I Am a Strange Loop

CHAPTER 21

A Brief Brush with Cartesian Egos

Well-told Stories Pluck Powerful Chords

IN THE preceding dialogue, the query most insistently posed by Strange Loop #642 was, “What makes me housed in this particular brain, rather than in any other one?” However, even though Strange Loop #641 tried to provide an answer to this enigma in several different fashions, Strange Loop #642 always had the nagging feeling that Strange Loop #641 hadn’t really gotten the question, and hadn’t understood how profoundly central it is to human existence. Could it be that there is a fundamental breach of communication here, and that some people simply never will get the question because it is too subtle and elusive?

Well, if one is not averse to using a science-fiction scenario, this same question can be posed so vividly and starkly that hopefully no one could fail to understand and feel deeply troubled by the enigma. One way of doing this appears in the path-breaking book Reasons and Persons by the Oxford philosopher Derek Parfit. Here is how Parfit poses the riddle:

I enter the Teletransporter. I have been to Mars before, but only by the old method, a space-ship journey taking several weeks. This machine will send me at the speed of light. I merely have to press the green button. Like others, I am nervous. Will it work? I remind myself what I have been told to expect. When I press the button, I shall lose consciousness, and then wake up at what seems a moment later. In fact I shall have been unconscious for about an hour. The Scanner here on Earth will destroy my brain and body, while recording the exact states of all my cells. It will then transmit this information by radio. Travelling at the speed of light, the message will take three minutes to reach the Replicator on Mars. This will then create, out of new matter, a brain and body exactly like mine. It will be in this body that I shall wake up.

Though I believe that this is what will happen, I still hesitate. But then I remember seeing my wife grin when, at breakfast today, I revealed my nervousness. As she reminded me, she has been often teletransported, and there is nothing wrong with her. I press the button. As predicted, I lose and seem at once to regain consciousness, but in a different cubicle. Examining my new body, I find no change at all. Even the cut on my upper lip, from this morning’s shave, is still there.

Several years pass, during which I am often Teletransported. I am now back in the cubicle, ready for another trip to Mars. But this time, when I press the green button, I do not lose consciousness. There is a whirring sound, then silence. I leave the cubicle, and say to the attendant, “It’s not working. What did I do wrong?”

“It’s working,” he replies, handing me a printed card. This reads: “The New Scanner records your blueprint without destroying your brain and body. We hope that you will welcome the opportunities which this technical advance offers.”

The attendant tells me that I am one of the first people to use the New Scanner. He adds that, if I stay an hour, I can use the Intercom to see and talk to myself on Mars.

“Wait a minute,” I reply, “If I’m here I can’t also be on Mars.”

Someone politely coughs, a white-coated man who asks to speak to me in private. We go to his office, where he tells me to sit down, and pauses. Then he says: “I’m afraid that we’re having problems with the New Scanner. It records your blueprint just as accurately, as you will see when you talk to yourself on Mars. But it seems to be damaging the cardiac systems which it scans. Judging from the results so far, though you will be quite healthy on Mars, here on Earth you must expect cardiac failure within the next few days.”

The attendant later calls me to the Intercom. On the screen I see myself just as I do in the mirror every morning. But there are two differences. On the screen I am not left–right reversed. And, while I stand here speechless, I can see and hear myself, in the studio on Mars, starting to speak.

Since my Replica knows that I am about to die, he tries to console me with the same thoughts with which I recently tried to console a dying friend. It is sad to learn, on the receiving end, how unconsoling these thoughts are. My Replica assures me that he will take up my life where I leave off. He loves my wife, and together they will care for my children. And he will finish the book that I am writing. Besides having all of my drafts, he has all of my intentions. I must admit that he can finish my book as well as I could. All these facts console me a little. Dying when I know that I shall have a Replica is not quite as bad as simply dying. Even so, I shall soon lose consciousness, forever.

What Pushovers We Are!

The concerns around which Parfit’s two-part story revolves are clearly those that haunted Strange Loop #642. In the first part, we worry along with Parfit whether he will truly exist again after he is atomized on Earth and the signals carrying his ultra-detailed blueprint have reached Mars and directed the construction of a new body; we fear that the newly built person will merely be someone who looks precisely like and thinks precisely like Parfit, but is not Parfit. Soon, however, we are relieved to find out that our worries are unfounded: Parfit himself made it, down to the last tiny scratch. Great! And how do we know that he did? Because he told us so! But which “he” is it that gives us this good news? Is this Derek Parfit the philosopher–author, or is it Derek Parfit the intrepid space voyager?

It is Parfit the space voyager. As it happens, Parfit the philosopher is just spinning a good yarn, doing his best to make it sound teddibly realistic, but we soon find out that, in fact, he doesn’t believe in several parts of his own story. The second episode in his fantasy starts out by contradicting the first one. When we find out that the New Scanner, in contrast to the old one, doesn’t destroy the “original”, we go right along with the tacit idea that Parfit the intrepid space voyager has not voyaged anywhere. We don’t question his stepping out of the cubicle on Earth, because he’s still here.

Oh, but what mindless pushovers we are! Whereas we bought right into the “teleportation equals travel” theme of Episode I, falling for it hook, line, and sinker, we seem in Episode II to have unthinkingly taken the path of least resistance, which runs something like this: “If there are two different things that look like, think like, and quack like Derek Parfit, and if one of those things is located where we last saw Parfit and the other one of them is farther away, then, by God, the close one is obviously the real one, and the far one is just a copy — a clone, a counterfeit, an impostor, a fake.”

This already is plenty of food for thought. If the copy on Mars is a fake in Episode II, why wasn’t it a fake in Episode I? Why were we such suckers when we read Episode I? We naïvely bought into his wife’s reassuring smile at breakfast, and then, when he stepped out of the Martian cubicle, that telltale nick on his face convinced us beyond all doubt. We took his word for it that it was indeed he who was stepping out of the cubicle. But what else could we have expected? Was the newborn body going to step out of the cubicle and proclaim, “Oh, horrors, I’m not me! I’m someone else who merely looks like me, and who has all of my memories stretching all the way back to childhood, and even my memory of breakfast only a few moments ago with my wife! I’m just a sham, but oh, such a good one!”

Of course the newly built Martian is not going to utter something incoherent like that, because he would have no way of knowing that he is a fake. He would believe for all the world that he is the original Derek Parfit, only moments ago disintegrated in the scanner on Earth. After all, that’s what his brain would tell him, since it’s identical to Derek Parfit’s brain! This shows that we have to treat claims of personal identity, even ones coming straight from the first person’s mouth, with extreme caution.

Well then, given our new no-nonsense attitude, what should we think about Episode II? We have been told that Parfit the would-be space voyager instead stepped out of the cubicle on Earth, and with heart damage. But how do we know that that one is Parfit? Why didn’t Parfit the storyteller tell us the story from the vantage point of the new Martian who also calls himself “Derek Parfit”? Suppose the story had been told this way: “The moment I stepped out of the Martian cubicle, I was told the terrible news that the other Parfit — that poor fellow way down on Earth — had suffered cardiac damage in beaming me up here. I was devastated to hear it. Soon he and I were talking on the phone, and I found myself in the odd position of trying to console him just as I had recently consoled a dying friend…”

If it had been recounted sufficiently smoothly, we might not have been able to resist the thought that this body, the Mars-borne one, is really Derek Parfit. Indeed, Derek Parfit the skilled philosopher–storyteller might even have gotten us to imagine that the earthbound body with the damaged heart was merely a pretender to the Unique Soul linked by birth and by divine decree to the name “Derek Parfit”.

Teleportation of a Thought Experiment across the Atlantic

It seems that the way in which a science-fiction scenario is related is crucial in determining our intuitions about its credibility. This is a point that my old colleague and friend Dan Dennett has made many times in his discussions of philosophers’ crafty thought experiments. Indeed, Dan calls such carefully crafted fables intuition pumps, and he knows very well whereof he speaks, since he has dreamt up some of the most insight-providing intuition pumps in the field of philosophy of mind.

And I have to say that as I was typing Parfit’s story from his 1984 book into this chapter, a little voice murmured softly to me, “Say, doesn’t this remind you of Dan’s foreword to The Mind’s I, his ingenious teleportation fantasy that drew so many readers to our book when it came out in 1981?” And so after the Parfit story had been all typed in, I pulled a copy of The Mind’s I off my shelf and reread its first few pages. I have to say that my jaw fairly dropped. It was exactly the same fantasy, only with planets reversed and sexes reversed, and told in a more American style. There was exactly the same bipartite structure, the first part featuring a “Teleclone Mark IV” that destroyed the original, and the second part featuring a newand-improved version (“Mark V”) that preserved the original.

What can I say? I love both of these stories, one from each side of the Atlantic, whether one is a “clone” of the other or their pedigrees are independent (though that seems unlikely, since The Mind’s I is in Parfit’s bibliography). In any case, now that I’ve got this little matter off my chest, I’ll continue with my commentary on Parfit’s provocative tale (and also, of course, on Dan’s, thanks to the referential power of analogy).

The Murky Whereabouts of Cartesian Egos

The key question raised by Parfit’s tale is this: “Where is space voyager Derek Parfit really, after the teletransportation has taken place in Episode II?” Put otherwise, which of the two claimants to being Parfit really is Parfit? In Episode I, Parfit the storyteller plants a most plausible-seeming answer, but then in Episode II he just as plausibly undermines that answer. At this point, you can probably almost hear Strange Loop #642 intensely identifying with the space traveler and screaming out, “Which of the two would I be?”

To my mind, one cannot claim to have said anything significant about the riddle of consciousness if one cannot propose (and defend) some sort of answer to this extremely natural-seeming and burning question. I think that by now you know my answer to the question, but maybe not. In any case, I’ll let you ponder the issue for a moment, and meanwhile, I’ll go on to tell you more or less how Parfit sees the matter.

This issue lies at the very core of Parfit’s book, and the explanation of his position occupies about a hundred pages. The key notion to which he is opposed is what he dubs “Cartesian Pure Ego”, or “Cartesian Ego”, for short. To put it in my words, a Cartesian Ego constitutes one exact quantum of pure soul (also known as “personal identity”), and it is 100 percent indivisible and undilutable. In short, it is what makes you be you and me be me. My Cartesian Ego is mine and no one else’s, has been from birth and will be to death, and that’s that. It’s my very own, completely private, unshared and unsharable, first-person world. It’s the subject of my experiences. It’s my totally unique inner light. You know what I mean!

I have to admit, parenthetically, that every time I see the phrase “Cartesian Ego”, although my eyes perceive only one “g” there, some part of me invariably hallucinates another “g”, and the image of an egg bubbles up in my brain — a “Cartesian Eggo”, if you’ll permit — a beautifully formed egg with a pristine white shell protecting a perfectly spherical and infinitely precious yolk at its core. In my strange distorted imagery, that yolk is the secret of human identity — and alas, Parfit’s central mission in his book is to mercilessly crush the whole egg, and with it, the sacred yolk!

There are two questions that Parfit does his best to answer. The first one is: When Parfit is teleported to Mars in Episode I, is his Cartesian Ego teleported along with him, or is it destroyed along with his body? The second question, seemingly even more urgent and confusing, is this: When Parfit is teleported to Mars in Episode II, where does his Cartesian Ego go? Could it possibly go to Mars, abandoning him on Earth? In that case, who is it that remains on Earth? Or conversely, does Parfit’s Cartesian Ego simply stay put on Earth? In that case, who, if anyone, is it that debarks from the cubicle on Mars? (Note that we are conflating the word “who” or the phrase “who it is” with the notion of a specific, uniquely identifiable Cartesian Ego.) The temptation to ask such questions (and to believe that these questions have objectively correct answers) is nearly irresistible, but nonetheless, the nearly universal intuitions that give rise to this temptation are what Parfit is out to crush in his book.

To be more specific, Parfit staunchly resists the idea that the concept of “personal identity” makes sense. To be sure, it makes sense in the everyday world that we inhabit — a world without telecloning or fanciful cut-andpaste operations on brains and minds. The fact is, we all more or less take for granted this notion of “Cartesian Ego” in our daily lives; it is built into our common sense, into our languages, and into our cultural backgrounds as profoundly, as tacitly, as seamlessly, and as invisibly as is the notion that time passes or the notion that things that move preserve their identity. But Parfit is concerned with investigating how well this primordial notion of Cartesian Egos stands up under extreme and unprecedented pressures. As a careful thinker, he is doing something analogous to what Einstein did when he imagined himself moving at or near the speed of light — he is pushing the limits of classical notions — and, like Einstein, he finds that classical worldviews do not always work in worlds that are very different from those in which they were born and grew.

Am I on Venus, or Am I on Mars?

In his hundred or so pages of musings on this issue, Parfit analyzes many thought experiments, some dreamt up by himself and some by other contemporary philosophers, and his analysis is always keen and clear. I have no intention to reproduce here those thought experiments or his analyses, but I will summarize what his conclusions are. The essence of his position is that when pushed to its limits, personal identity becomes an indeterminate notion. In extreme circumstances such as Episode II, the question “Which one of them am I?” has no valid answer.

This will be extremely unsatisfying and unsettling to many readers of Parfit’s book, and to many readers of this book, as well. Our intuitions as we grew up on planet Earth have not prepared us for anything in the least like a nondestructive teleportation scenario, and so we clamor for a simple, straightforward answer, yet somehow we also intuit that none will be forthcoming. After all, we could invent Episode III, featuring a destructive teleportation scenario as in Episode I, but with signals simultaneously sent out to receiving stations on Venus and on Mars. In this scenario, shortly after the destruction of the original Parfit body and brain, two brand-new Parfits (both complete with shaving nick) would be assembled more or less simultaneously on the two planets, and now there really doesn’t seem to be any valid claim of primacy for either one above the other (unless you argue that the first one finished should get to claim the honor of the Cartesian Ego, but in that case, we can simply posit that they are assembled in synchrony, thus barring that easy escape route).

To our everyday, downhome, SL #642–style minds, it’s very stark and very simple: one of the Parfits is a fake. We cannot imagine being in two places at once, so we think (identifying ourselves with the intrepid voyager), “Either I’ve got to be the Venus one, or the Mars one, or neither one.” And yet none of these answers is in the least satisfying to our classical intuitions.

Parfit’s own answer is actually closer to the thought that I brusquely dismissed in the previous paragraph: that we are in two places at once! I say it’s closer to that answer rather than saying that it is that answer, because Parfit’s view, like mine in this book, is that these things that seem so black-and white to us actually come in shades of gray — it’s just that in ordinary circumstances, things are always so close to being pure black or white that any hints of grayness remain hidden from view, not only thanks to the obvious external fact that we all have separate physical brains housed in separate skulls, but also thanks to an extensive web of linguistic and cultural conventions that collectively and subliminally insist that we each are exactly one person (this is the “caged-bird metaphor” of Chapter 18, and it’s also the Cartesian Ego notion), and which implicitly discourage us from imagining any kind of blending, overlapping, or sharing of souls.

There is also, I cannot deny it, an absolute certainty, deep down in each one of us, that I cannot be in two places at once. In earlier chapters, I went to great lengths to give counterexamples of many sorts to this idea, and Parfit, too, takes great pains to give other kinds of evidence about the possibility of spread-out identity. In fact, he eschews the term “personal identity”, preferring to replace it by a different term, one less likely to conjure up images of indivisible “soul quanta” (analogous to unique factory-issued serial numbers or government-issued identity cards). The term Parfit prefers is “psychological continuity”, by which he means what I would tend to call “psychological similarity”. In other words, although he doesn’t propose anything that would smack of mathematics, Parfit essentially proposes an abstract “distance function” (what mathematicians would call a “metric”) between personalities in “personality space” (or between brains, although at what structural level brains would have to be described in order for this “distance calculation” to take place is never specified, and it is hard to imagine what that level might be).

Using such a mind-to-mind metric, I would be very “close” to the person I was yesterday, slightly less close to the person I was two days ago, and so forth. In other words, although there is a great degree of overlap between the individuals Douglas Hofstadter today and Douglas Hofstadter yesterday, they are not identical. We nonetheless standardly (and reflexively) choose to consider them identical because it is so convenient, so natural, and so easy. It makes life much simpler. This convention allows us to give things (both animate and inanimate) fixed names and to talk about them from one day to the next without constantly having to update our lexicon. Moreover, this convention is ingrained in us when we are infants — at about the same Piagetian developmental stage as that in which we learn that when a ball rolls behind a box, it still exists even though it’s not visible, and may even reappear on the other side of the box in a second or two!

The Radical Nature of Parfit’s Views

To dismantle unconscious beliefs that are so deeply rooted and that have such a degree of primacy in our worldview is an extremely daunting and bold undertaking, comparable in subtlety and difficulty to what Einstein accomplished in creating special relativity (undermining, through sheer logic, our deepest and most unquestioned intuitions about the nature of time), and what a whole generation of brilliant physicists, with Einstein at their core, collectively accomplished in creating quantum mechanics (undermining our deepest and most unquestioned intuitions about the nature of causality and continuity). The new view that Parfit proposes is a radical reperception of what it is to be, and in certain ways it is extremely disturbing. In other ways, it is extremely liberating! Parfit even devotes a page or two to explaining how this radical new view of human existence has freed him up and profoundly changed his attitudes towards his life, his death, his loved ones, and other people in general.

In Chapter 12 of Reasons and Persons, boldly entitled “Why Our Identity Is Not What Matters”, there is a series of penetrating musings, all of which have wonderfully provocative titles. Since I so much admire this book and its style, I will simply quote those section titles for you here, hoping thereby to whet your appetite to read it. Here they are: “Divided Minds”; “What Explains the Unity of Consciousness?”; “What Happens When I Divide?”; “What Matters When I Divide?”; “Why There is No Criterion of Identity that Can Meet Two Plausible Requirements”; “Wittgenstein and Buddha”; “Am I Essentially My Brain?”; and finally, “Is the True View Believable?”

Even though all eight of these sections are rife with insight, it is the last section that I admire the most, because in the end, Parfit asks himself if he really believes in the edifice he has just built. It is as if Albert Einstein had just realized that his own ideas would bring Newtonian mechanics crashing down in rubble, and then paused to ask himself, “Do I really have such deep faith in my own mind’s pathways that I can believe in the bizarre, intuition-defying conclusions I have reached? Am I not being enormously arrogant in rejecting a whole self-consistent web of interlocked ideas that were carefully worked out by two or three centuries’ worth of extraordinary physicists who came before me?”

And although Einstein was exceedingly modest throughout his lifetime, his answer to himself (though to my knowledge he never wrote any such introspective essay) was, in effect, “Yes, I do have this strange faith in my own mind’s correctness. Nature has to be this way, no matter what other people have said before me. I have somehow been given the opportunity to glimpse the inner logic of nature more deeply and more accurately than anyone else before me has. I am unaccountably lucky in this fact, and though I take no personal credit for it, I do wish to publish it so that I may share this valuable vision with others.”

Self-confidence, Humility, and Self-doubt

Parfit is far more prudent than this. His conclusions, to my mind, are just as radical as those of Einstein (although I find it a bit of a stretch to imagine radical ideas about the ineffability of personal identity leading to any marvelous technological consequences, whereas Einstein’s ideas of course did), but he is not quite as convinced of them as Einstein must have been. He feels confident, but not absolutely confident, of his edifice of thought. He doesn’t think it will start to shake and soon tumble down if he stands on it, but then again he admits that it just might do so. Let us hear him express himself on this topic in his own words:

[The philosopher of mind Thomas Nagel] once claimed that, even if the Reductionist View is true, it is psychologically impossible for us to believe this. I shall therefore briefly review my arguments given above. I shall then ask whether I can honestly claim to believe my conclusions. If I can, I shall assume that I am not unique. There would be at least some other people who can believe the truth.

[A few pages later] .…I have now reviewed the main arguments for the Reductionist View. Do I find it impossible to believe this View?

What I find is this. I can believe this view at the intellectual or reflective level. I am convinced by the arguments in favour of this view. But I think it likely that, at some other level, I shall always have doubts.…

I suspect that reviewing my arguments would never wholly remove my doubts. At the reflective or intellectual level, I would remain convinced that the Reductionist View is true. But at some lower level I would still be inclined to believe that there must always be a real difference between some future person’s being me, and his being someone else. Something similar is true when I look through a window at the top of a sky-scraper. I know that I am in no danger. But, looking down from this dizzying height, I am afraid. I would have a similar irrational fear if I was about to press the green button.

….It is hard to be serenely confident in my Reductionist conclusions. It is hard to believe that personal identity is not what matters. If tomorrow someone will be in agony, it is hard to believe that it could be an empty question whether this agony will be felt by me. And it is hard to believe that, if I am about to lose consciousness, there may be no answer to the question “Am I about to die?”

I must say, I find Parfit’s willingness to face and to share his self-doubts with his readers to be extremely rare and wonderfully refreshing.

Morphing Parfit into Bonaparte

In the last paragraph quoted above, Parfit alludes to a thought experiment invented partly by philosopher Bernard Williams and partly by himself (in other words, invented by a Williams–Parfit hybrid who might be called “Bernek Willfits”), in which he is about to undergo a special type of neurosurgery whose exact nature is determined by a numerical parameter — namely, how many switches will be thrown. What do the individual switches do? Each one of them converts one of Parfit’s personality traits into a different personality trait belonging to none other than Napoleon Bonaparte (and I literally mean “none other than”, as I will shortly explain). For example, one switch makes Parfit far more irascible, another switch removes his repugnance at the idea of seeing people killed, and so forth. Note that in the previous sentence I used the proper noun “Parfit” and the pronoun “his”, which presumably is an unambiguous reference to Parfit. However, the whole question here is whether or not such usages are legitimate. If switch after switch were thrown, converting Parfit more and more into Napoleon, at what stage would he — or rather, at what stage would this slowly morphing person — simply be Napoleon?

As I have already made clear, asking exactly where along the line the switchover would take place makes no sense from Parfit’s point of view, for what matters is psychological continuity (i.e., proximity in that quasimathematical space of personalities or brains that I suggested a little while ago), and that is a feature that comes in all shades of gray. It is not a 0/1 matter, not all-or-nothing. A person can be partly Derek Parfit and partly Napoleon Bonaparte, and drifting from the one to the other as the switches are thrown. And this doesn’t merely mean that this person is becoming more and more like Napoleon Bonaparte — it means that this person really is slowly becoming Bonaparte himself.

In Parfit’s view, the Cartesian Ego of Napoleon is not indivisible, nor is that of Derek Parfit. Rather, it is as if there were a slider on a wire, and the two individuals (who are not really “individuals” in the etymological sense, since the word means “undividable”) can be merged or morphed arbitrarily by sliding that slider to any desired position on the wire. The result is a hybrid person, a tenth or a third or halfway or three-quarters of the way between the two ends — whatever proportions one wishes, ranging from Derek Parfit to Deren Parfite to Dereon Parpite to Deleon Parapite to Doleon Paraparte to Daoleon Panaparte to Dapoleon Ponaparte to Napoleon Bonaparte.

Most people, unlike Parfit, want there to be and are convinced that there must be, at each point along the spectrum of cases, a sharp yes–no answer to the question, “Is this person Derek Parfit?” This is the classical view, of course — the view that takes for granted the notion of Parfit’s own Cartesian Ego. And so most people are put into the awkward position of having to say that there would be a particular spot along the wire at which all of a sudden, without warning, at the instant when the slider passes it, the Cartesian Ego of Parfit would poof out of existence, to be replaced by that of Napoleon Bonaparte. Where only a moment ago we had been dealing with a somewhat personality-modified Derek Parfit, but still and all a Derek Parfit who genuinely felt Derek Parfit’s feelings, now we suddenly have a modified Napoleon Bonaparte, and he feels Napoleon’s feelings, and not Parfit’s whatsoever!

The Radical Redesign of Douglas R. Hofstadter

The intuitions being pushed here are very emotional and run very deep in our culture and our whole view of life. It gets particularly intense for me when I insert myself into this scenario and start imagining the personality-trait substitutions that a neurosurgeon might carry out by throwing one switch after another.

For example, I begin by imagining that, upon the throwing of Switch #1, my love for Chopin and Bach is replaced by a visceral loathing of their music and that instead, a sudden yet powerful veneration for Beethoven, Bartók, Elvis, and Eminem flowers in “my” brain.

Next, I imagine that Switch #2 causes me every single weekend (and every other spare moment as well) to elect, instead of designing ambigrams or working hard on my book about being a strange loop, to spend hours on end watching professional football games on a huge-screen television and delightedly ogling all the busty babes in the beer ads.

And then (Switch #3) I imagine my political leanings being turned on their head, including my decades of crusading against sexist language. Now, I come out with “you guys” every other sentence, and anyone who objects to it I chortlingly deride as “a politically correct monkey” (as you might imagine, that’s just one of the milder epithets I use).

With the next switch, I jettison my lifelong inclination towards vegetarianism and trade it in for a passion for shooting deer and other wild animals — and of course the larger they are, the better. Thus, after Switch #4 has been thrown, I just adore toppling elephants and rhinos with my trusty rifle! The most fun thing in the world! And each time one of the noble beasts bows humbly down to my triumphant bullets, I give one of those “I’m great” jerks with my arm, which one so often sees when a football player scores a touchdown.

And lastly, needless to say, after Switch #5 has been thrown, I totally agree with John Searle’s Chinese Room experiment, and I think that Derek Parfit’s ideas about personal identity are a complete crock. Oh, I forgot — can’t do that, since I never think about philosophical issues at all!

You may have noticed that when I discussed Switch #1, I put quotes around the word “my” when talking about the brain in which a veneration for Ludwig, Béla, Elvis, and Eminem flowers. From there on out, though, I didn’t bother with the quote marks, but I probably should have. After all, everything I suggested in the paragraphs above is the diametric opposite of what I consider core me-ness. Letting go of even one of these traits is enough to make me think, “That person wouldn’t be me any more. That couldn’t be me. That is incompatible with the deepest fiber of my being.”

Of course we can imagine milder changes, such as an alternate life in which I somehow never ran into Prokofiev’s violin concerto #1. That would be another version of me, and surely a more impoverished one, but it would still feel like me, to this me. Or we can imagine that I still eat hamburgers on occasion but feel guilty about it, or that once in a blue moon I voluntarily turn on a football game on TV. These are shades of gray that create a halo of “possible Dougs” around the Doug that I happen to have become, thanks to a million accidental events that have befallen me over the decades, and thanks to hundreds of particular individuals who happen to have entered my life (and millions of others who never did, not to mention an infinite number of counterfactual individuals who never entered my life!). We don’t normally think of “who/what/how I am” in such shades of gray, but there they are, spelled out a bit, in my case.

On “Who” and on “How”

I might add, by the way, that I think the word “who” is sometimes granted a bit too much subliminal power, in much the way as are the personal pronouns “he” and “she” (you may recall my brief interchange with Kellie about pronouns applied to animals, in Chapter 1). In the 1980’s, Pamela McCorduck wrote a history of artificial intelligence with the provocative and ingenious title “Machines Who Think”. The word “who” in the title conjures up an image radically different from our knee-jerk associations with standard machines such as can-openers, refrigerators, typewriters, and even computers; it suggests that with at least certain machines, there is someone “in there”, or as Thomas Nagel would say, “there is something it is like to be that machine” (a hard phrase to translate into other languages, by the way). It implicitly suggests, once again, a sharp, black-and-white dichotomy between a set of hypothetical “machines that think” (such machines would merely think but would have no inner life) and a different set of hypothetical “machines who think” (these machines would have an inner life, and each one would be a particular someone).

It has often seemed to me that ultimately, when I am thinking about who my closest friends are, it all comes down to how they are — how they smile, how they talk, how they laugh, how they listen, how they suffer, how they share, and so on. I think to myself that the innermost essence of each friend is made up of thousands of such “how” ’s, and that that collection of “how” ’s is the answer — the full answer — to “Who is this person?”

It may seem that this is purely a third-person, external perspective, and that it takes away, or even denies, the whole first-person perspective. It may seem to short-change or even to casually dismiss the “I”. I don’t think so, however, for I think that even to itself, that is all an “I” is. The rub is, an “I” is very good at convincing itself that it is a lot more than that — in fact, that is the entire business that the word “I” is in! “I” has a vested interest in continuing this scam (even if it is its own victim)!

Double or Nothing

At long last, we return to the Venus-versus-Mars enigma of Episode III. I have already told you that Parfit somewhat sidesteps the question by simply denying the existence of Cartesian Egos, and thus saying that the question has no meaningful answer. But in his book he also refers quite often to what he terms “double survival”, which means essentially that he is simultaneously in two places at once. More than once, he writes that double survival is hardly equivalent to death (which would be no survival), and that the number two should not be conflated with the number zero! So what is he really saying? Is he saying that there is no answer to the question, or is he saying that in fact he has been doubled, and there are now two Derek Parfits?

It’s hard for me to figure this out since I think he says both things often enough that one could argue it either way. But where do I come down on this issue? I think I come down on the “two me’s” side. At first, this almost sounds as if I am embracing the Cartesian Ego theory, just imagining that the egg is cloned and two identical Cartesian Egos come to exist, one on Venus and one on Mars. But then SL #642 would start screaming, “Which one is me?” It sounds as if I haven’t answered the question at all, or as if I want to have my egg on Mars and eat it too, on Venus.

In order to regain some semblance of consistency, I have to return to SL #641’s theme in the dialogue, which is that the “I” notion is, fundamentally and in the end, a hallucination. Let’s let Episode III, my teleportation scenario with fresh copies on Venus and Mars and no copy left on Earth, apply to me instead of to Parfit. In that case, each of the new brains — the one on Mars and the one on Venus — is convinced that it is me. It feels just like it always felt to be me. The same old urge to say, “I am here and not there” zooms up in both brains as automatically as when someone taps my knee and my leg jerks upwards. But knee-jerk reflex or not, the truth of the matter is that there is no thing called “I” — no hard marble, no precious yolk protected by a Cartesian eggshell — there are just tendencies and inclinations and habits, including verbal ones. In the end, we have to believe both Douglas Hofstadters as they say, “This one here is me,” at least to the extent that we believe the Douglas Hofstadter who is right now sitting in his study typing these words and saying to you in print, “This one here is me.” Saying this and insisting on its truth is just a tendency, an inclination, a habit — in fact, a knee-jerk reflex — and it is no more than that, even though it seems to be a great deal more than that.

Ultimately, the “I” is a hallucination, and yet, paradoxically, it is the most precious thing we own. As Dan Dennett points out in Consciousness Explained, an “I” is a little like a bill of paper money — it feels as if it is worth a great deal, but ultimately, it is just a social convention, a kind of illusion that we all tacitly agree on without ever having been asked, and which, despite being illusory, supports our entire economy. And yet the bill is just a piece of paper with no intrinsic worth at all.

Trains Who Roll

In Chapters 15 through 18, I argued that each of us is spread out and that, despite our usual intuitions, each of us is housed at least partially in different brains that may be scattered far and wide across this planet. This viewpoint amounts to the idea that one can be in two places at once, despite our initial knee-jerk rejection of such a crazy-sounding thought. If being in two or more places at once seems to make no sense, think about reversing the roles of space and time. That is, consider that you have no trouble imagining that you will exist tomorrow and also the next day. Which one of those future people will really be you? How can two different you’s exist, both claiming your name? “Ah,” you reply, “but I will shortly be getting there, like a train pulling through different stations.” But that just begs the question. Why is it the same train, if in the meantime it has dropped some passengers off and picked others up, perhaps changed a car or two, maybe even its locomotive? It is simply called “Train 641”, and that’s why it is “the same train”. It’s a linguistic convention, and a very good one, too. It is a very natural convention in the classical world in which we exist.

If Train 641, heading east from Milano, always were to split up in Verona into two pieces, one that headed north to Bolzano and one that continued eastwards to Venice, then we would probably not call either half “Train 641” any longer, but would give them separate numbers. But we could also call them “Train 641a” and “Train 641b”, or even just leave them both as “Train 641”. It might happen, after all, that upon reaching Bolzano, the northern half always veers suddenly eastwards, and likewise that upon reaching Venice, the eastern half always veers suddenly northwards, and the two halves always rejoin and fuse together in Belluno, on their way — or rather, on its way — to Udine!

You may object that trains have no inner perspective on the matter — that “641” is just a third-person label rather than a first-person point of view. All I can say is, this is a very tempting viewpoint, but it is to be resisted. Trains who roll and trains that roll are the same thing, at least if they have sufficiently rich representational systems that allow them to wrap around and self-represent. Most trains today don’t (in fact none of them do), so we don’t usually give them the benefit of the “who” pronoun. But maybe someday they will, and then we will. However, the transition from one pronoun to the other won’t be sharp and sudden; it will be gradual, like the fading of the belief in Cartesian Egos as people grow in sophistication.

The Glow of the Soular Corona

It may strike you that this whole chapter has been predicated upon such weird science-fiction scenarios that it has no bearing at all upon how we think about the real world of real human beings, and their real lives and deaths. But I believe that that is mistaken.

I have a close friend whose aging father Jim has Alzheimer’s Disease. For some years my friend has been sadly watching his father lose contact, bit by bit, with one aspect after another of the reality that only a few years ago constituted the absolute bedrock, the completely reliable terra firma, of his inner life. He no longer knows his address, he has lost his former understanding of such mundane things as credit cards, and he isn’t quite sure who his children are, though they look vaguely familiar. And it is all getting dimmer, never brighter.

Perhaps Jim will forget his own name, where he grew up, what he likes to eat, and much more. He is heading into the same terrible, thick, allenveloping fog that former President Reagan lived in during the closing few low-huneker years of his life. And yet, something of Jim is surviving strongly — surviving in other brains, thanks to human love. His easy-going sense of humor, his boundless joy at driving the wide open spaces of the prairies, his ideals, his generosity, his simplicity, his hopes and dreams — and (for what it’s worth) his understanding of credit cards. All of these things survive at different levels in many people who, thanks to having interacted with him intimately over many years or decades, constitute his “soular corona” — his wife, his three children, and his many, many friends.

Even before Jim’s body physically dies, his soul will have become so foggy and dim that it might as well not exist at all — the soular eclipse will be in full force — and yet despite the eclipse, his soul will still exist, in partial, low-resolution copies, scattered about the globe. Jim’s first-person perspective will flicker in and out of existence in other brains, from time to time. He will exist, albeit in an extremely diluted fashion, now here, now there. Where will Jim be? Not very much anywhere, admittedly, but to some extent he will be in many places at once, and to different degrees. Though terribly reduced, he will be wherever his soular corona is.

It is very sad, but it is also beautiful. In any case, it is our only consolation.