On Sun, 11 Jul 1999, Alastair Malcolm wrote:
> From: Jacques M Mallah <jqm1584.domain.name.hidden>
> > [...] The idea is just that all mathematical stuctures exist. Yes,
> > stuctures that explicitly specify everything fall into that category. But
> > so do possible laws of physics, such as the laws that are needed to run a
> > Turing machine. A running TM is a mathematical structure, but is
> > qualitatively different from a stucture that explicitly specifies the
> > state of each memory unit as a function of time. So all TMs would exist
> > and they would run all possible programs.
> > It is of course also possible to have a not-quite-everything
> > hypothesis in which only such stuctures exist, which would be easier to
> > deal with. This would not simplify physics as much as the everything
> > hypothesis, but if it worked, would just be a new theory of physics and
> > simpler than our existing ones.
>
> Your first sentence above implies a Tegmarkian view.
Perhaps you mean to say that Tegmark has a somewhat Mallahhian
(Mallah-esque? Mallahhan? Mallah-like? Mallahhoid? Mallahly?
AntidisMallahhenterian? I've never had to turn my name into an adjective
before) view? He does to some extent but makes some mistakes.
BTW I am not saying that I *believe* the everything hypothesis,
just that I don't think it has been ruled out.
> It seems from what you
> say that within a subset of all the mathematical structures, all possible
> TM's run. Am I right in supposing from this you are in favour of a hierarchy
> with all possible mathematical structures at the top (Tegmark), but with
> some of these generating universes via TM's (Schmidhuber)?
Hierarchy? I wouldn't put it that way. Just that some
mathematical stuctures are Turing machines and some Turing machines run
universe simulation programs. I do expect that such universe sim.
programs would *implement* brain-like computations just as a real
universe would.
> One other
> question, if I may: your 4th sentence above talks of a qualitative
> difference between (what I presume is) 2 kinds of running TM's. Could you
> please explain what this difference is - aren't they both just mathematical
> structures, in essence?(Are you just distinguishing universe-generating TM's
> from general-case TM's?)
No, you misunderstood completely. I was not talking about a
difference between 2 kinds of Turing machines. I was talking about the
difference between a Turing machine, which has laws, on the one hand, as
compared to something that is not a computer at all because the states are
explicitly specified as a function of time.
In the latter case there are plenty of "initial conditions" but no
laws, while in the former case laws exist and there are fewer initial
conditions. Both are mathematical structures, but to say that a *law*
exists is qualitatively different from specifying a bunch of data, even if
the data appears to follow some pattern.
- - - - - - -
Jacques Mallah (jqm1584.domain.name.hidden)
Graduate Student / Many Worlder / Devil's Advocate
"I know what no one else knows" - 'Runaway Train', Soul Asylum
My URL:
http://pages.nyu.edu/~jqm1584/
Received on Sun Jul 11 1999 - 12:12:36 PDT