context: Chances are slight that Lily is a swan. It is probably the case that John picked up the apple. It is almost certain that Mary left the football.
hypothesis: Chances are slight that either 'Mary left the football' or 'Lily is a swan' but not both.
valid_hypothesis: It is highly likely that either 'Mary left the football' or 'Lily is a swan' but not both.
invalid_hypothesis: Chances are slight that either 'Mary left the football' or 'Lily is a swan' 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
    0.1::factA.
    0.7::factB.
    0.95::factC.
    
  
    %hop2
    conclusion:-xor(factC,factA).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Mary left the football' or 'Lily is a swan' but not both.