Chances are slight that Brian is a swan. We believe that Jessica is a mouse. It is almost certain that Gertrude is a cat. It is almost certain that if 'Gertrude is a cat' or 'Jessica is a mouse' or both then Lily is a frog. There is almost no chance that if either 'Brian is a swan' or 'Jessica is a mouse' but not both then Mary went to the bedroom. It is improbable that if 'Gertrude is a cat' or 'Jessica is a mouse' or both then Sandra grabbed the apple.
We believe that 'Jessica is a mouse' or 'Mary went to the bedroom' or both.
We believe that 'Jessica is a mouse' or 'Mary went to the bedroom' or both.
We doubt that 'Jessica is a mouse' or 'Mary went to the bedroom' 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
  0.1::factA.
  0.75::factB.
  0.95::factC.
  %hop1
  0.95::factX:-or(factC,factB).
  0.02::factY:-xor(factA,factB).
  0.1::factZ:-or(factC,factB).

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

  query(conclusion).
  
'Jessica is a mouse' or 'Mary went to the bedroom' or both.