context: We believe that Winona is a cat. There is a better than even chance that Mary left the football. It is probably the case that Brian is yellow.
hypothesis: Chances are about even that either 'Mary left the football' or 'Winona is a cat' but not both.
valid_hypothesis: Chances are about even that either 'Mary left the football' or 'Winona is a cat' but not both.
invalid_hypothesis: There is almost no chance that either 'Mary left the football' or 'Winona is a cat' 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
    0.75::factA.
    0.6::factB.
    0.7::factC.
    
  
    %hop2
    conclusion:-xor(factB,factA).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Mary left the football' or 'Winona is a cat' but not both.