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Philosophy Looks at Chess

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fburton

I decided to post here because the topic arises from something I read in a book Philosophy Looks at Chess, to which another chess.com poster schack_2 also contributed a chapter. I am hoping maybe he has something to say to this issue. The first chapter is by Bernd Graefrath and is titled To Know the Past One Must First Know the Future: Raymond Smullyan and the Mysteries of Retrograde Analysis. One section of this chapter (p7) concerns Smullyan's rejection of the kind of 'logical positivism' that espouses strict verificationism. He wrote: "This doctrine regards as meaningless any statement that is incapable of verification or refutation" and gives the following retrograde chess problem as demonstrating how "ridiculous" the logical positivist position is.


This is captioned 'Indemonstrable mate in 2 moves'.

Here it is clear that white, whose turn it is, can force mate in 2 moves. The problem is that we are only given this position and do not know the moves leading to it. Therefore, we don't know if black's last move was e7-e5 or if black has previously moved king or rook and so lost castling rights. If one tries to 'demonstrate' a specific mate in 2 moves, it can always be argued that black's previous play is incompatible under chess rules with white's 'chosen' move. This situation is meant to illustrate the fallibility of verificationism.

However, it seems to me that one can demonstrate the solution, only not as a single set of moves. The solution is the indivisible package (A or B), unless or until the previous move is known. Without further information the past can only be known as (A' or B'). Once the past is revealed, a single solution can be demonstrated. If A' then A; if B' then B. Just because there is no single, unique solution given available information doesn't mean one cannot make a general statement about the solution, in this case 'mate in 2 for white'.

My question is: where is the problem with this interpretation of Smullyan's example? What am I missing??

FISH2D

If I may express my most humble opinion here.....It is an insult for one brilliant mind to be discovered in comformity. One shall not allowed to be analyzed by others for any reasons,unless the purpose of the study itself contain no rational solution to begin with.


 

 


 

zborg

Yikes.  This is one scary thread.

Do you speak with the (dead) spirit of Bertrand Russell?  Or is it the drugs you are using?

Check out Richard Rorty, he just might bring you back to to earth.

varelse1

Looks like the sort of solution only a philosopher would miss.

zborg

Indeed, Rorty decamped from the field.  But he left a great legacy.

varelse1

Assuming a) Black can castle,

and b) White cannot capture en passant,

is mate in 2 possible?

Casual_Joe

I've always considered myself more of an illogical negativist.

fburton
varelse1 wrote:

Assuming a) Black can castle,

and b) White cannot capture en passant,

is mate in 2 possible?

I think it has to be either a) Black can castle because their last move was e7-e5 (it can't have been e6-e5 otherwise the white king would have been in check - illegally) or b) Black's last move wasn't e7-e5 in which case castling isn't allowed. If a) then dxe6 and a8=Q#. If b) then Kd6 and a8=Q#. Both mate in 2.

zborg

We can all sleep easier now.  Whew.

varelse1

One problem with that. White has no a-pawn. So cannot play a8=Q+.

unless you meant g8=Q+. In which case, black can castle first (if permissible), and sidestep. W#ere's the mate?

fburton

I meant g8=Q#, sorry - not sure why I typed a8 instead?!

If Black can castle, then 1.dxe6 O-O-O 2.b7#.

fburton
schack_2 wrote:

Not much I can say on that chapter, sorry.  It was all over my head.

Ah, okay - thanks for the comment. I am starting to wonder if it is over my head too and I just don't know it! Undecided

zborg

You need a stiff drink, and a bit less philosophy.  Enjoy it.

fburton

Hehe.. good idea. Laughing

revnice

>we are only given this position and do not know the moves leading to it. 

Without the coordinates, we don't know if the board has been flipped either.

AKJett

1.dxe6 wins as if black can castle you mate and if he can't then the move is illegal and you have to mae a different move- hence Kd6 followed by mate

1.Kd6 doesnt mate in two in all cases as black can castle and Kd6 is not illegal if he can

Beat that;D