On 4/2/2015 8:55 PM, Bruce Kellett wrote:
The only reason that the dovetailer might have to worry about time limitations is if it
is actually a physical computer. Physical computers have to contend with such things as
physical laws, the finite speed of light, the properties of materials, the generation of
heat (entropy) and the need to remove that heat to a safe distance before everything
melts down. If your computer is not a physical device, then it has none of these
limitations, and there is no such concept available as the 'speed' of the computation,
the 'time for each step', or anything of this sort. From our external concrete
perspective, the whole thing is instantaneous, or it enters statis at some point and
gets nowhere. For a non-physical computer these things are equivalent.
So without a physical computer you have no dynamics. A mere ordering of states is still
a static thing, and the dovetailer does nothing useful that could not more easily be
done by referring to a normal number.
Why would it not have the same dynamics as in any Platonia version of physics, e.g. a
block universe simulated in a digital computer? The states don't even have to be computed
in their inherent time order.
This is why I have said several times in previous posts that you rely on an underlying
notion of physical time, and an underlying physical computer, in order to make your
computation dynamic and not static. What you say above does not let you escape from this
conclusion, it merely reinforces it. The problem of time is your undoing.
I think the UD necessarily takes unlimited time. Given any particular state the UD will
visit that state infinitely many times and compute infinitely many different successive
states. It doesn't halt, so all the different successor states are never completed. These
states may be indexed by some internal time, per Barbour.
Brent
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