context: Chances are about even that Julius is a swan. There is a very good chance that Brian is a frog. There is a better than even chance that Sandra left the football.
hypothesis: It is probably not the case that 'Brian is a frog' or 'Julius is a swan' or both.
valid_hypothesis: It is highly likely that 'Brian is a frog' or 'Julius is a swan' or both.
invalid_hypothesis: It is probably not the case that 'Brian is a frog' or 'Julius is a swan' 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
    0.5::factA.
    0.8::factB.
    0.6::factC.
    
  
    %hop2
    conclusion:-or(factB,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is a frog' or 'Julius is a swan' or both.