Re: The Game of Life

From: Jerry Clark <>
Date: Tue, 07 Dec 1999 17:32:59 +0000

Christopher Maloney wrote:

> Jerry Clark wrote:
> >
> > Christopher Maloney wrote:
> >
> > > Jerry Clark wrote:
> > > >
> > > > Such 'Life' evolution raises an interesting question: These SAS's would ...
> > > > Sooner or later a physicists would hear about
> > > > this new development and the realisation would be made that their universe
> > > > *is* a Life simulation.
> > >
> > > Would it? This is a questions I've thought about some. Would the
> > > fundamental mechanism of the life simulation be deducible by these
> > > SAS's? Perhaps the only things that would be "knowable" by these
> > > SAS's would be higher level structures, which they might interpret
> > > as, for example, eleven dimensional quantum mechanical strings, or
> > > something.
> >
> > I didn't say that the fundamental life simulation would be deducible by these
> > Life SAS's, just that they would begin to play around with the 'Life' game and
> > then notice a correspondence between some of the structures they were
> > discovering in their Life simulations and some of the structures their
> > particle physicists were discovering. Once such a coincidence had been
> > noticed they'd be able to develop testable hypotheses that would go to
> > show that their universe was a Life world, and then they'd be left with
> > trying to calculate the boundary conditions (probably impossible in their
> > case).
> But, what you've just described is the deduction by these Life SAS's that
> they live within a fundamental life simulation! So you've contradicted
> yourself.

My fault: I meant that the fact that their own world was a Life simulation would
perhaps not be *directly* deducible (i.e. by 'boiling down' their seeming laws of
physics until they got to '23/3', the Life rules), or at least much less likely than

discovering Life first and building up a larger and larger library of larger and
Life objects (as we are currently doing) until a correspondence is noted between
the larger members of this library and the smaller members of their physicists'
library of fundamental 'particles'. At this point I'd say that the Life rules had
discovered but perhaps not deduced.

> I was trying to suggest that this deduction might be completely
> impossible to them -- that their life world might look like something
> completely different, because, as I suggested, only "higher level
> structures" might be available. I don't know what that means,
> exactly. I'm sure there's been research on this idea -- I know
> there's a vast body of literature on the game, and I'm not knowledgable
> about it at all.

I don't see any hard reason why such a deduction/discovery should be
impossible. I'm not totally familiar with the literature either. Obviously
(as in my extreme example) some information about the fine structure
of their world would be inferred by whatever scientific roundabout route,
but the same goes for our investigation of our world. When was the last
time you had direct experience of a muon?

> > > But, assuming that the lowest level structure of their world is
> > > discernable, I would expect there to be a significant difference
> > > between the measure of those creatures and the measure of other
> > > creatures - us perhaps.
> > >
> >
> > I don't know on what grounds you make that assumption but I'll go
> > along with it. I'm definitely not assuming that our universe is a
> > game of Life.
> Right, well, I'm guessing from this response that you didn't
> understand what I was trying to say. Mea culpa. I explicitly
> assumed that our universe is *not* a game of life, and
> then I went on to conjecture about why we don't find ourselves
> in such a world.

Well to be fair you assumed this further down as part of an argument,
unless I missed some previous posting on account of being new to
this mailing list. But I do disagree with your argument...

> > >
> > > So if we further assume that our universe is *not* a game of life,
> > > and if the AUH is true, then by the SSA I would conclude that the
> > > probability of any SAS finding itself to be in a game of life is
> > > probably zero. That is, the set of SAS's inside a game of life is
> > > of measure zero relative to the set of SAS's inside universes like
> > > ours.
> >

How do you deduce that the prob of being in a game of Life is 0? I under-
stand all the stuff about measure (I'm a mathematician) but where do
you get the Life-like universes vanishing?

> > > In the bizarre nature of infinite sets, not all SAS's are in
> > > universes like ours, but in fact the probability of being in a
> > > universe like ours is 100%.
> And here I make a desperate, arm-waving leap, from the idea that
> I am a random sample, to the conclusion that SAS's "like me" are
> the most numerous. Whatever "like me" might mean, I think it's
> fair to guess that it wouldn't include SAS's inside a game of life,
> unless you're talking about the ones generated within the UD.

No I mean the one's you get 'for free' by running Life sim on a large
enough random field. (Take digits of pi if you don't like 'random').

I agree: your leap is a desparate, arm-waving leap. My SAS within a
Life simulation could be justified in making the same leap, surely. Even
though he/she/it would be by your argument totally wrong.

> > I don't believe in infinite sets. But I'd accept a rephrasing along the
> > lines of "the probability of being in a universe like ours is very close
> > to 100%". Still like to see the reasoning though. (Or perhaps a reference).
> What does this mean, "I don't believe in infinite sets?" Do you
> believe in the number 42? Do you believe in green? Do you believe
> in (pick any human)?

I was being a bit cheeky putting the belief in such bald terms, but I do sort
of mean it. I think arguments about sets being vanishingly small are a bit
suspect in this sphere of philosophy (and also avoidable: on could take e.g
a computation theoretic approach and use the a priori measure to assign
'probabilities' to the existence of SSA's).

Yes, I believe in the number 42, the colour green and my Uncle Mike.

> > > > More interestingly still: when are *we* going to discover some
> > > > CA or similar which
> > > > turns out to be *our* universe? In my lifetime I hope.
> What does "CA" stand for??

Cellular automaton. Life but generalised in terms of rules, dimension, number of
poss. states. etc. Sorry not clear. To reveal a personal prejudice, I have a very
strong hunch that our universe *is* a CA of a particular type, but we can let that
go if you like...

Received on Tue Dec 07 1999 - 08:31:42 PST

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