From newshub.ccs.yorku.ca!ists!torn!utgpu!cs.utexas.edu!uunet!morrow.stanford.edu!CSD-NewsHost.Stanford.EDU!CS.Stanford.EDU!costello Tue Jun 23 13:21:23 EDT 1992
Article 6328 of comp.ai.philosophy:
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>From: costello@CS.Stanford.EDU (T Costello)
Subject: Re: 5-step program to AI
Message-ID: <1992Jun20.003223.963@CSD-NewsHost.Stanford.EDU>
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Organization: Computer Science Department, Stanford University
References: <60840@aurs01.UUCP> <1992Jun18.022002.29912@mp.cs.niu.edu> <60842@aurs01.UUCP> <1992Jun18.205639.3093@mp.cs.niu.edu> <60848@aurs01.UUCP>
Date: Sat, 20 Jun 1992 00:32:23 GMT
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In article <60848@aurs01.UUCP>, throop@aurs01.UUCP (Wayne Throop) writes:
|> > rickert@mp.cs.niu.edu (Neil Rickert)

|> .....  Back to chess.
|> 
|> >>> The computer chess program and the human chess player both proceed in a
|> >>> somewhat similar manner.  They construct possible sequences of continuation
|> >>> moves and evaluate the result. 
|> >>I  think this is incorrect.  [...]
|> > So far this does not disagree with my point, that both generate
|> > continuations and evaluate the result.
|> 
|> Sorry, I think perhaps I didn't emphasize the differences in
|> approach strongly or clearly enough.  Let me try again.
|> 
|> Computers generate many positions that are guaranteed to be reachable
|> by legal play from the current position, and then evaluate them for
|> strategic and tactical "goodness".
|> 
|> Humans, on the other hand, (seem to) generate a few positions that
|> are guaranteed to have strategic and tactical "goodness", and then
|> evaluate the possible paths from the current position towards them.
|> 
|> Note that humans do NOT choose nearby, generic positions that are
|> "good".  They choose quite specific positions (or small classes of
|> positions) quite far in the "future" of the game, and then steer
|> towards them.  More on this below.
|> 
|> Humans: choose positions and evauate paths.  
|> Computers: choose paths and evaluate positions.
|> 

I find this fascinating.  I believe that current methods of chess playing by 
computers are far to search driven.  I would like to see more intelligent 
heuristic driven search.  Do you believe or have any evidence etc. that
people do choose positions, and can you characterise the types  of positions
or any properties the positions humans choose seem to have.  

|> We can try to see whether these guesses as to human chess method are
|> reasonable by considering, for example, how well humans and computers
|> play in differing phases of the game.  In the midgame, the evaluations
|> are tenative and there are many, many possibe reachable moves to
|> consider.  By the above hypothesis, humans should do better here, since
|> they "skip" the hard parts.  In the endgame, the position evaluations
|> are relatively easy, and the tree of choices of legal moves (and hence
|> reachable positions) is far less bushy, so the computer should do much
|> better.  Indeed, the relative skill between humans and computers do
|> follow this pattern.
|> 
I must admit this seems reasonable but I find that I can easily get a piece
down in the middlegame against a computer opponent to win by a strategm in the
endgame that plays on the computers weakness.  An human often looks over a hundred moves
ahead in an endgame, especially one that has opposition as an important factor, or
a lot of knights.  Computers don't do well here.  The Berliner chess position is an
example of this.  

|> How it is that humans settle on the few positions that they do, and why
|> it is so likely that they will indeed prove to be reachable from the
|> current position without any untoward side-effects is a mystery.  It
|> also doesn't seem to me to involve anything like "pattern recognition"
|> except in the vaguest of ways.
|> 
Again I would be very interested in any further characterisation of this
process.  Is it process based, that is do they look for a place they
can carry out a strategy?  

|> 
|> The computer and human approaches are as night and day.
|> 

|> 
|> To the contrary, human master players evaluate far *DEEPER* than do
|> computer players (at least, in the mid-game).  They are playing 13, 15,
|> 18 and more plys ahead.  Computers (at the time I read the articles in
|> Science News (and other such places) about this a year or two ago) were
|> just starting to reach 8-12 plys.  (At least, according to my
|> perhaps-faulty memory).  Computers can afford to look far deeper
|> in the end-game, and equal or exceed human capacity.  But not yet in
|> the midgame.

Tal was once asked how many moves he looked ahead, he answered "Only
one, the right one". 

I have been looking at heuristic driven reasoning, and I find that 
good examples are difficult to find.  I would be very grateful
if anyone could explain what they feel the methods or ther underlying
methodology of the human human choice of goals to search for is.

 

|> 
|> But then, I'm not a worker in the field.  "I am only an egg."
|> 
|> Wayne Throop       ...!mcnc!aurgate!throop


Tom


