Re: FIN Again (was: Re: James Higgo)

From: Jacques Mallah <>
Date: Wed, 29 Aug 2001 13:39:41 -0400

>Jacques Mallah writes:
> > The problem comes when some people consider death in this context.
>I'll try to explain the insane view on this, but since I am not myself
>insane I will probably not do so to the satisfaction of those that are.
>I have mixed feelings about this line of reasoning, but I can offer
>some arguments in favor of it.

    I guess you mean in favor of FIN. How about against it too, since you
have mixed feelings?

> > The insane view however holds that the mind of the "killed" twin
>somehow leaps into the surviving twin at the moment he would have been
>killed. Thus, except for the effect on other people who might have known
>the twins, the apparent death is of no consequence.
>It's not that the mind "leaps". That would imply that minds have
>location, wouldn't it? And spatial limits? But that notion doesn't
>work well.
>Mind is not something that is localized in the universe in the way
>that physical objects are. You can't pin down the location of a mind.
>Where in our brains is mind located? In the glial cells? In the neurons?
>The whole neuron, or just the synapse? It doesn't make sense to imagine
>that you can assign a numerical value to each point in the brain which
>represents its degree of mind-ness. Location is not a property of mind.

    A computationalist would say that the mind is due to the functioning of
the brain, and thus is "located" where the parts that function are.
    But this is totally irrelevant. Suffice it to say that a mind is
associated with that brain, while a different mind would be associated with
a different brain.

>Hence we cannot speak of minds "leaping".

    I remind you that _I_ never said they leap, could leap, or that such a
thing is logically possible at all. I said only that the insane hold such a
view, which many posters on this list do. Whatever they may mean by what
they say, the effect is best described as saying they think minds leap.

>It makes more sense to think of mind as a relational phenomenon, like
>"greater than" or "next to", but enormously more complicated. In that
>sense, if there are two identical brains, then they both exhibit the
>same relational properties. That means that the mind is the same in
>both brains. It's not that there are two minds each located in a brain,
>but rather that all copies of that brain implement the mind.

    Nope. That make no (0) sense at all. Sure, you could _define_ a mind
to be some computation, as you seem to want, rather than being a specific
implementation of that computation. But that's a rather silly definition,
since it's a specific implementation that would be associated with conscious
thinking of a particular brain, and thus with measure.
    Of course, even a twin who dies could never have the same computation as
one that lived, since "HALT" is obviously a significant difference in the

>Further support for this model can be found by considering things from
>the point of view of that mind. Let it consider the question, which
>brain am I in at this time? Which location in the universe do I occupy?
>There is no way for the mind to give a meaningful, unique response to
>this question.

    There's no way to know for sure, you mean. OK, I agree with that. You
can still guess with high confidence. In any case, there's still a fact of
the matter, regardless of whether you know that fact.

>Any answer will be both wrong and right.

    That makes no sense. The answer will be either wrong XOR right, for a
particular mind; but you can't know for sure which of those minds is you.
Hence you use indexical Bayesian reasoning or "SSA".

>In this model, if the number of brains increases or decreases, the mind
>will not notice, it will not feel a change.

    Surviving minds won't notice a change. Dead minds won't feel a thing,
which is the reason death sucks.

>No introspection will reveal the number of implementations of itself that
>exist in a universe or a multiverse.

    True, although with the SSA you can make some reasonable guesses.

>This is only dangerous if the belief is wrong, of course. The contrary
>belief could be said to be dangerous in its way, if it were wrong as well.
>(For example, it might lead to an urgent desire to build copies.)

    Even supposing the logical belief to be wrong - what's so dangerous
about building copies? In any case, that would require a lot more tech than
we have.

> > I have repeated pointed out the obvious consequence that if that were
>true, then a typical observer would find himself to be much older than the
>apparent lifetime of his species would allow; the fact that you do not find
>yourself so old gives their hypothesis a probability of about 0 that it is
>the truth. However, they hold fast to their incomprehensible beliefs.
>This is a different argument and has nothing to do with the idea of
>"leaping", which is mostly what I want to take issue with.

    Sure it has to do with it, because it proves "leaping" doesn't happen.

>All this argument shows is that measure or probability decreases with time.

    Exactly right. Thus no FIN.

>The implications of this for how minds should regard changes in their
>numbers of implementation are complex and IMO unresolved.

    Nope, sorry, you're wrong again.
    1) Measure decreases with time. 2) Number of implementations decreases
with time. 3) Independently of that, logic says measure = # of
implementations. Are facts 1, 2, and 3 unrelated? I think not.

>(For example, is adding a new implementation to be desired as much as the
>destruction of one implementation is to be avoided?

    That depends on your feelings (utility function). Personally I'd say
no. In any case, having a baby is less important than not killing someone,
I would say. Human rights and all that, American of me.

>What about size, are big implementations better than small ones?

    I don't see why that would matter. However, it might be argued that
since a brain can mathematically implement a computation more than one way,
a large brain might have more implementations than a small one does. I hope
that can be proven false.

>How about speed, does it matter if the implementations get out of phase,
>how much does it affect probability and measure?)

    Again, I see no reason why that might matter. If one brain is sped up,
its measure per unit time will of course increase, but the total measure
will only depend on how many computational steps the brain is eventually
able to make before stopping.

                         - - - - - - -
               Jacques Mallah (
         Physicist / Many Worlder / Devil's Advocate
"I know what no one else knows" - 'Runaway Train', Soul Asylum
         My URL:

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Received on Wed Aug 29 2001 - 10:41:16 PDT

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