context: It is unlikely that Sandra dropped the milk. Chances are slight that Julius is a lion. There is a better than even chance that Greg is yellow. It is probably the case that if 'Sandra dropped the milk and Julius is a lion' then John got the apple. There is a better than even chance that if either 'Julius is a lion' or 'Greg is yellow' but not both then Bernhard is green. We doubt that if 'Sandra dropped the milk' or 'Julius is a lion' or both then Lily is yellow.
hypothesis: It is certain that 'Sandra dropped the milk and Julius is a lion'.
valid_hypothesis: There is almost no chance that 'Sandra dropped the milk and Julius is a lion'.
invalid_hypothesis: It is certain that 'Sandra dropped the milk and Julius is a lion'.
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
    0.2::factA.
    0.1::factB.
    0.6::factC.
    %hop1
    0.7::factX:-and(factA,factB).
    0.6::factY:-xor(factB,factC).
    0.2::factZ:-or(factA,factB).
  
    %hop2
    conclusion:-and(factA,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Sandra dropped the milk and Julius is a lion'.