We doubt that Brian is white. It is almost certain that John discarded the apple. Chances are slight that Lily is a swan. We doubt that if 'Lily is a swan and John discarded the apple' then Mary took the football. It is improbable that if 'Brian is white' or 'Lily is a swan' or both then Bernhard is yellow. It is probably not the case that if 'Brian is white' or 'John discarded the apple' or both then Winona is a mouse.
It is likely that 'Bernhard is yellow' or 'Lily is a swan' or both.
It is improbable that 'Bernhard is yellow' or 'Lily is a swan' or both.
It is likely that 'Bernhard is yellow' or 'Lily is a swan' 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
  0.2::factA.
  0.95::factB.
  0.1::factC.
  %hop1
  0.2::factX:-and(factC,factB).
  0.1::factY:-or(factA,factC).
  0.25::factZ:-or(factA,factB).

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

  query(conclusion).
  
'Bernhard is yellow' or 'Lily is a swan' or both.