X-Message-Number: 14178
Date: Wed, 26 Jul 2000 16:58:17 EDT
Subject: Mumbling mindless mantras

My resolve to suspend comments on survival criteria didn't last quite as long 
as I had hoped. Oh, well.

The mantra of "identity of indiscernibles" has fatal problems.

In the first place, two or more objects at different locations (in time or 
space) are in principle easily distinguishable. If there are two otherwise 
identical rocks, one in front of me and one in front of you, only one of us 
is in danger of stubbing his toe, and we can easily see who that is. 

You can, if you wish, choose to CALL two systems the "same" by virtue of 
having the same internal design, or being mutually fungible in most ways, but 
that would be an abuse of language. As for "instantly" switching the 
locations of two otherwise identical systems-even if there were such 
things-that is not possible according to current understanding of natural law.

Feynman once suggested that there is only one electron in the universe. It 
zig-zags a lot in both space and time, in effect being in many places at 
once. I don't know how serious he was about that; "time travel" has its own 
problems. But I'm pretty sure he never made any effort to flesh this out or 
fit it into a coherent framework.

The Bekenstein Bound should also be mentioned here. This applies the 
uncertainty principle to points in phase space, thus providing an alleged 
upper limit to the number of quantum states possible in a system the size of 
a human brain, and therefore an upper limit to the number of distinguishable 

To begin with, this sounds extremely strange just on a common-sense basis 
(not that common sense has much to do with quantum theory). It says that, 
even if you live an indefinite period, and even if the universe is indefinite 
in extent, and even if your adventures are objectively boundless, still as 
long as your brain size is unchanged there is a definite number limiting your 
possible experiences! (Note: this is not a limit only on memory, or on the 
number of experiences allowable in a given time, but rather on your possible 
subjective experiences as viewed by an omniscient outside observer over any 
time period.) 

Looking for flaws in the assumptions, we note several things. First, the 
calculation takes account only of internal coordinates, not of coordinates of 
the system as a whole. Second, it takes account only of currently recognized 
coordinates in phase space, and not of other possible parameters that might 
be revealed by a more advanced science. Third, it even ignores gravitational 
phenomena, which we KNOW exist. Fourth, it ignores possible effects of 
quantum entanglement. All in all, it seems to me the BB has only a minor 
antiquarian interest, and should not be used as a girder in any construction, 
as in Tipler's case.

Finally, it seems likely to me that systems in different locations CANNOT be 
identical even internally. That would be tantamount to saying that the 
context does not affect the system! Everything we know-Newton's Third Law in 
particular-tells us that interactions are always two-way streets. In some 
sense, the system must "know" where it is and what it is doing, and must 
therefore be changed by its environment. You cannot reasonably say that the 
system changes its environment, but the environment does not change the 

Robert Ettinger
Cryonics Institute
Immortalist Society

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