We believe that Mary went to the office. There is a better than even chance that Brian is a rhino. There is little chance that Julius is yellow. It is highly unlikely that if 'Julius is yellow' or 'Mary went to the office' or both then Lily is a lion. We believe that if either 'Brian is a rhino' or 'Julius is yellow' but not both then John grabbed the apple. It is highly unlikely that if either 'Brian is a rhino' or 'Julius is yellow' but not both then Bernhard is green.
There is a better than even chance that either 'Bernhard is green' or 'Brian is a rhino' but not both.
There is a better than even chance that either 'Bernhard is green' or 'Brian is a rhino' but not both.
It is improbable that either 'Bernhard is green' or 'Brian 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.
  0.6::factB.
  0.1::factC.
  %hop1
  0.05::factX:-or(factC,factA).
  0.75::factY:-xor(factB,factC).
  0.05::factZ:-xor(factB,factC).

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

  query(conclusion).
  
Either 'Bernhard is green' or 'Brian is a rhino' but not both.