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August 5 2009, 03:51 PM   #36
on holiday

Location: England
Re: Monday Puzzle #3: "Circular Reasoning"

 Tachyon Shield wrote: oh sorry I thought thread was over. I saw the last post said "such and such is correct" so I thought the winner had been named. Sorry. It still don't make sense though.
Okay, well I might as well give some general help with the puzzle.

Contradiction is a valid tool in reasoning, and arguably the most important. When you chain several logical statements together, it is common to create contradictions with values of some the variables, and that says something important about those variables -- specifically values which cannot appear in any solution.

So for example, if one statement said "blue objects are always hexagons" and another said "hexagons can never be blue", then you can deduce that "blue objects cannot be blue".

This is not a contradiction of the "colour" variable, but is a contradiction of a specific value of the colour variable. This simply means that the colour variable cannot take the value of "blue" in any solution to the problem.

If there are no blue objects, then rules about blue objects are arbitrary and become irrelevant.
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Last edited by Jadzia; August 5 2009 at 04:03 PM.