context: We doubt that Lily is a frog. It is probable that Julius is white. We doubt that Sandra took the football.
hypothesis: Chances are slight that 'Julius is white and Lily is a frog'.
valid_hypothesis: Chances are slight that 'Julius is white and Lily is a frog'.
invalid_hypothesis: There is a better than even chance that 'Julius is white and Lily is a frog'.
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.
    0.7::factB.
    0.2::factC.
    
  
    %hop2
    conclusion:-and(factB,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Julius is white and Lily is a frog'.