Re: Observer-moments

From: Nick Bostrom <>
Date: Sat, 18 Sep 1999 01:28:47 +0000

Higgo James wrote:

> How can you have an observer (a consciousness) in a moment (a
> snapshot in time). Think about it. In which snapshot (universe) did
> that thought occur? I am not proposing any solution to this problem
> - just pointing out that any edifice built on the idea of an
> observer-moment is bound to crumble.

While the concept of an observer-moment is problematic in some ways,
I don't think "how long does a thought take" is a real problem. For
it doesn't matter for out computations exactly how finely we devide
up observer-time. If every moment is one minute then the relative
probability that this observer-moment will be in the life of
long-lived Larry rather than short-lived Steve will turn out
approximately the same as if they are only one second long.

Bruno Marchal wrote:

> I would propose to see ``observer-moment" as relative computational
> states
> of sufficiently reflexive universal machines.

It seems reasonable that if brain A works twice as fast as brain B,
then A will tend to have twice as many observer-moments per second as
B. So observer-moments are pieces of subjective time, it seems.

Here are three problems. Does anybody have any ideas how they
should be resolved?

1. What about a brain that is stuck for 10 years thinking the same
thought, but at very high clockspeed - a navel-gazing Jupiterbrain?
Is that one observer-moment or very many?

2. Are highly clear, intelligent, intense observer-moments to be
given more weight than dull ones? Or is there a sharp cut-off where
sentience goes from not having any observer-moments to having
full-blown obsever-moments? Or does all sentience equally have

3. What about obsevers that are not readily separable? Human brains
are quite distinct things so we might not be very familiar with this
situation (though consider split-personalities and subconscious
processing, and persons who have had their corpus callosum
dissected), but could they not arise in artificial intellects? If
consciousness need not always be unified, then how count the

Nick Bostrom
Department of Philosophy, Logic and Scientific Method
London School of Economics
Received on Fri Sep 17 1999 - 17:41:21 PDT

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