There is almost no chance that Greg is a swan. It is unlikely that Lily is a lion. We doubt that Gertrude is a cat. It is highly likely that if 'Greg is a swan' or 'Lily is a lion' or both then John dropped the apple. We believe that if 'Gertrude is a cat' or 'Lily is a lion' or both then Brian is green. It is almost certain that if 'Greg is a swan' or 'Lily is a lion' or both then Mary got the milk.
It is likely that 'Gertrude is a cat and Lily is a lion'.
It is highly unlikely that 'Gertrude is a cat and Lily is a lion'.
It is likely that 'Gertrude is a cat and Lily is a lion'.

  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.
  0.2::factB.
  0.2::factC.
  %hop1
  0.9::factX:-or(factA,factB).
  0.75::factY:-or(factC,factB).
  0.95::factZ:-or(factA,factB).

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

  query(conclusion).
  
'Gertrude is a cat and Lily is a lion'.