There is a better than even chance that Lily is yellow. It is probably the case that Mary left the football. It is unlikely that Greg is a swan. We doubt that if either 'Greg is a swan' or 'Mary left the football' but not both then Jessica is a sheep. We doubt that if 'Mary left the football and Lily is yellow' then Bernhard is a frog. It is probably not the case that if 'Greg is a swan' or 'Mary left the football' or both then Fred went to the garden.
It is probable that 'Greg is a swan' or 'Bernhard is a frog' or both.
It is probably not the case that 'Greg is a swan' or 'Bernhard is a frog' or both.
It is probable that 'Greg is a swan' or 'Bernhard is a frog' 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
  0.6::factA.
  0.7::factB.
  0.2::factC.
  %hop1
  0.2::factX:-xor(factC,factB).
  0.2::factY:-and(factB,factA).
  0.25::factZ:-or(factC,factB).

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

  query(conclusion).
  
'Greg is a swan' or 'Bernhard is a frog' or both.