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Subject: Re: Chess is not like coin tossing

Author: Ratko V Tomic

Date: 02:03:14 05/22/01

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> If you tune your TV to an unused channel and watch the
> static, your brain will create meaning.

You are not trying to hint that the spiritual masters from
Sirius are not really sending the encoded messages in the
TV screen noise? :)

Actually, your brain will create a meaning out of some
noisy electric signals caused by photons striking your
retina. You may think of it as the "real-world," but it is
just some private little toy model made up by your brain
as it correlates all those seemingly chaotic electric pulses
(i.e. any meaning is a "created meaning").

> Since they are designed to produce a specific result, it's
> hard for me to understand why people praise any suite's
> predictive powers.

They do produce ratings within hours, which may take months
for SSDF/ELO method. So, they're a perfectly valid model for
predicting SSDF list (whether that is important is another
matter).

The nontrivial/significant aspect of the suites is that
there _exist at all_ so microscopically small sub-sets of all
the chess positions which can statistically predict program's
performance in real games. That is, the suites extract much
more information from tiny samples of positions, far beyond
what a coin tossing model (the SSDF method) would from similar
size samples of positions. After a few dozen positions in a
single game, the coin tossing model (regular ELO) predicts
almost nothing about the future performance of a program,
while a good suite will produce predictions (after its few
dozens evaluations) which the coin tossing model will take
3+ orders of magnitude more positions to match for accuracy.


> It's like a magician who puts a bunch of colored balls in a
> bunch of colored boxes, then covers his eyes and tells you
> which color box has which color ball inside it.
> Of course he'd know which box contains which ball.
> He's the one who put them in boxes.

You could argue the same way against any physics experiment which
produces predicted results. Indeed, the physicst arranges the
experimental set-up just right to make it follow the desired behavior.

The essential aspect is that in order to actually "fix" such "rigged"
arrangement, the physicist uses theoretical models which
are much more economical to run through than the real thing (the
actual reality run on the full set-up). That is the point of the
models, like the toy aircraft one runs in the wind tunnel or on
a computer simulator -- they're much cheaper and less risky to
run than the full scale reality run. And for the magician, yes,
he needs the economical and effective models of human perception
and resoning loopholes to rig his set-up, too.

The same goes for the test suites or a careful analysis of a single/few
games and the program evaluation outputs. Without relying on such
economy of efforts, the models (or seeing patterns in apparent
randomness), one could never improve a chess program (e.g. if
one had to wait months for thousands of games, where only the
final outcome, i.e. 1.58 bits/game is extracted, in order to
find out whether any given change strenghtens the program).



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