From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Sun Mar 11 2001 - 07:43:30 MST
On Tue Mar 6, Eliezer wrote:
> Likewise, just as a complete examination of all extant genomes would
> probably be enough for an SI to reconstruct the branching of a
> long-vanished evolutionary tree,
I strongly doubt it will require an SI. Lets assume ten million species
(10^7) each with an average genome of 10 gigabases (10^10). (A few are
much bigger, most are much smaller. So you have to work with ~10^17 * 2 / 8
bytes of information. That is *way* less than the number of atoms in a mole.
Aggregate computing capacity on the planet currently is probably circa 10^25
Ops per year and most of that is heavily underutilized.
It isn't the case that you have to compare *everything* with *everything* else.
You can select a few dozen or a few hundred candidate genes, highly conserved
through evolution, construct a "master" genome symbol table using a hash
function that maps "similar" sequences into the same bin, then find the
closest genomes by scanning "outward" from the conserved regions among
the closely related genomes, working your way through the nonconserved regions
around those genes (where matching gets more difficult). You don't really even
need the "biological" information so you compare insects with insects, plants
with plants, etc.
Approaches similar to this have already worked out the simple mammalian
tree using only a "few" genes. The detailed map between the human, mouse
and rat genomes (i.e. what chromosome breaks, joinings, inversions, etc.)
have occured has been worked out fairly well too.
Now, what will be more difficult will be developing the hypothetical
paths that related to evolutionary branches that dead-ended where
we only have fossil evidence and no DNA. In those situations
(e.g. the Cambrian explosion) we are likely to only be able to
work out probable DNA sequences that might have generated the
body forms and these will still be pretty hypothetical.
I think we will have the processing capacity to deal with the problem long
before we have the genome sequences to feed to the net to unwind evolution.
> so too it should be possible to examine
> all extant accounts and determine whether reports of miracles, however
> distorted and changed by the passage of time, originated in an observation
> or a fictional invention.
>
> And whether pre-1492 religions are true or false is *certainly* knowable.
Hmmmm, I haven't followed the thread back in its entirety, but I would
probably differ with this. Simply because humans are not accurate recorders
of "what really happened", I think anything that relies on human
observation for its assertions is going to be difficult to verify.
With tracing evolution, I can read the code and read it again and again
until I have an error rate that is consistent with the assertions I
want to make. I don't see how you can do something similar with observations
made centuries ago when there were no "recordable" media available.
I'd also disagree with the "certainly" part unless you can assert that
nanotechnology enabled civilizations could not have set the "Stage"
to make it "look" a certain way. They could have created the situations
refered to as "miracles" or have muddied the record to make them seem
to have occured to some "arbitrary" level of accuracy. I think you
have to clarify whether you mean "true" in a supernatural sense
or "true" in the illusionary sense (human senses recorded the
physical phenomena which come down to us as recorded stories).
I think you have a further problem verifying whether or not they
are "true" if this all happens to be a simulation.
Robert
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