context: Chances are about even that John got the apple. We believe that Mary is in the bathroom. It is certain that Greg is a rhino.
hypothesis: It is highly likely that 'Mary is in the bathroom' or 'John got the apple' or both.
valid_hypothesis: It is highly likely that 'Mary is in the bathroom' or 'John got the apple' or both.
invalid_hypothesis: There is little chance that 'Mary is in the bathroom' or 'John got the apple' 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.
    0.75::factB.
    1.0::factC.
    
  
    %hop2
    conclusion:-or(factB,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Mary is in the bathroom' or 'John got the apple' or both.