There is almost no chance that Mary grabbed the milk. It is probable that Bernhard is green. It is certain that Lily is a lion. Chances are slight that if either 'Lily is a lion' or 'Bernhard is green' but not both then Brian is yellow. There is a better than even chance that if either 'Lily is a lion' or 'Mary grabbed the milk' but not both then John went to the garden. It is highly unlikely that if either 'Bernhard is green' or 'Mary grabbed the milk' but not both then Julius is a frog.
It is certain that 'Lily is a lion' or 'Mary grabbed the milk' or both.
It is certain that 'Lily is a lion' or 'Mary grabbed the milk' or both.
Chances are about even that 'Lily is a lion' or 'Mary grabbed the milk' or 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.
  1.0::factC.
  %hop1
  0.1::factX:-xor(factC,factB).
  0.6::factY:-xor(factC,factA).
  0.05::factZ:-xor(factB,factA).

  %hop2
  conclusion:-or(factC,factA).

  query(conclusion).
  
'Lily is a lion' or 'Mary grabbed the milk' or both.