context: It is likely that Greg is a swan. It is highly likely that Sandra got the football. There is almost no chance that John grabbed the apple.
hypothesis: Chances are slight that 'John grabbed the apple' or 'Sandra got the football' or both.
valid_hypothesis: It is highly likely that 'John grabbed the apple' or 'Sandra got the football' or both.
invalid_hypothesis: Chances are slight that 'John grabbed the apple' or 'Sandra got 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
    0.7::factA.
    0.9::factB.
    0.02::factC.
    
  
    %hop2
    conclusion:-or(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'John grabbed the apple' or 'Sandra got the football' or both.