There is almost no chance that Lily is a rhino. It is probable that Bernhard is a swan. It is likely that Daniel dropped the apple. It is highly unlikely that if 'Daniel dropped the apple and Lily is a rhino' then Mary went to the hallway. We doubt that if 'Lily is a rhino' or 'Daniel dropped the apple' or both then Winona is a sheep. It is unlikely that if 'Daniel dropped the apple and Lily is a rhino' then Greg is yellow.
It is certain that either 'Daniel dropped the apple' or 'Bernhard is a swan' but not both.
Chances are about even that either 'Daniel dropped the apple' or 'Bernhard is a swan' but not both.
It is certain that either 'Daniel dropped the apple' or 'Bernhard is a swan' 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
  0.02::factA.
  0.7::factB.
  0.7::factC.
  %hop1
  0.05::factX:-and(factC,factA).
  0.2::factY:-or(factA,factC).
  0.2::factZ:-and(factC,factA).

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

  query(conclusion).
  
Either 'Daniel dropped the apple' or 'Bernhard is a swan' but not both.