It is highly likely that Fred discarded the apple. We doubt that Brian is a rhino. It is highly unlikely that Julius is green. It is probably the case that if either 'Fred discarded the apple' or 'Brian is a rhino' but not both then Gertrude is a wolf. It is likely that if 'Brian is a rhino and Julius is green' then Mary grabbed the milk. It is unlikely that if 'Julius is green' or 'Fred discarded the apple' or both then Bernhard is a swan.
It is highly unlikely that 'Bernhard is a swan and Brian is a rhino'.
It is highly unlikely that 'Bernhard is a swan and Brian is a rhino'.
It is almost certain that 'Bernhard is a swan and Brian is a rhino'.

  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
  0.9::factA.
  0.2::factB.
  0.05::factC.
  %hop1
  0.7::factX:-xor(factA,factB).
  0.7::factY:-and(factB,factC).
  0.2::factZ:-or(factC,factA).

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

  query(conclusion).
  
'Bernhard is a swan and Brian is a rhino'.