[Haskell-cafe] the problem of design by negation

[Richard O'Keefe]

Design-by-negativity can *be* a way of being creative.
I've lost count of the number of times that I've been
explaining to someone why something can't be done, and
suddenly realised that one of the reasons was invalid
and seen how to do it.

The key is not whether you explore the design space
from a positive end or from a negative end, but whether
you *explore* it.