It is highly likely that Brian is a rhino. It is probably the case that Emily is a mouse. It is likely that John went to the bedroom. It is impossible that if either 'Emily is a mouse' or 'Brian is a rhino' but not both then Fred dropped the milk. It is certain that if either 'John went to the bedroom' or 'Emily is a mouse' but not both then Lily is white. We believe that if 'John went to the bedroom and Brian is a rhino' then Bernhard is a frog.
There is a better than even chance that either 'Brian is a rhino' or 'Lily is white' but not both.
There is a better than even chance that either 'Brian is a rhino' or 'Lily is white' but not both.
There is almost no chance that either 'Brian is a rhino' or 'Lily is white' but not both.

  and(A,B) :- A,B.
  or(A,B) :- A;B.
  nand(A,B) :- not(and(A,B)).
  nor(A,B) :- not(or(A,B)).
  xor(A,B) :- or(A,B), nand(A,B).

  %hop0
  0.9::factA.
  0.7::factB.
  0.7::factC.
  %hop1
  0.0::factX:-xor(factB,factA).
  1.0::factY:-xor(factC,factB).
  0.75::factZ:-and(factC,factA).

  %hop2
  conclusion:-xor(factA,factY).

  query(conclusion).
  
Either 'Brian is a rhino' or 'Lily is white' but not both.