context: There is a very good chance that Lily is white. Chances are slight that Sandra took the apple. There is a very good chance that John dropped the milk. We believe that if either 'John dropped the milk' or 'Lily is white' but not both then Bernhard is green. It is probably the case that if 'John dropped the milk' or 'Lily is white' or both then Julius is a rhino. There is almost no chance that if 'John dropped the milk and Sandra took the apple' then Brian is gray.
hypothesis: Chances are slight that 'Lily is white and John dropped the milk'.
valid_hypothesis: There is a better than even chance that 'Lily is white and John dropped the milk'.
invalid_hypothesis: Chances are slight that 'Lily is white and John dropped the milk'.
problog: 
    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
    0.8::factA.
    0.1::factB.
    0.8::factC.
    %hop1
    0.75::factX:-xor(factC,factA).
    0.7::factY:-or(factC,factA).
    0.02::factZ:-and(factC,factB).
  
    %hop2
    conclusion:-and(factA,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Lily is white and John dropped the milk'.