context: We doubt that Winona is a sheep. It is likely that Julius is a frog. Chances are about even that Greg is white.
hypothesis: Chances are slight that 'Winona is a sheep and Julius is a frog'.
valid_hypothesis: Chances are slight that 'Winona is a sheep and Julius is a frog'.
invalid_hypothesis: It is certain that 'Winona is a sheep and Julius 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.
    0.5::factC.
    
  
    %hop2
    conclusion:-and(factA,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Winona is a sheep and Julius is a frog'.