context: Chances are about even that John put down the milk. It is highly unlikely that Bernhard is a frog. There is almost no chance that Greg is a rhino.
hypothesis: It is highly likely that 'Greg is a rhino and Bernhard is a frog'.
valid_hypothesis: It is impossible that 'Greg is a rhino and Bernhard is a frog'.
invalid_hypothesis: It is highly likely that 'Greg is a rhino and Bernhard 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
    0.5::factA.
    0.05::factB.
    0.02::factC.
    
  
    %hop2
    conclusion:-and(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Greg is a rhino and Bernhard is a frog'.