Chances are slight that Greg is yellow. It is unlikely that Winona is a sheep. It is probable that Bernhard is a swan. It is impossible that if 'Bernhard is a swan and Greg is yellow' then Lily is green. It is almost certain that if 'Bernhard is a swan and Greg is yellow' then Antoine is thirsty. It is probably the case that if either 'Winona is a sheep' or 'Bernhard is a swan' but not both then John got the milk.
It is probably not the case that 'Winona is a sheep' or 'Antoine is thirsty' or both.
It is probably not the case that 'Winona is a sheep' or 'Antoine is thirsty' or both.
It is almost certain that 'Winona is a sheep' or 'Antoine is thirsty' 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.
  0.2::factB.
  0.7::factC.
  %hop1
  0.0::factX:-and(factC,factA).
  0.95::factY:-and(factC,factA).
  0.7::factZ:-xor(factB,factC).

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

  query(conclusion).
  
'Winona is a sheep' or 'Antoine is thirsty' or both.