Thoughts on personal identity
Last updated: 01.08.2021
Published: 11.16.2020

Thoughts on personal identity

Recently, in an effort to clarify my views about personal identity, I looked back at the discussion of the topic in Part III of Derek Parfit’s Reasons and Persons. This post is an attempt to grok Parfit’s view more fully than I have in the past.

Parfit’s analysis is an inspiring example of analytic philosophy as a force not just for clarifying concepts or justifying intuitions, but for radically revising how we see the world. Here’s my description of the basic view that Parfit wants to revise (this isn’t the precise version Parfit gives; rather, it’s an attempt to articulate the view as I find it in myself). We have certain ways of relating to the future that seem centrally connected with what will happen to us. If I learn, for example, that someone in the future is going to hit on the head with a hammer, my relationship to this fact differs depending on whether the person in question is me vs., say, Angela Merkel. The difference need not be about the amount of concern: I might well be more concerned about Angela’s future head injuries than about my own. But some other dimension intuitively differs.

In particular, it seems, whether the future hammer-blow victim will be me vs. Angela makes a difference to whether it makes sense for me to anticipate being hit on the head — to expect, as it were, to be there for the inner experiences involved in the blow. Intuitively, of the vast ocean of experience that will take place in the future, I will only be there for a very small subset; just as, of the vast majority ocean of experiences in the past, I was only there for a tiny subset. Before I was born, I wasn’t there for any experiences; and after I die, I won’t be there for any more experiences, ever again.

This seems like a deep difference: the difference between nothingness, blankness, the void, and the bright joy of consciousness, the lushness, energy and intensity of being something, of being alive, awake, here. It’s the infinitely thin line we disappear into when we die; the line with no other side; the direction we travel as we faint and fade — away from home, music, loves, friends, sights unseen, beauties undiscovered; away from everything; nowhere.

Here’s an example of consciousness of this difference, from All Quiet on the Western Front. I include it in an effort to make vivid the stakes of what can seem like fanciful metaphysics. Paul, a German soldier in World War I, is watching his friend and fellow solider die in the hospital:

An hour passes. I sit tensely and watch his every movement in case he may perhaps say something. What if he were to open his mouth and cry out! But he only weeps, his head turned aside. He does not speak of his mother or his brothers and sisters. He says nothing; all that lies behind him; he is entirely alone now with his little life of nineteen years, and cries because it leaves him…. I become faint, all at once I cannot do any more. I won’t revile any more, it is senseless, I could drop down and never rise up again.

And as he leaves the hospital:

Outside the door I am aware of the darkness and the wind as a deliverance. I breathe as deep as I can, and feel the breeze in my face, warm and soft as never before. Thoughts of girls, of flowery meadows, of white clouds suddenly come into my head. My feet begin to move forward in my boots, I go quicker, I run. Soldiers pass by me, I hear their voices without understanding. The earth is streaming with forces which pour into me through the soles of my feet. The night crackles electrically, the front thunders like a concert of drums. My limbs move supplely, I feel my joints strong, I breathe the air deeply. The night lives, I live. I feel a hunger, greater than comes from the belly alone.

Paul, watching his friend die, can look forward to being there for more of life; his friend cannot.

Generally, we treat the fact that we will be there for some set of experiences as the reason it makes sense to be concerned about those experiences in some unique, self-related way. Thus, when a soldier in World War I fears the pain of getting his leg amputated, but not the pain of his fellow’s amputation, this makes sense because he will be there for the one pain, and not the other.

What’s more, we take the physical and psychological connections between future people and our present self as relevant to such concerns because they bear on which future experiences we will be there for, where our “being-there-ness” will “flow” from here. When such a soldier hopes to survive the night, he does not hope, directly, that there is some future person whose psychology, body, and brain bears the right causal connections to his own. Rather, he hopes that he will still be there for experiences had in the morning. His psychological and physical connections to future people are relevant insofar as they indicate, ground, or constitute this fact.

This can make it seem as though, presented with a complete and impersonal description of the physical and psychological connections between my current self and some future people having different experiences, it is still an open and substantive question which, if any, of those future people I will be, and which of those experiences I will be there for. If I am told, for example, that the two halves of my brain will be split and put into different bodies (“Lefty” and “Righty”), each of which will survive, I might wonder: will this be death for me? Will I be there for any future experiences, after this operation? If so, which ones? Lefty’s, Righty’s, both?

Similarly, suppose that if I pay for a certain service, the causal structure in my brain relevant to my memory, personality, and cognitive functioning will be scanned and uploaded into a computer (and perhaps, from there, given some futuristic robot body). I might wonder whether this would allow me to be there to witness and enjoy some much longer future after my biological body fails; or whether the digital being experiencing the future would be someone else — someone very like me (at least initially), and perhaps uniquely dear to my heart, but whose experiences I should no more anticipate than the experiences of, say, my grandchildren, or any other future person. Would paying for this service allow me, one day, to see the glittering cities of the future? Or would I be paying for someone else to do so?

Such questions can seem both substantive and important. Parfit, however, argues that they are neither. That is, Parfit argues that once we have specified all of the facts about the physical and psychological connections between you and future people, there is no further fact about where your “being-there-ness” goes. We can describe the situation in different ways — for example, we can say that your upload is you, or that it is someone else — but there is no deep metaphysical fact that we might get wrong in making this choice. We don’t risk, as it were, wrongly advising you about whether or not you’ll see the glittering cities; you already know everything there is to know; the rest is word choice.

One way of pumping this intuition is to reflect on the fact that there is nothing your upload could do to check whether your wish to see the cities has been fulfilled and your investment justified; looking out on the cities, he will be just as confused as you are now, though perhaps less concerned. A case my girlfriend suggested also pumps this intuition for me (though her purposes in suggesting it were different). Suppose that  Bob1 is scanned on Planet1 and replicated as Bob2 on Planet2, then Bob2 is scanned and replicated as Bob3 on Planet3, and so on, but where everyone thinks it a deep metaphysical truth that their old self “flowed” with them but no further, such that Bob1 thinks that uploading “doesn’t work” as a mechanism of travel to another planet, Bob2 thinks it worked once but not the second time, Bob3 thinks it worked three times, and so on. How could such disagreements be resolved? That said, this intuition pump is very far from a conclusive argument, as we need the inference from “p cannot be checked” (in the sense relevant here) to “p or not p is not a substantive question,” which seems, at least, a very substantive position, and one that plausibly rules out vast swaths of philosophy.

Another way of pumping this intuition is to appeal to the fact that whether or not you’ll be there for a certain set of experiences seems, in some cases, indeterminate. We imagine, for example, a spectrum of possible alterations to your brain, body, and psychology; at one end, we make very little change; on the other, we incinerate your body and build a replica of Angela Merkel from scratch; and in between, we do something in between (altering, say, a given percentage of your body, brain, and psychology to be like Angela’s). It seems clear that you survive some of the operations, and do not survive others; but there are many where it is hard to say, and intuitively, the problem is not ignorance, but the absence of a determinate fact of the matter. Again, I think this is very far from a conclusive argument, as we’d need the inference from “p is indeterminate in some cases” to “p or not p is not a substantive question,” which, again, seems too strong (and epistemicists about vagueness might deny the first premise as well). Still, I still find it helpful, in attempting to grok Parfit’s view, to really imagine facing situations of this kind.

Parfit says much more than I have here in support of his “no further fact” view, but I won’t outline further arguments (or attempt further clarification of what it is for something to be a “further fact” — a notion that I think remains somewhat elusive). Somewhat confusingly, though, despite thinking that disputes about survival just come down to empty disputes about how to describe the same situation, Parfit does think that there is a best description (at least in many cases), a best answer to the empty question of whether, say, your upload is you: namely, your upload is you, as long as there is no other future person who you have similar psychological connection with. More broadly, he thinks that personal identity consists having the right type of psychological continuity/connectedness (call this R-relatedness) with a unique future person (presumably there is also something here about the time at which the future people exist — I’m forgetting exactly how Parfit puts it). But he doesn’t think that this description has the type of normative weight or primacy that we intuitively ascribe to the question of whether or not we will survive a given vicissitude. If this question had a metaphysically substantive answer, it might make sense to base our self-related normative attitudes on what that answer is: e.g., to pay for the uploading because it will, or won’t, allow us to see the glittering cities; to travel by teletransporter, or not, because we will, or won’t, survive the journey. But because it has no such substance, it should not play such a central normative role.

What’s more, the thing that Parfit thinks should play this normative role — namely, R-relatedness, just on its own — gives different verdicts than his favored criteria of personal identity in various cases. Thus, Parfit thinks that your upload is not you, if there are multiple such uploads, or if your body survives on earth, because this violates the condition that only one person in the future can be you (interestingly, the version of you that lives on earth post-scanning also isn’t you, on Parfit’s view — that is, even getting the scan is, in some sense, death for your earthly self, though it is not bad in the way death is). But he thinks uploading is as good as surviving — maybe better, if there are multiple uploads.

This part of Parfit’s view currently seems to me unnecessarily convoluted. In particular, Parfit seems to me overly attached to prohibiting multiple future selves (I think this attachment stems from the idea that “being the same person as” is a 1-1 relation — see David Lewis’s “Survival and Identity” for some discussion, and an alternate proposal). Ultimately, though, on Parfit’s view, it’s a verbal dispute.

What seems less verbal is the question how our attitudes and understanding should alter if we let go of the idea that whether or not I will survive something, or whether or not I will be there for a given experience, is a metaphysically substantive one. Parfit describes his own altered outlook, in one of the most beautiful passages of analytic philosophy I’ve read:

When I believed that my existence was such a further fact, I seemed imprisoned in myself. My life seemed like a glass tunnel, through which I was moving faster every year, and at end of which there was darkness. When I changed my view, the walls of my glass tunnel disappeared. I now live in the open air.

In my own attempt to inhabit Parfit’s view, it has seemed to me that one alteration it requires is to our normal notion of “anticipation.” Suppose that you’re about to be harmlessly brain scanned, such that an upload will one day be created on the basis of the scan. It’s natural to feel like you should only anticipate the experiences either of your future biological body, or of the upload (or neither); that is, that somewhere in the process of the scan, you will “find out” which direction “you” will go, which one you’ve “ended up” as. In particular, in this case, I’m strongly inclined to expect to “end up” as the one on earth: e.g., that what I will experience is going into the scanner, some beeping/whirring etc, then the operation ending, my leaving the hospital, and so on; just as, had the scan occurred while I was asleep, “I” would’ve woken up the next day and continued on with my life, never knowing the difference (something like this intuition was, for a long time, a source of strong resistance, for me, to views like Parfit’s). I now think this much more likely to be the wrong way to think about the situation, and that the right way is to “anticipate” being both people; both the future biological body, and the upload. To look forward to both lives, to plan for both lives, while also expecting, anticipating, that they will be lived separately (I expect that making the full transition to this mode of anticipation would take some effort).

When I try to do this, though, I also notice some other more difficult-to-articulate shift in my sense of the world — or at least, my sense of how the world would be, if this were the way to approach it. In particular, this way of thinking makes “survival” seem much more like a special type of causation. That is, being alive, being myself, becomes less like a process of “flowing” through time as a changing stream of experiences, and more like a special and uniquely direct way of affecting and relating to particular future minds. For most future people, my relationship to them is, as it were, at a distance; if I want to communicate with them, I need to speak or write or record. But I can see and affect the minds of my future selves much more directly; my intentions become their intentions; my memories, their memories; and they, in turn, can see backwards, into me.

Thinking this way, I sometimes slip into thinking of myself as a “time-slice,” where the experiences of the time-slice have the special “I am there for it” property, but none of the experiences of any future people do; rather, future versions of myself are more like especially intimate friends, people who I love and support, towards whom I feel deep understanding and loyalty, but whose experiences fall on the other side of the same chasm that separates my experience from the experiences of other people around me. This can lead to a sense that what ought to be happening is that in each moment “I” — the time slice — should be dying, since the span of experience with the “I am there for it” property should be ending. I then feel a kind of confusion, because “I” seem to be persistently not dying, not disappearing. The electric sky still crackles; the drums thunder. The thing I fear from death has not happened. But is the thing I fear from death impossible, confused? When this body fails, will “I” still be here to hear the drums? Surely not. Surely there is something more at stake for me — the one who wishes to hear the drums — in the final death of this body than in the passing time itself.

I think part of what’s happening here is that some part of me is holding onto the “I am there for it” property as a thing that experiences (including experiences happening now) can have. I try to expect future experiences not to have it, and to transition into identifying which of those experiences are “mine” in some other way; then I notice, as the next moment arrives, that this “I am there for it” property keeps not going away, keeps flowing forward, always (arbitrarily, surprisingly) into the experiences of Joe, this particular human.

Perhaps the remedy, here, is letting go of the “I am here for it” property more fully. It’s not that “I” am here for present Joe experiences, but not for future ones. Rather, whatever my relationship to future Joe experiences is, that is my relationship to present Joe experiences too. Perhaps, that is, “I” am not “here” for any of it. 

Another alternative, advocated for by my girlfriend, is to expand the range of experiences to which we describe the “I am here for it” property — namely, to all experiences. On this view, the “I am here for it” property just is the property that someone is there for it; every experience has the special property your present experience has: namely, being an experience. I expect that ultimately, the “deny that the special property exists” and the “give the special property to everything” views will end up fairly similar.