It is unlikely that Lily is yellow. We believe that Greg is a frog. We doubt that Bernhard is green. It is highly unlikely that if 'Greg is a frog' or 'Bernhard is green' or both then Mary picked up the milk. It is probably the case that if either 'Greg is a frog' or 'Lily is yellow' but not both then Julius is gray. Chances are slight that if 'Greg is a frog' or 'Bernhard is green' or both then John went to the kitchen.
It is probably the case that 'Julius is gray and Lily is yellow'.
It is highly unlikely that 'Julius is gray and Lily is yellow'.
It is probably the case that 'Julius is gray and Lily is yellow'.

  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.
  0.75::factB.
  0.2::factC.
  %hop1
  0.05::factX:-or(factB,factC).
  0.7::factY:-xor(factB,factA).
  0.1::factZ:-or(factB,factC).

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

  query(conclusion).
  
'Julius is gray and Lily is yellow'.