context: It is probable that Sandra got the milk. Chances are about even that Greg is a lion. We doubt that Mary put down the apple.
hypothesis: There is a very good chance that 'Sandra got the milk' or 'Greg is a lion' or both.
valid_hypothesis: There is a very good chance that 'Sandra got the milk' or 'Greg is a lion' or both.
invalid_hypothesis: It is improbable that 'Sandra got the milk' or 'Greg is a lion' 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.
    0.5::factB.
    0.2::factC.
    
  
    %hop2
    conclusion:-or(factA,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Sandra got the milk' or 'Greg is a lion' or both.