ACHILLES: I? Which one would be me?
TORTOISE: Any of them: all of them; or perhaps, none of them.
ACHILLES: This is eerie. I don’t know where I would be—if anywhere. And all of those weird catalogues would be claiming to be me.
TORTOISE: Well, you should expect as much: you do it yourself, don’t you? Why, I could even introduce a pair of you—or all of you—to each other.
ACHILLES: Uh-oh. I was waiting for this moment. Every time I see you, you spring something like this on me.
TORTOISE: There just might ensue a teeny scrap over which one was the real one, don’t you think so?
ACHILLES: Oh, this is a diabolical scheme to squeeze the juice out of the human soul. I’m losing a clear sight of who “I” is. Is “I” a person? A process? A structure in my brain? Or is “I” some uncapturable essence that feels what goes on in my brain?
ACHILLES: An interesting question. Let us go back to Einstein, to examine it. Did Einstein die, or was he kept on living by the creation of the catalogue?
ACHILLES: Well, to all appearances, some part of his spirit was kept alive by the fact that the data were recorded.
TORTOISE: Even if the book never was used? Would he be alive then?
ACHILLES: Oh, that’s a difficult one. I guess I’d have to say “no.” Clearly what made him live on was the fact that we “brought him to life” from out of the sterile book, “a bit at a time.” It was the process, above and beyond the mere data book. He was conversing with us, that’s what made him alive. His neurons were firing, in a somewhat figurative way, albeit rather slowly compared to their usual speed—but that’s of no consequence, as long as they were firing.
TORTOISE: Supposing it took you ten seconds to do round one, a hundred seconds to do round two, a thousand seconds to accomplish round three, and so forth. Of course, the book would not know how long all this took, because its only contact with the outside world is through its auditory conversion tables—and in particular, it can never know anything that you don’t choose to tell it. Would it still be as alive, despite the enormous sluggishness of its firing after a few rounds?
ACHILLES: I don’t see why not. If I too had been catalogued in the same way and my pages were being flipped equally lethargically, our rates of conversation would be matched. Neither he nor I would have cause to feel any abnormality in the conversation, even if, in the outer world, our mere exchange of greetings lasted millennia.
TORTOISE: You at first spoke of this process that brings out the structure “a bit at a time” as being so important, yet now it seems it doesn’t matter if it’s constantly slowing down. Eventually the rate of exchange of thoughts would be a syllable a century. And after a while, one neuron would fire every trillion years. Not exactly a sparkling conversation!
ACHILLES: Not in the outer world, no. But to the two of us, who are unaware of the passage of time in the outer world, all is well and normal, as long as someone does our internal bookwork—no matter how slowly. Einstein and I are serenely oblivious to the fast-changing world outside our flipping pages.
TORTOISE: Suppose this faithful neural clerk—let’s call him A-kill-ease, just for fun (no relation to present company, of course)—just suppose he slipped off one afternoon for a little nip, and forgot to come back....
ACHILLES: Foul play! Double homicide! Or do I mean bibliocide?
TORTOISE: Is it all that bad? Both of you are still there, “all at once.”
ACHILLES: “All at once,” bah! What’s the fun of life if we’re not being processed?
TORTOISE: Was it any better at an ever-slowing snail’s pace?
ACHILLES: At any pace, it’s better. Even a Tortoise’s. But say—what’s the point of calling the book-tender “A-kill-ease”?
TORTOISE: I just thought I’d let you think about how it would feel if your brain were not only encoded in a book, but also you were minding that very brain-book (no pun intended, to be sure!).
ACHILLES: I suppose I would have to ask my own book. Or no—wait a minute. My book would have to ask me! Oh, I’m so befuddled by these confounded and compounded level-confusions you always hit me with out of the blue! Ah! I have a grand idea. Suppose there was a machine that came along with the books, a machine that does the page turning, the little calculations, and the clerical work. This way we would avoid the problem of human unreliability, as well as your strange twisty loop.
TORTOISE: Suppose so—an ingenious plan. And suppose the machine broke.
ACHILLES: Oh, you have a morbid imagination! What recherché tortures you would put me through!
TORTOISE: Not at all. Unless somebody told you of it, you wouldn’t even be aware of the machine’s existence, much less that the machine had broken.
ACHILLES: I don’t like this isolation from the outer world. I’d rather have some way of sensing what’s going on around me than be dependent upon people telling me things of their own choice. Why not take advantage of the neurons which, in life, processed visual input? Just like the auditory conversion tables, we could have optical conversion tables. These will be used to create changes in the book according to the signals from a television camera. Then I could watch the world about me, and react to its events. In particular, I’d soon become aware of the page-turning machine, the book full of so many pages and numbers, and so on....
TORTOISE: Oh, you are determined to suffer. So now you’ll perceive the fate that is to befall you: You’ll “see,” by means of input fed into you via the television camera and the conversion tables, that the mechanical page-turner that has served you so well has a loose part that is just about to slip. That’ll scare you, all right. And what good is that? If you had no optical scanning device, you’d have no way of knowing what’s going on in the world about you, not even with respect to your page-turner. Your thoughts proceed calmly and coolly, unaffected by the cares of the outside world, blithely unaware that they may soon come to a forced end, since the page-turner may break. An idyllic existence! Up until the very end, not a worry!
ACHILLES: But when it breaks, I would be dead and gone.
TORTOISE: You would?
ACHILLES: I’d be a lifeless, motionless heap of number-covered sheets.
TORTOISE: A pity, I’m sure. But maybe old A-kill-ease would somehow find his way back to his familiar haunts, and take up where the broken machine left off.
ACHILLES: Oh! So I’d be resuscitated. I was dead for a while, and then returned to life!
TORTOISE: If you insist on making these strange distinctions. What makes you any “deader” when the machine breaks than you are when A-kill-ease leaves you unattended for a few minutes or a few years, to play a game of backgammon, to take a trip around the world, or to go get his brain copied into a book?