On 28/09/2015 2:35 pm, Stathis Papaioannou wrote:On 27 Sep 2015, at
10:32 PM, Bruce Kellett <[email protected]
<mailto:[email protected]>> wrote:
On 25/09/2015 2:58 pm, Stathis Papaioannou wrote:
On 24 Sep 2015, at 6:07 PM, Bruce Kellett <[email protected]>
wrote:
On 25/09/2015 12:53 am, Stathis Papaioannou wrote:
You present "closest continuer theory" as if it is
obviously correct, and it is not. In any case, even granting the
theory, why should the causal or physical connection make a
difference? I've sometimes encountered this claim in these
discussions but it is just ad hoc.
The theory is no more ad hoc than any other theory of personal
identity. When we seek to encapsulate an intuitive notion in
language, any attempt could be criticized as being ad hoc, so that
charge is of no substance.
It's ad hoc to say that if one copy differed from the original by 1%
and the other copy by 1.001%, then the 1% copy is the continuation of
the original and the other copy a different person. It sounds like
something made up by legislators rather than philosophers, like an
arbitrary cutoff for a speed limit.
That is a contrived situation. The full theory has a defined metric
(which may or may not be a personal preference) by which one
quantifies the differences between copies (or potential other
persons). That metric will specify when differences become too small
to be significant -- we then claim ties for 'closest' continuer. There
need be no conundrums if one does things sensibly.
If you can't "encapsulate an intuitive concept in language" then you
should state that, or conclude that there is something wrong with the
intuitive notion.
I suggest you tell this to Plato and suggest that he withdraws his
Theaetetus! The majority of philosophy (100% for linguistic
philosophers) is the attempt to make the intuitive concepts of
language more precise -- to encapsulate an intuitive notion is language.
But sometimes the conclusion is that the intuitive concept is wrong or
useless. Derek Parfit came to essentially that conclusion about
personal identity by considering duplication thought experiments.
One does not have to follow Parfit in this, or anything else. I think
the confusion arising from thought experiments about duplication of
computerized simulations is just that, confusion. It is only when we
have actually achieved full AI and we can proceed to duplicate that we
can ask those thereby duplicated what they think about it. Until then,
it is all hypothetical, and our common experiences of personal identity,
and the way we judge the identity of others we meet will govern how we
think about personal identity. The concept is not wrong or useless, and
will not be made so by any number of duplication experiences.
But my more substantive dispute was with your assertion that if a
copy arose through random processes then it wouldn't really count as
a continuation of the original. That's like saying that if car fell
together from parts in a junkyard stirred up by a whirlwind it
wouldn't really be a car - even though it functioned exactly like a
car made in a factory.
That analogy does not fly. Your random car is not the continuation of
any previously existing car: the random person appearing in the
Andromeda galaxy is not a continuation of me, no mater how similar it
is to me on the relevant metric. That random object may well be a
person, just as the car in your junk yard is a car -- it is just that
neither is the continuer of any existing person or car.
The person's psychological continuity would be preserved. I consider I
would survive if my psychological continuity was preserved without my
physical continuity necessarily being preserved; in fact, the only
reason I endeavour to have my physical continuity preserved is because
it's the easiest way to preserve psychological continuity.
Preservation of physical continuity without psychological continuity,
for example if someone has a head injury that wipes out all cognitive
function, is not something anyone aspires to.
That might be your opinion, but others beg to differ. It is a common
experience that people feel crises of personal identity after losing
limbs; after mastectomy for breast cancer; after severe facial
disfigurement. I suggest that since it is unlikely that you have
undergone any of these in their more extreme forms, your personal
opinions on the matter count for very little. I have had very close and
personal experience of the latter case -- loss of most cognitive
function with essentially no visible physical change to the body. There
was never any doubt that that body continued to be the person I knew.
One certainly does not aspire to that situation, but if it arises by
mischance, personal identity is not destroyed. Why do many people
continue to love and care for their loved ones, even when they are in
the extreme end states of Alzheimer's? Or in a long lasting coma?
........
The Copernican Principle in conjunction with the observation that
the universe is uniform in all directions is enough.
No, that is not enough. The Copernician principle is not a law of
physics -- or of anything else, for that matter. It is a useful
heuristic, nothing more. The so-called "uniformity of the universe
(isotropy and homogeneity)" is also nothing more than a useful
approximation that can be used only on the largest scales -- when
you average over all local structure. Such arguments have no force
against the position I am arguing.
Your argument misses the point, which is that IF the universe is
infinite and uniform THEN there would be infinite copies of you and
everything you see, and you could not know which of these copies you
were at any moment.
This is false. It is like the old probability problem of how many
people you need in a room for there to be a greater than 50%
probability of two having the same birthday. The answer, iirc, is 23.
However, the number required in order for there to be a greater than
50% chance for there to be a person who has the same birthday as you
do is substantially greater. The necessity for copies does not imply
that you are copied.
Think of it this way. Take the Tegmark Type I multiverse and suppose
that you are unique (no copies anywhere. Or better, that our
life-friendly universe is unique). Then, by time reversal invariance,
continue that universe back to the big bang to recover the initial
state. Is that initial state impossible? Or any less likely than any
other potential initial state? Duplicates there will be in the
multiverse, but there is no necessity that you, or our observed
O-region, be duplicated.
It's possible that there are no copies of you, but it seems
implausible. There would have to be infinite copies of other things,
but not you. What makes the non-copied configurations special?
Nothing. It is just that they are a priori as likely as any other
configuration.
And even if you are duplicated as Tegmark suggests, so that there are
many copies far outside our O-region, or even our particle horizon,
then there is absolutely no possibilitiy of any interaction between
these copies, so their existence or non-existence can have no effect
on you, so they are irrelevant -- in principle, not just FAPP.
They cannot interact with each other, but they are psychologically
continuous with each other.
That is a meaningless assertion. Can you suggest any operational way in
which you could establish the truth of such an assertion? Are you
suggesting that psychological influences can travel faster than light?
Objects outside our Hubble volume cannot now interact with us; objects
outside our particle horizon can never have interacted with us and can
never do so in the future. The expansion of space makes these
interactions impossible. Psychology is not exempt from these physical facts.
You can't know which copy is generating your mind.
So what? That is another useless assertion.You are you. It does not
matter how many non-interacting copies there are. Given Leibniz's
identity of indiscernibles, there is only ever one person given even
this 'psychological continuity'.
If you were implemented in two parallel simulations on two computers
running in lockstep, you would not be able to interact with your copy,
and you would not be able to know which computer you were being
implemented on.
Again, so what? Can this make any operational difference?
Alternatively, it could be said that your mind was distributed across
the two computers.
No. That is a silly statement.
If one of the computers were switched off, your mind would continue
running, unable to notice that anything unusual had happened.
Which simply means that the scenario you describe is operationally just
the situation of one person. The only thing that making copies achieves
is that the environments will differ, so that the copies will diverge.
Consequently, they cease to be the same person after the odd nanosecond
or two. Anything else is hypothetical nonsense because not achievable in
practice.
The situation then is just like that with the disjoint worlds of the
MWI in QM: the separate worlds are disjoint -- non interacting -- so
their existence has no bearing on you or your future. In fact,
Susskind and others have identified Tegmark's level I multiverse with
the MWI of quantum mechanics. I think this identification is
nonsense, but the relevance of the potential copies is the same in
both cases -- zero!
It is not zero if you could be any of the copies.
Demonstrate to me how this makes an operational difference. If it makes
no measurable or operational difference, then, the relevance of the
copies is precisely zero.
There is reason to believe that in fact the universe is infinite and
uniform; but if it is not, which is possible, the conditional
argument still stands. So, do you think you would experience the
world differently if there were infinite copies of you and of every
possible variation of you?
No. Not that I believe that there are such copies, but even if there
were, they would be of zero consequence for anything whatsoever.
What would it mean for probability if your mind were spread over
infinite copies?
Nothing, because it would make no operational difference to anything --
even if such a concept made any sense at all.
Bruce
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