[extropy-chat] Role of Observer is not Relevant

Rafal Smigrodzki rafal.smigrodzki at gmail.com
Fri Apr 6 20:39:45 UTC 2007

On 4/6/07, Jef Allbright <jef at jefallbright.net> wrote:

  If I may ask another calibrating question:  Do you
> have an opinion on the validity of subjective Bayesian probability?
### Can you expand on the question?


> My POV is that *every* agent is necessarily at the "conceptual center"
> of their universe, and by recognizing this one forms a more accurate
> model of "the way things work", formerly known as "reality."

### Is there any thing else than the "model"?


> Since understanding is essentially modeling, at various levels of
> abstraction, it seems obvious to me that a model gains nothing (and
> necessarily loses by misallocating its probability mass which must sum
> to unity) by positing entities for which there is no evidence.  This
> is not the same as denying the possibility of other entities, (indeed,
> acknowledgment of the inherent incompleteness of any model implies the
> existence of entities outside the model) but only saying there is
> nothing to say about them, so for *all* practical purposes, they don't
> exist.

### Do you think that there are stars that are too far from us to ever
reach the Earth, given the expansion of the universe? If yes, what are
their spectral characteristics? Are they the same as the
characteristics of local stars? Different? In principle unknowable?

If you really believe that your location is not special, then you have
to ascribe the same spectral characteristics to stars in your vicinity
and stars that are too far be seen, even in principle. And if they
have spectral characteristics, they exist.

You cannot say "there is nothing to say" about entities that are
entailed by the existence of known entities.

> The logical incoherence in your rendition of platonism may be more
> apparent if we point out that by positing the "existence" of
> unobservable entities, we must admit that there's nothing to
> distinguish between highly probable unobservable entities and highly
> improbable unobservable entities.  Therefore, it seems to me, the
> "platonic plenum" amounts to a meaningless mush.

### Do you think the likelihood that unobservable stars have the same
spectral characteristics as observable ones is identical to their
likelihood of having any other arbitrary characteristics?

Knowledge about the observable universe informs you about the
unobservable parts as well. You can and should have an opinion about
the probabilities of various unobservable entities (i.e. measures of
the relative sizes of the parts of the plenum that make up these

I can suggest to you "The End of Time" by the theoretical physicist,
Julian Barbour for a discussion of the plenum.


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