We believe that Greg is a frog. It is almost certain that Julius is a rhino. There is little chance that Lily is yellow. It is certain that if either 'Greg is a frog' or 'Julius is a rhino' but not both then Mary put down the milk. It is probable that if 'Lily is yellow' or 'Greg is a frog' or both then John went to the kitchen. It is unlikely that if 'Greg is a frog and Lily is yellow' then Bernhard is a swan.
It is almost certain that either 'Bernhard is a swan' or 'Julius is a rhino' but not both.
It is almost certain that either 'Bernhard is a swan' or 'Julius is a rhino' but not both.
It is highly unlikely that either 'Bernhard is a swan' or 'Julius is a rhino' 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
  0.75::factA.
  0.95::factB.
  0.1::factC.
  %hop1
  1.0::factX:-xor(factA,factB).
  0.7::factY:-or(factC,factA).
  0.2::factZ:-and(factA,factC).

  %hop2
  conclusion:-xor(factZ,factB).

  query(conclusion).
  
Either 'Bernhard is a swan' or 'Julius is a rhino' but not both.