context: Chances are about even that Daniel got the football. It is probably the case that Mary went to the office. It is almost certain that John put down the apple.
hypothesis: Chances are about even that either 'John put down the apple' or 'Daniel got the football' but not both.
valid_hypothesis: Chances are about even that either 'John put down the apple' or 'Daniel got the football' but not both.
invalid_hypothesis: There is almost no chance that either 'John put down the apple' or 'Daniel got the football' 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.
    0.7::factB.
    0.95::factC.
    
  
    %hop2
    conclusion:-xor(factC,factA).
  
    query(conclusion).
    
hypothesis_assertion: Either 'John put down the apple' or 'Daniel got the football' but not both.