context: It is highly unlikely that Jeff dropped the apple. There is almost no chance that Mary took the football. Chances are slight that Julius is a swan.
hypothesis: There is little chance that 'Julius is a swan' or 'Mary took the football' or both.
valid_hypothesis: There is little chance that 'Julius is a swan' or 'Mary took the football' or both.
invalid_hypothesis: There is a better than even chance that 'Julius is a swan' or 'Mary took the football' 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
    0.05::factA.
    0.02::factB.
    0.1::factC.
    
  
    %hop2
    conclusion:-or(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Julius is a swan' or 'Mary took the football' or both.