context: It is improbable that Lily is a lion. There is a very good chance that John went to the kitchen. It is probably not the case that Sandra left the football.
hypothesis: It is likely that either 'Sandra left the football' or 'John went to the kitchen' but not both.
valid_hypothesis: It is likely that either 'Sandra left the football' or 'John went to the kitchen' but not both.
invalid_hypothesis: It is impossible that either 'Sandra left the football' or 'John went to the kitchen' 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.
    0.8::factB.
    0.25::factC.
    
  
    %hop2
    conclusion:-xor(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Sandra left the football' or 'John went to the kitchen' but not both.