There is a better than even chance that Lily is a lion. It is improbable that Greg is a swan. Chances are slight that Mary dropped the apple. It is probably the case that if 'Greg is a swan and Lily is a lion' then Julius is a rhino. It is probably not the case that if 'Mary dropped the apple and Lily is a lion' then John went to the bedroom. It is certain that if 'Lily is a lion' or 'Mary dropped the apple' or both then Daniel got the milk.
It is highly unlikely that 'John went to the bedroom' or 'Julius is a rhino' or both.
It is highly unlikely that 'John went to the bedroom' or 'Julius is a rhino' or both.
It is certain that 'John went to the bedroom' or 'Julius is a rhino' 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
  0.6::factA.
  0.1::factB.
  0.1::factC.
  %hop1
  0.7::factX:-and(factB,factA).
  0.25::factY:-and(factC,factA).
  1.0::factZ:-or(factA,factC).

  %hop2
  conclusion:-or(factY,factX).

  query(conclusion).
  
'John went to the bedroom' or 'Julius is a rhino' or both.