context: Chances are about even that John moved to the garden. Chances are about even that Greg is white. There is a better than even chance that Sandra dropped the apple.
hypothesis: There is almost no chance that either 'Sandra dropped the apple' or 'John moved to the garden' but not both.
valid_hypothesis: Chances are about even that either 'Sandra dropped the apple' or 'John moved to the garden' but not both.
invalid_hypothesis: There is almost no chance that either 'Sandra dropped the apple' or 'John moved to the garden' 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
    0.5::factA.
    0.5::factB.
    0.6::factC.
    
  
    %hop2
    conclusion:-xor(factC,factA).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Sandra dropped the apple' or 'John moved to the garden' but not both.