X-Message-Number: 17993
Date: Thu, 22 Nov 2001 00:49:58 -0700
From: Mike Perry <>
Subject: MWI, Indiscernibles, Instantiations

Both William Henderson (#17981-2) and Robert Ettinger (#17983) comment on 
some of my remarks on "identity of indiscernibles" and other such issues. A 
few responses seem appropriate.

Henderson (#17981, duplicated in #17982):

>Perry: Again, identity of indiscernibles makes it unnecessary to assume
>more than one *identical* copy of you exists at any given instant
>the full implications of this are rather profound).
>Yes the implicaions of this are profound!

This is discussed in my book and actually is more complicated than it may 
appear. That is, some things can effectively be considered identical (and 
are) even though physically distinct.

>What a frightening specture it
>is to see that once rational researchers are going so far out of the
>limb of impluasibility. Come on! Even one identical copy of me is
>rediculous. Look, if you want to postulate other universes to help with
>your wave theory OK, but where oh where is that dependable scientific

No, what you don't realize is that MWI itself *requires* the existence of 
near-copies of you, other earths and so on, which would occur at least rarely.

>I think I need to
>here remind everyone of an ancient theory that was proved through
>philosopy and deuction to be true even though in reality it was not. I
>can't quite remember the theorist name form my first year in philosophy,
>something like, Heracules. He put forward the theory that a hare could
>never catch up to a tortois of the tortois had a small head start.

Zeno. Nobody took his argument seriously in its literal sense--obviously 
the hare could catch the tortoise (actually I think it was Achilles 
catching the tortoise, same difference). But to show why his argument 
didn't work required mathematical sophistication not then available, that 
is, the idea that infinitely many catch-up steps might be performed in 
finite time.

But, on the idea of "crazy" theories that seem to defy rationality, 
sometimes one goes to such lengths to account for subtle but real phenomena 
that otherwise resist explanation. And sometimes there are alternatives 
that seem more reasonable at the time, but are eventually discredited. Some 
used to think it was absurd to argue that stars were suns, since they were 
so tiny and faint--but that explanation won the day, though other theories 
also fit the observations, especially before there were telescopes.

Robert Ettinger, #17983:

>Mike Perry says that even if phenomenological quantons, such as phonons,
>could be used for quantum computing, that would not militate against MWI. I
>think it would, because it would increase the likelihood that all quantons
>are phenomenological.

"Phenomenological" apparently implying, I gather, "unreal" in some critical 
sense. In MWI I know that "particles" really don't have a separate 
existence but are virtual effects of waves--to me that amounts to calling 
them "phenomenological" in some sense, yet MWI lives on. And I'll confess 
I'm not really up on the full meaning of "phenomenological"--I've looked it 
up in my Shorter OED but what it says there is a little too vague to really 
deal with the issue here.

>  After all, even MWI people do not appear to dispute the
>possibility of a finer-grained reality such as strings underlying the
>particles previously regarded as ultimate.

Yet I don't think string theory would necessarily challenge MWI.

>As for infinities of "you" in MWI, and "identity of indiscernibles"--

Once again, the issue, as I treat it in my book, is more complicated than 
it may seem. Yes, I do allow for cases of physically distinct objects 
(duplicates of persons, say) that, for reasons discussed, can be and are 
treated as one and the same or, more precisely, as instantiations of one 
entity and not separate entities.

>First, I'm pretty sure Deutsch does say there are infinitely many identical
>copies of you in the multiverse--although the precise meaning of this needs a
>long explication.

True, there would be identical copies physically distinct (again 
instantiations), though not identical whole universes (or need not be).

>As for identity of indiscernibles, I don't want to rehash
>that at any great length, but this "identity" is said to apply, for example,
>to electrons--and yet no one claims there is only one electron.

Feynman advanced an argument like that (and a positron, he said, is what 
happens when this electron is moving backward through time); however this 
is not a critical issue as I see it.

>I don't think Mike can have it both ways--claiming on the one hand that you
>and your (identical or close) copies are the "same" and on the other hand
>that there aren't infinitely many copies or near-copies of you having
>infinitely varied experiences, most of which are bound to be miserable.

Well, I see no reason why one must conclude that most of your near-copies 
"are bound to be miserable"--where did this come in? Considered as a 
*possibility* only, I'll grant that no one has disproved it; I don't think 
it's likely myself. Perhaps the idea comes from the thought that, if you 
make a small, random change in your body, it will very likely be 
deleterious and you'll be worse off. And, since the many universes are 
supposed to cover "all possibilities," they must include all possible 
instances of such random changes. Yet the likelihood of such changes need 
not be great at all. Is there any special reason to think, for instance, 
that in most worlds having human-like creatures, most of the creatures 
would have their bones fractured in a few random places rather than none?

>As for choices making a difference, see e.g. Barbour's THE END OF TIME. He is
>more or less in the Deutsch camp, yet he thinks the succession of events or
>"passage" of time is an illusion, other times being only special instances of
>other universes, and Deutsch (sometimes) seems to agree. On the level of
>consciousness, of course we do have free will, and choices do matter, but
>from an Olympian point of view everything already exists, eternal and
>unchangeable--here and there, now and then, everything. (In a way, this would
>also answer Dave Pizer's question about something arising from nothing. There
>is no "arising" in the temporal sense.)

A good comment. Choices do make a difference. And indeed, Deutsch says 
"time doesn't flow" which does fit an Olympian point of view and could 
account for how things got here without postulating "something from nothing."

>Anyway, the future--if there is such a thing--seems to offer lots of
>opportunity for fun, for every taste.

On this I agree, too.

Wishing a great and wonderful future for all (and also happy Thanksgiving),
Mike Perry

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