context: It is almost certain that Mary picked up the apple. We believe that Brian is a frog. We doubt that John went to the garden.
hypothesis: There is almost no chance that 'Mary picked up the apple' or 'Brian is a frog' or both.
valid_hypothesis: It is certain that 'Mary picked up the apple' or 'Brian is a frog' or both.
invalid_hypothesis: There is almost no chance that 'Mary picked up the apple' or 'Brian is a frog' 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
    0.95::factA.
    0.75::factB.
    0.2::factC.
    
  
    %hop2
    conclusion:-or(factA,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Mary picked up the apple' or 'Brian is a frog' or both.