context: It is impossible that Bernhard is a swan. It is almost certain that Emily is a wolf. There is a better than even chance that John put down the milk.
hypothesis: Chances are slight that either 'Bernhard is a swan' or 'John put down the milk' but not both.
valid_hypothesis: There is a better than even chance that either 'Bernhard is a swan' or 'John put down the milk' but not both.
invalid_hypothesis: Chances are slight that either 'Bernhard is a swan' or 'John put down the milk' but not 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
    0.0::factA.
    0.95::factB.
    0.6::factC.
    
  
    %hop2
    conclusion:-xor(factA,factC).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Bernhard is a swan' or 'John put down the milk' but not both.