It is certain that Lily is green. Chances are about even that Mary went to the office. It is probably the case that John dropped the milk. It is improbable that if 'Lily is green and John dropped the milk' then Daniel took the apple. It is improbable that if 'Mary went to the office' or 'John dropped the milk' or both then Brian is a swan. It is highly unlikely that if 'John dropped the milk' or 'Lily is green' or both then Bernhard is a lion.
It is likely that 'John dropped the milk' or 'Bernhard is a lion' or both.
It is likely that 'John dropped the milk' or 'Bernhard is a lion' or both.
Chances are slight that 'John dropped the milk' or 'Bernhard is a lion' 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
  1.0::factA.
  0.5::factB.
  0.7::factC.
  %hop1
  0.1::factX:-and(factA,factC).
  0.1::factY:-or(factB,factC).
  0.05::factZ:-or(factC,factA).

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

  query(conclusion).
  
'John dropped the milk' or 'Bernhard is a lion' or both.