Re: Objective Meaning Must Exhibit Isomorphism

From: Lee Corbin (
Date: Wed Mar 12 2008 - 08:23:30 MDT

Stathis writes

>> To me, that's as if we perfectly emulate a person's 48hr
>> life quite a few times without incident. Then in some run of that
>> single computer a God-particle level cosmic ray strikes at
>> midnight on Monday, and the rest of the computation takes
>> off in an entirely random and different direction, probably no
>> longer emulating the same person at all.
>> To you, is that equivalent also?
> No, the cosmic ray would cause a different computation.

Sorry---did you get the wrong impression from my word "equivalent"?
I meant for the tremendously powerful cosmic ray to completely
change the computation, and so the Tuesday run would *not* in
any way be like the Tuesday computation that was supposed to
have run. (By "equivalent", I had meant equivalent to your fake
diskette substituted for the real Sj from Monday.) Please, is
this clear now? Or is there is some miscommunication here?
See the next few sentences just to be sure.

> But if instead the cosmic ray set off a Monday computation
> that otherwise wouldn't have happened,

Well, yes! That's just how I read you!

> that would be the same as a deliberate Monday computation
> from the point of view of the internal observers.

Eh? The cosmic ray strikes at 12:00 midnight = 12am Tuesday . :-) Just to make
sure that we are talking about something after the last state on
Monday and before the first state on Tuesday.

> What you refer to as the significance of a causal link in computation
> is equivalent to what is sometimes called the requirement that the
> computational system "handle counterfactuals". For example, if some
> event on Monday had been different, then [it] should be taken into account
> by the computation and events on Tuesday would also have been
> different; whereas if Tuesday just happened due to a random event this
> sort of sensitivity to Monday would be lacking.

I think I understand.

> The idea is that if the computational system doesn't handle counterfactuals
> it is not only useless for computation, but also that it doesn't give rise to
> consciousness.

Let's see if I understand you. If at 4pm on Monday we deliberately intervene
and change the state of the person's consciousness (say we introduce a slight
ringing, mild tinnitus, in his ears), then his subsequent remainder-of-Monday/
Tuesday experience is slightly different, the difference growing chaotically
of course.

I'm not sure what you mean by "the computational system doesn't handle
counterfactuals": *any* computational system will "handle" tiny damage
that creates a "counter-factual" in our usage here, no? Now some of
those will be so extreme that the person (subject) is killed, but others
will just mean a slightly different 8 + 24 hours. Right?

> But while it is obvious that a computation that doesn't
> handle counterfactuals is useless to an external observer, it isn't
> obvious that it would lack an internal observer. You would have to
> invoke seemingly magical effects to explain how the computation knows
> or cares that it hasn't been "properly" implemented when there is
> nothing in the physical states underpinning it which indicates this.

I think I agree: In other words, like my "tiny damage" above?

>> >> What is the appeal to you and Schmidhuber and the rest of
>> >> the gang to all that dust comprising 0.99999999999 of your
>> >> experience? That would seem to me to induce fatalism.
>> I mean something like this: Suppose that I hear that an
>> extremely large asteroid by sheer luck is barreling down on
>> the Earth at thousands of kilometers per second. I see this
>> as a big, big hit on my runtime. (We're all going to die.)
>> Why, in the Tegmark example, there is no other Lee Corbin
>> for about 10^10^29 lightyears from here. So for me personally,
>> not to mention all the people I love, this (to me) is very bad
>> news.

"Bad news", of course, to the instance *here*. But by my lights,
the total Lees in almost all the solar systems are unaffected. Still---
this instance does often worry about its own skin.

>> How is it for you? If 0.99999999999 of you (say in the visible
>> universe 10^42 ly across), is unaffected by the asteroid, why worry?
> You're assuming that you somehow know that you are the "real" Lee
> Corbin, as opposed to all those simulations in Platonia.

Eh? No, not at all. To me Platonia is a configuration space, but
only the Lees in the Tegmark Levels 1, 2, and 3 get runtime.
To me, Platonia doesn't host simulations (emulations) because
it's timeless.

> But if the theory you scoff at is for the sake of argument right, there
> is no reason to posit a separate, concrete universe at all. And you can
> still hope that the computational branches where the asteroid misses
> the Earth are of higher measure than the ones where it hits.

I see. For now :-)


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