context: It is improbable that Greg is a frog. It is improbable that Fred dropped the milk. Chances are about even that Julius is a frog.
hypothesis: There is a better than even chance that 'Julius is a frog' or 'Fred dropped the milk' or both.
valid_hypothesis: There is a better than even chance that 'Julius is a frog' or 'Fred dropped the milk' or both.
invalid_hypothesis: It is impossible that 'Julius is a frog' or 'Fred dropped the milk' or both.
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
    0.1::factA.
    0.1::factB.
    0.5::factC.
    
  
    %hop2
    conclusion:-or(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Julius is a frog' or 'Fred dropped the milk' or both.