It is highly unlikely that Jason is tired. We doubt that Julius is a frog. We believe that John left the milk. It is almost certain that if either 'Jason is tired' or 'Julius is a frog' but not both then Greg is gray. It is impossible that if either 'Julius is a frog' or 'Jason is tired' but not both then Lily is a swan. It is impossible that if 'Jason is tired' or 'Julius is a frog' or both then Mary went to the bedroom.
It is probable that 'Lily is a swan' or 'Jason is tired' or both.
It is highly unlikely that 'Lily is a swan' or 'Jason is tired' or both.
It is probable that 'Lily is a swan' or 'Jason is tired' 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
  0.05::factA.
  0.2::factB.
  0.75::factC.
  %hop1
  0.95::factX:-xor(factA,factB).
  0.0::factY:-xor(factB,factA).
  0.0::factZ:-or(factA,factB).

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

  query(conclusion).
  
'Lily is a swan' or 'Jason is tired' or both.