire conversation with the epistemologist. It was all tape-recorded.
FRANK: Then surely you realize that the machine could not have been right when it denied that I believed the book was red.
DOCTOR: Why not?
FRANK: Good God, do I have to go through all this nightmare again? I can understand that a person can be wrong if he claims that a certain physical object has a certain property, but have you ever known a single case in which a person can be mistaken when he claims to have or not have a certain sensation?
DOCTOR: Why, certainly! I once knew a Christian Scientist who had a raging toothache; he was frantically groaning and moaning all over the place. When asked whether a dentist might not cure him, he replied that there was nothing to be cured. Then he was asked, “But do you not feel pain?” He replied, “No, I do not feel pain; nobody feels pain, there is no such thing as pain, pain is only an illusion.” So here is a case of a man who claimed not to feel pain, yet everyone present knew perfectly well that he did feel pain. I certainly don’t believe that he was lying; he was simply mistaken.
FRANK: Well, all right in a case like that. But how can one be mistaken if one asserts his belief about the color of a book?
DOCTOR: I can assure you that, without access to any machine, if I asked someone the color of a book and he answered, “I believe that it is red,” I would be very doubtful that he really believed it. It seems to me that if he really believed it, he would answer, “It is red,” and not, “I believe that it is red,” or, “It seems red to me.” The very timidity of his response would be indicative of his doubts.
FRANK: But why on earth should I have doubted that it was red?
DOCTOR: You should know that better than I. Let us see now, have you ever in the past had reason to doubt the accuracy of your sense perception?
FRANK: Why, yes. A few weeks before visiting the epistemologist, I suffered from an eye disease, which did make me see colors falsely. But I was cured before my visit.
DOCTOR: Oh, so no wonder you doubted that it was red! True enough, your eyes perceived the correct color of the book, but your earlier experience lingered in your mind and made it impossible for you to really believe that it was red. So the machine was right!
FRANK: Well, all right, but then why did I doubt that I believed it was red?
DOCTOR: Because you didn’t believe that it was red, and you were unconsciously smart enough to realize that. Besides, when one starts doubting one’s own sense perceptions, the doubt spreads like an infection to higher and higher levels of abstraction until finally the whole belief system becomes one doubting mass of insecurity. I bet that if you went now to the epistemologist’s office, and if the machine were repaired, and you now claimed that you believe the book is red, the machine would concur.
No, Frank, the machine is—or rather was—a good one. The epistemologist learned much from it but misused it when he applied it to his own brain. He really should have known better than to create such an unstable situation. The combination of his brain and the machine each scrutinizing and influencing the behavior of the other led to serious problems in feedback. Finally, the whole system went into a cybernetic wobble. Something was bound to give sooner or later. Fortunately, it was the machine.
FRANK: I see. One last question, though. How could the machine be trustworthy when it claimed to be untrustworthy?
DOCTOR: The machine never claimed to be untrustworthy, it only claimed that the epistemologist would be better off not trusting it. And the machine was right.
7
A Mind-Body Fantasy
In Rudolf Carnap’s article “Psychology in Physical Language,” he argues that every sentence of psychology may be formulated in physical language.1 As he expresses it, all sentences of psychology describe physical occurrences, namely, the physical behavior of humans and other animals.
I do not see that the second formulation is really implied by the first. It may indeed be perfectly possible that every statement in psychology may be translatable into a statement in physics. But this does not mean that statements in psychology arc about physical occurrences. The following analogy will, I hope, add some insight into this point.
Imagine (if you can!) a world with the very curious property that any two objects have the same color if and only if they happen to have the same shape. So, for instance, all red objects are spherical and all spherical objects red; all green objects are cubical and all cubical objects green; and so forth. Imagine also that half the inhabitants of the world are completely color-blind, and the other half see colors perfectly. In this world, color is the analogue of mental and shape is the analogue of Physical. Hence, the materialists are the color-blind, and the dualists are the color-sighted. (Unfortunately, I cannot fit pure idealists into this world, for who could they be other than people who could see colors but not shapes—and this is too outlandish even for me!)
Imagine the metaphysical controversies that might rage on such a planet! The color-sighted people would claim certainty that objects could differ not only in size and shape but also by something else equally important, which they called color; they would claim to know this by direct perception and not through any process of reasoning! The color-blind people would be completely skeptical; they would consider the views of the color-sighted occult or mystical, and with good reason! In this setup, the color-sighted people would have absolutely no way of demonstrating their color-vision to the color-blind! Whenever a color-sighted person could distinguish two objects by their color-difference, a color-blind person could just as well distinguish them by their difference in shape. So no empirical demonstration to the color-blind would be possible. Also, in this setup, all statements about colors would be translatable into statements about shapes (at least in the opinion of the color-blind! Now suppose that the color-sighted developed a dual vocabulary employing both color-words and shape-words. (I will consider some objections to this dual vocabulary later.) Half the words of this vocabulary would be redundant to the color-blind. A color-sighted person would say, “This object is both spherical and red, which is saying two very different things about it.” The color-blind person would reply, “I still cannot understand your distinction between the words spherical and red.” Imagine the theories that the color-sighted people might invent to account for the dual phenomena of shape and color! Some might regard shape and color as different aspects or modes of the same underlying substance. Others might marvel that God has preordained some miraculous harmony between shapes and colors. Then there would arise an identity theory that would maintain that despite the possible difference between the meanings of the words color and shape, colors and shapes t
hemselves were nevertheless the same things. Of course, the color-blind people would have no idea what the metaphysicians were talking about.
Naturally, one can easily pick my analogy to pieces. For one thing, it could be asked, “What happens if a red sphere is cut into two hemispheres; do the two halves suddenly change color?” Of course they would have to in such a world! How? By some weird physical law or other. Also, in such a world, there could be no two sources of different monochromatic lights—let’s say there was only a constant source of white light. Many other utter implausibilities would have to be explained, but the point is not whether such a world is remotely realistic or even logically possible; this is only an analogy whose purpose is (I hope) to provide some feeling for certain aspects of the mind-body problem.
There are, however, even more fundamentally serious difficulties with this analogy. In the first place, why should the color-sighted have ever developed a dual vocabulary? Next, how could the color-sighted have ever known that the others were color-blind? For that matter, how could a color-sighted person test someone else to find out whether or not he had color-vision? And for that matter, could anyone know whether he could see colors or not? In fact, could any distinction at all between colors and shapes ever have arisen; could these two different notions have developed?
I think that this question is highly important, but I do not claim to know the answer. I suspect that the answer is, “Yes, they would,” but, curiously enough, by analogy with the mind-body problem. Let us for the moment assume there is a perfect parallelism between mental and physical events. Nevertheless, some people on this earth —perhaps the majority—do indeed make a radical distinction between the two and strongly claim that these are two very different notions, not one.
Five Thousand B.C. and Other Philosophical Fantasies Page 7