[Haskell-cafe] and [] = True; or [] = False

Miguel Mitrofanov miguelimo38 at yandex.ru
Mon Apr 26 08:31:00 EDT 2010

Forgot about this one:

Bjorn Buckwalter wrote:
> What got me thinking about this was the apparently incorrect intuition
> that 'and xs' would imply 'or xs'.

No. See, "and" is very close to "for all", and "or" is similarly close to "exists". For example, the statement "all crows are black" means just "this crow is black AND this one too AND another one on 
the tree is also black AND..." etc.

Now, obviously, all real dragons can fly. But it doesn't mean there is such thing as a "real dragon".

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