It is unlikely that Lily is yellow. It is probably the case that Julius is green. It is unlikely that Fred dropped the milk. There is a better than even chance that if either 'Lily is yellow' or 'Julius is green' but not both then John put down the apple. We believe that if 'Julius is green' or 'Lily is yellow' or both then Greg is gray. It is impossible that if 'Julius is green' or 'Fred dropped the milk' or both then Brian is a lion.
Chances are about even that 'John put down the apple' or 'Lily is yellow' or both.
Chances are about even that 'John put down the apple' or 'Lily is yellow' or both.
It is impossible that 'John put down the apple' or 'Lily is yellow' 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.
  0.7::factB.
  0.2::factC.
  %hop1
  0.6::factX:-xor(factA,factB).
  0.75::factY:-or(factB,factA).
  0.0::factZ:-or(factB,factC).

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

  query(conclusion).
  
'John put down the apple' or 'Lily is yellow' or both.