2. Philosophy - Stefano Franchi

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A NACLASTIC SUPPLEMENTS
choice of “plausible” positions. This means that we must read “legal” as “acceptable to a
competent chess player,” e.g. a grandmaster. As a consequence, the required coincidence
between A and B becomes far less trivial than it may appear. The incompetence of an au-
tomated chess player, in fact, could be measured by the size of the two side areas of the di-
agram, since A and ~B includes all the positions that a competent human player would use
but the machine cannot fathom and, conversely, B and ~A comprehends all the “blunders”
that a grandmaster would never make.
The two outside portions of the ovals must be empty, or, what amounts to the same, it
must be the case that A=B. This set, let us call it AB for brevity, represents the competence,
in the Chomskian sense, of an ideal chess player, be it human or not.
Furthermore, and this is the most interesting philosophical claim, no similar situation
can arise between AB and C.
C
AB
C and ~ AB
C and AB
~C and AB
Aspects of chess
irreducible
to chessboard
configurations
Irrelevant chess configurations
The set C represents the game of chess played “in real life,” the activity we see per-
formed in a chess club, in a living room, or at a park. Therefore, the portion of the diagram
labelled C and ~AB would denote whatever part of the game of chess (and not just the game
of chess in the narrow sense of game that we have seen developed by AI, but chess as an
instance of Spiel) is not captured by rule-produced configurations. For example, shouting
at the opponent, making snide remarks about the opponent’s ability to play the game, etc.,
all relevant parts of the game of chess in the blitzkrieg games usually played around the
formal tournaments, would certainly qualify as instances of the first set, e.g. C and ~AB.
Conversely, ~C and AB would stand for legal configurations of pieces on the chessboard
that have nothing to do with the game itself: for example, opening moves that the theory of
the game has discarded, at least for the time being, as unproductive, would qualify as mem-