[extropy-chat] Personal Identity Bis

[Lee Corbin]

Randall writes

>> Again, the DVD has no label, you carry the label by
>> observing the system trajectory.
> 
> I agree that the label consists of the system trajectory.
> Just because we don't have knowledge of a thing at a given
> time, however, doesn't mean that the thing doesn't exist.

I think that you are referring to the history of a particular
system. Given two identical CDs, even down to scratches,
I agree that there is a fact of the matter as to which one
historically was the original and which is a copy. 

It's just that I can think of no important consequence of the
answer to the question "which is the original?".  If the two
are identical, then for *all* purposes they are interchangeable.
And isn't that the only relevant question here, or am I missing
something?

>> Knowledge is information, and information is very important
>> in this unverse, from QM (two systems in the same quantum
>> state are not distinguishable in principle) to singularities.
> 
> I think that this is misapplied, here.  If we had two systems
> in the same quantum state, we might not be able to measure an
> internal difference, but we certainly can distinguish them; if
> we can't, then how do we know we have two?  Taken literally,
> the statement "two systems are indistinguishable" is a logical
> contradiction.

Yes.  They differ by location, at least, even if we agree to regard
their histories as even more unimportant. 

Lee