There is a better than even chance that Brian is a swan. It is improbable that Winona is a wolf. There is little chance that Julius is a frog. It is certain that if 'Julius is a frog' or 'Winona is a wolf' or both then John left the apple. It is highly likely that if either 'Winona is a wolf' or 'Julius is a frog' but not both then Greg is white. It is almost certain that if 'Julius is a frog' or 'Winona is a wolf' or both then Lily is a lion.
It is unlikely that either 'Julius is a frog' or 'Winona is a wolf' but not both.
It is unlikely that either 'Julius is a frog' or 'Winona is a wolf' but not both.
It is almost certain that either 'Julius is a frog' or 'Winona is a wolf' 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
  0.6::factA.
  0.1::factB.
  0.1::factC.
  %hop1
  1.0::factX:-or(factC,factB).
  0.9::factY:-xor(factB,factC).
  0.95::factZ:-or(factC,factB).

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

  query(conclusion).
  
Either 'Julius is a frog' or 'Winona is a wolf' but not both.