It is interesting to think about two systems that are so alike that they have isomorphic, or identical, self-symbols—say a woman and an atom-by-atom replica of her. If she thinks about herself, is she also thinking about her replica? Many people fantasize that somewhere out there in the heavens, there is another person just like them. When you think about yourself, are you also thinking, without being aware of it, about that person? Who is that person thinking about right now? What would it be like to be that person? Are you that person? If you had a choice, would you let that person be killed, or yourself?
The one thing that Nagel seems not to have acknowledged in his article is that language (among other things) is a bridge that allows us to cross over into territory that is not ours. Bats don’t have any idea of “what it is like to be another bat” and don’t wonder about it, either. And that is because bats do not have a universal currency for the exchange of ideas, which is what language, movies, music, gestures, and so on give us. These media aid in our projection, aid us in absorbing foreign points of view. Through a universal currency, points of view become more modular, more transferable, less personal and idiosyncratic.
Knowledge is a curious blend of objective and subjective. Verbalizable knowledge can be passed around and shared, to the extent that words really “mean the same thing” to different people. Do two people ever speak the same language? What we mean by “speak the same language” is a prickly issue. We accept and take for granted that the hidden subterranean flavors are not shared. We know what comes with and what is left out of linguistic transactions, more or less. Language is a public medium for the exchange of the most private experiences. Each word is surrounded, in each mind, by a rich and inimitable cluster of concepts, and we know that no matter how much we try to bring to the surface, we always miss something. All we can do is approximate. (See George Steiner’s After Babel for an extended discussion of this idea.)
By means of meme-exchange media (see selection 10, “Selfish Genes and Selfish Memes”) such as language and gestures, we can experience (vicariously sometimes) what it is like to be or do X. It’s never genuine, but then what is genuine knowledge of what it is like to be X? We don’t even quite know what it was like to be ourselves ten years ago. Only by rereading diaries can we tell—and then, only by projection! It is still vicarious. Worse yet, we often don’t even know how we could possibly have done what we did yesterday. And, when you come right down to it, it’s not so clear just what it is like to be me, right now.
Language is what gets us into this problem (by allowing us to see the question) and what helps to get us out as well (by being a universal thought-exchange medium, allowing experiences to become sharable and more objective). However, it can’t pull us all the way.
In a sense, Gödel’s Theorem is a mathematical analogue of the fact that I cannot understand what it is like not to like chocolate, or to be a bat, except by an infinite sequence of ever-more-accurate simulation processes that converge toward, but never reach, emulation. I am trapped inside myself and therefore can’t see how other systems are. Gödel’s Theorem follows from a consequence of that general fact: I am trapped inside myself and therefore can’t see how other systems see me. Thus the objectivity-subjectivity dilemmas that Nagel has sharply posed are somehow related to epistemological problems in both mathematical logic, and as we saw earlier, the foundations of physics. These ideas are developed in more detail in the last chapter of Gödel, Escher, Bach by Hofstadter.
D.R.H.
Scene 1. Frank is in the office of an eye doctor. The doctor holds up a book and asks “What color is it?” Frank answers, “Red.” The doctor says, “Aha, just as I thought! Your whole color mechanism has gone out of kilter. But fortunately your condition is curable, and I will have you in perfect shape in a couple of weeks.”
Scene 2. (A few weeks later.) Frank is in a laboratory in the home of an experimental epistemologist. (You will soon find out what that means!) The epistemologist holds up a book and also asks, “What color is this book?” Now, Frank has been earlier dismissed by the eye doctor as “cured.” However, he is now of a very analytical and cautious temperament, and will not make any statement that can possibly be refuted. So Frank answers, “It seems red to me.”
EPISTEMOLOGIST: Wrong!
FRANK: I don’t think you heard what I said. I merely said that it seems red to me.
EPISTEMOLOGIST: I heard you, and you were wrong.
FRANK: Let me get this clear; did you mean that I was wrong that this book is red, or that I was wrong that it seems red to me?
EPISTEMOLOGIST: I obviously couldn’t have meant that you were wrong in that it is red, since you did not say that it is red. All you said was that it seems red to you, and it is this statement which is wrong.
FRANK: But you can’t say that the statement “It seems red to me” is wrong.
EPISTEMOLOGIST: If I can’t say it, how come I did?
FRANK: I mean you can’t mean it.
EPISTEMOLOGIST: Why not?
FRANK: But surely I know what color the book seems to me!
EPISTEMOLOGIST: Again you are wrong.
FRANK: But nobody knows better than I how things seem to me.
EPISTEMOLOGIST: I am sorry, but again you are wrong.
FRANK: But who knows better than I?
EPISTEMOLOGIST: I do.
FRANK: But how could you have access to my private mental states?
EPISTEMOLOGIST: Private mental states! Metaphysical hogwash! Look, I am a practical epistemologist. Metaphysical problems about “mind” versus “matter” arise only from epistemological confusions. Epistemology is the true foundation of philosophy. But the trouble with all past epistemologists is that they have been using wholly theoretical methods, and much of their discussion degenerates into mere word games. While other epistemologists have been solemnly arguing such questions as whether a man can be wrong when he asserts that he believes such and such, I have discovered how to settle such questions experimentally.
FRANK: How could you possibly decide such things empirically?
EPISTEMOLOGIST: By reading a person’s thoughts directly.
FRANK: You mean you are telepathic?
EPISTEMOLOGIST: Of course not. I simply did the one obvious thing which should be done, viz. I have constructed a brain-reading machine—known technically as a cerebrescope—that is operative right now in this room and is scanning every nerve cell in your brain. I thus can read your every sensation and thought, and it is a simple objective truth that this book does not seem red to you.
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