Re: The Copy Paradox

Hal Finney (
Thu, 13 Nov 1997 13:51:31 -0800

Wolfkin,, writes:
> I still see a difference between stopping and starting the *same*
> program (which is held in memory until restart),

Whoa. You want the program to be HELD IN MEMORY? What happens if it
gets swapped to disk? Do you think silicon transistors are better at
retaining identity than the magnetic disk surface?

Suppose you were running as a program, on a time sharing system, and
you're cool about it. "No problem," you say, "since I'm being held
in memory between run slices." "Hate to tell you this," I say, "but
actually this OS swaps you to disk between runs. You've been swapped
in and out a dozen times during the last three seconds." What do
you say? How do you react? Do you believe that you've been constantly

> and starting
> *another* program while stopping the first permanently. We often
> think of two copies of a program as being 'the same' when in fact
> they have features that differ (location, frex).

Now suppose you're running on a network. "No problem," you say, "since
I'm 'the same' program each time because I have the same location."
"Hate to tell you this," I say, "but that network is shared with a few
hundred other programs, and the set of processors you're running on
is constantly changing. Sometimes you're using these processors here,
sometimes those over there, sometimes it even pulls in some units from a
loaner system at the local data bank. Your location has shifted 100
times since we've been talking." What do you say? How do you react?
Do you consider that you've been constantly dying with each shift in

> I would say that such a person has participated only once. :) The
> fact that he has memories which are taken from previous people
> doesn't mean that he *is* those people.

Yes, yes, one of the ground rules is that we're avoiding saying that
A *is* B. All I meant was that he has memories of having gone through
this experience multiple times.

> Assuming that someone who may exist in the future will think that
> they are me doesn't really help me accept the idea that *I* should be
> killed after the copy is made.

Suppose you knew someone who was afraid to fall asleep, because he was
convinced that every time he fell asleep he died, and a new version of
him awoke in the morning - someone who had all the same memories, but
a new person nonetheless. How would you try to persuade him that he was