Making Light:  Habemus papam ::: April 25, 2005, 07:37 AM

S. Dawson:

  If you treat a religion as a set of propositions ... even religions
  making absolutist truth-claims don't really have to be mutually
  exclusive, because chances are their proposition-sets have some
  elements in common....  So a religion that claims to be definitely
  true doesn't claim all others are wholly false, it only claims the
  others are false insofar as they contradict it....

That argument does not address the issue of mutual exclusivity.
Christians, Hindus, and Atheists all believe that knife wounds hurt,
but that doesn't make their faiths compatible.  If I believe "X and
Y", and you believe "X and not Y", then not both beliefs can be true.
That's what "mutually exclusive" means, and agreement on the "X" parts
doesn't contradict the incompatibility between the whole beliefs.