Re: A calculus of personal identity

From: Bruno Marchal <>
Date: Tue, 27 Jun 2006 16:47:55 +0200

Le 26-juin-06, à 14:28, Stathis Papaioannou a écrit :

> Bruno Marchal writes (quoting SP):
> > > Of course, it is not possible for a third person observer to be 
> >
> > certain about first person mental states, and this would apply to our
> >
> > teleportee: he may feel as if he is the same person as he was prior t
> o 
> > > the procedure, but he might be wrong.
> >
> > If he is a zombie, by definition he feels nothing.
> I am assuming here he is not a zombie, that he has a memory of what
> he felt like pre-teleportation, but that he may be wrong about this.

I am not sure any entity can be wrong about a (first) personal feeling.
The person can only be wrong relatively to some (personal)
interpretation of some (non personal) world (its most probable
(Actually even a zombie cannot be wrong when he asserts, for example,
that he has a headache. But this happens for a different reason: he is
*not* interpreting at all its own words. Feelings have to be conscious
by definition I would say).

> When we remember our past, we are doing something analogous to what we
> do when we look at someone else's account of their first person
> experience and try to imagine what it must have been like to have that
> experience.

All right, but only partially so. We hardly succeed imagining the real
things here, except perhaps twins or doppelgangers, but in both case,
only serendipitously.

> Memories of our past are generally more vivid and hold more
> information than writing, film etc., but there may come a time when
> people directly share memories with each other as easily as they now
> share mp3 files.

Selling, buying, sharing memories belongs to the future of applied
bio-information science, I guess. But still, despite infinite possible
progress in that matter, what will always really be shared will be
numbers and partially similar decoding and interpreting procedures. For
example, the mp3 files contains binary digits, and people share indeed
the same first level decoding machinery (a Mac, a PC, an ipod, etc.).
They does not share the personal experience (ex: for one the music will
makes him/she recall nice memories, for someone else: only bad
memories). Now you make one step further and share the good/bad
memories. This can only partially be done, and then it will be similar
to number-mp3 sharing. To share the first person experience completely
you will have to erase memories for maintaining enough (self-)
consistency, and you will actually fuse the persons. The quantum analog
is quantum erasure of information which allows interference effects
(and thus history-fusion) to (re)appear.
The first person itself is not first person-self-definable (I will come
back on this, but those following the diagonalization post can already
smell this phenomenon: the collection of all computable functions from
N to N cannot be enumerated by a computable function).

> >
> I would agree if I was believing in Nature. As a scientist I am neutral
> > about the existence of nature, but assuming comp "Nature", like 
> > "matter" should not be reified.
> Can you think of any findings in evolutionary biology which count as
> evidence either for or against the existence of a material world? 

We must be very careful here. Evolutionary biology assumes a material
world, and I would say (just apparently against comp) that evolutionary
biology CORRECTLY assumes a material world.
Somehow like a chess player assumes some local chessboard and a car
driver assumes some local car.
It just happen that evolutionary biologists are not so much interested
in the very nature and origin of that material world. They either
define it as a bunch of interacting fields and particles they heard
about, or even more generally just as the object matter of physics,
without looking to the conceptual problem of physics at all.
For example in "consciousness explained" Dennett explictly asserts that
there is no more conceptual problem in physics: only technical problem
would remain.
(This attitude evolves slightly thanks to quantum computation).
Note that this is also the reason why comp cannot threaten evolutionary
biology, quite the contrary, it proceeds according to the same basic
mechanist philosophy. A case can even been made that comp extends
Darwinism by allowing the physical laws to evolve, in some logical or
psycho or theo-arithmetical selection process.

> Of course, most scientists, like most people, assume there is
> a material world out there, but this is not a premiss on the basis of
> which scientific theories stand or fall.

The science or art of doing good pizza does not depend on atoms,
quarks, or waves, still less on the interpretation of those terms. Any
irrefutable (non scientific) fuzzy notion of matter will do.
Most scientist assume a material world, but none make this explicitly,
and matter is just a background decor at least since about 500 after
Biologists are almost all materialist, although nuances can already be
made when comparing molecular biologists and biochemists (my initial
doubt). James D. Watson is even a sort of ultra-atomist: he does
already not believe in molecules, only in atoms (why not elementary
particles? I don't know, ask him).
But metaphysician and theologian does put forward fundamental theories
on the nature of matter and existence. Aristotle does it very
cautiously with an effort for clarity, making most (if not all) of his
propositions about matter refutable (and thus scientific in the sense
of Popper). It is known that his dynamics has been already refuted by
Galileo. It is less known, I think, that his primary notion of,
arguably boolean, material substance has been refuted only recently,
either by experiment like EPR-Bell-Aspect, or by theory through
QM-Kochen-Specker-GHZ (hopefully soon in the realm of experiments).
And then comp, either by UDA or by the lobian interview refutes such a
notion right at the start. And this refutation is quite similar in
spirit, to those provided by Plotinus and some other (neo)platonists.
Note that my work does not refute the existence of matter, but it makes
it devoid of any explanation power (so with Occam ...).
Well, here we are at the crux of what I think comp forces use to revise
in fundamental science and I guess we will have many opportunities to
dig all this in a deeper way.

> I don't understand why you say
> "if duplication (at any level) is a death sentence, then comp is wrong"
> . There must be a *minimal* level of duplication fidelity below which
> consciousness/intelligence is not preserved, no? Or are you using
> "duplication" to mean perfect duplication, in which case how can we
> have different levels of perfection? 

Sorry my quantifier was perhaps unclear. Comp means that there exists a
level of digital substitution of my parts where I survive (or "feel no
difference") in a teleportation experiment (and thus digital brain
graft, duplication ...) where the copy are exact at that (finite,
digital) level.

So comp can be false only if we don't survive any such digital
substitution. This means that teleportation will fail for any level of
So if comp is false it means that even if I copy you at the level of
the quantum quarks for example, you will not survive, nor if I copy you
at the level of strings, etc. This means there is something genuine for
our identity which is not turing emulable.
Of course, once the correct level is chosen, any level corresponding
with a finer grained decomposition of me into parts will work also (but
will be more expensive for nothing but psychological security).
We never can know "scientifically" what is our correct level. We can
only bet on it.

> This is an important point, perhaps *the* most important point in
> Parfit's book. The problem lies with the pronouns, and with the
> psychology on which these pronouns are based. Evolution and
> grammarians never anticipated the kind of duplication experiments we
> have been discussing!

But theologians always have! Before and after JC. In almost all big
civilizations. Ideas similar to functional substitution appears in
Nagarjuna's answer to Milinda first question (in the "Question to King
Milinda, ref in my thesis), in Plato, in Plotinus (arguably), in
Augustine, in Descartes, and many others. I believe we don't consider
those anticipations seriously because we are brainwashed somehow by
1500 years of state appropriation of theology and the desire by some
strong power (mainly the catholic church) to keep the "fundamental"
question in their (mostly authoritatively defended) territory.
I am not even sure we could say that evolution did not anticipated
this. Of course evolution did not really anticipate anythings, but our
genetical apparatus obviously relies on self-duplication since the
amoeba, so that duplication has been already exploited heavily at some
(molecular) level.

> If I undergo destructive teleportation, how should I describe what
> happens? If I say, "I am destroyed in Brussels" then how can I say
> that I survive the procedure? If I don't say "I am destroyed in
> Brussels" then who *is* destroyed as part of the destructive scanning?

It is here that I would say that the 1/3 person distinction is crucial.
A computationalist wanting to be grammatically and semantically as
clear as possible should just say: my previous body is destroyed in
Brussels. He guesses that he (first person) will survive the procedure.
And of course nobody (really meaning nosoul, or no-one) is destroyed as
part of the destructive procedure.

> So when I say, "I am destroyed in Brussels and reconstituted in
> Moscow",

The problem is that in such an expression "I" is ambiguous. Like you
said, our everyday life (but not our speculative theology or science)
does not prepare us for applied computationalism. "I am destroyed in
Brussels" really means that my original third person describable body
is destroyed, not
my first person "I". The body, for a computationalist is really just a
(third person description) of a local, current vehicle.

> what I really mean is, "a certain instantiation, or token, identifying
> as Stathis-in-Brussels is destroyed, then another instantiation
> identifying as Stathis-in-Moscow is created, such that the two
> instantiations taken together identify as a single individual, or
> type, persisting through time, Stathis-in-Brussels-then-Moscow." 

All right. But I would not identify a token with an instantiation (for
the sake of later nuances, it is not a key point here). Now with your
description, a non-computationalist can take it as an argument against
comp. Indeed, if you identify a single individual by taking together
the two third person (non-overlapping) instantiations, you will have a
problem with duplication which makes the instantiation overlapping. I
would say that the only thing which can be qualified as a first person
identity, is its own (uncommuncable) experiences. It is not something
admitting any third person description, although here G* would add
nuances ...

> It can only be made unambiguous by introducing the third person POV
> because the "I" refers to different tokens/instantiations depending on
> the stage of the teleportation process: the idea that there is a
> single "I" persisting through time is an illusion, involving looking
> at one's future or past as if from the 1st person POV when in fact the
> 1st person POV is necessarily tied to a single token/instantiation.

All right then. Except that I am not sure I really agree with the idea
that the persisting "I" is an illusion. Here, it is hard for me not
taking account of the main UDA conclusion: th reversal
physics/bio/compscience/theology/numbers. So let me tell you what I
believe, accepting comp and the UDA reasoning: The persisting "I" is
not an illusion, or is less an illusion than its body or time itself.
What could also be an illusion is the feeling that "I" and "you" are
absolutely different, when the difference is only relative.

> This is why I say that "I" live only transiently when I am interested
> in being rigorous, while in everyday life I use the pronoun "I" to
> mean what most people mean by it, and what my human-standard
> psychological makeup tells me it means.

This is hard matter and I don't expect we will settle this in few
posts. I think I see what you mean, and at the same time I believe comp
forces us to believe in the contrary (but I know this is strongly
counter-intuitive for those who thinks a lot on personal identity and
does keep some form of naturalism). The reason is that eventually the
first persons will appear to be the time and space constructors, and
that the first person "I" does not even exists transiently (it needs at
least two instants!). So here, comp could come back toward common
sense: "you" are really defining partially and locally a past and a
future (or many possible futures) like everyday life suggests. Identity
is attached (partially) to connected memories, and all what matters
consists in keeping that connection through the construction of time
for consistency purpose. We are not allow to get others' experiences
for the same consistency reason, so "I" remains invariant to "my"
continuous or computable changes, and actually this is what allows us
to be teleported or duplicated through comp, with giving the right for
all my doppelgangers to say consistently that they are all "me",
persisting through those experience/experiments, and being just
accidentally and relatively (in W or M for example) disconnected. I
think that people, like Lee Corbin, who insists that the W and M
doppelgangers are really himself, should accept the possibility, at
least, that all of us are already the same self, produced by many many
duplications and multiplications made through our biological history.
We are unable to recognize ourself as our selves due to other
evolutionary factors which apparently did bet on some competition among
us. Another is some hidden part of oneself, in this setting. It is
known that hiding information can be a key to learning behavior.

Hope I am enough clear. Many things I want to make clearer here rely on
many points in the UDA. It could perhaps help us to tell if you follow
the UDA reasoning until its conclusion (?) or where would you stop? We
could try to isolate possible misunderstandings.


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Received on Tue Jun 27 2006 - 10:49:00 PDT

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