context: It is certain that Greg is white. It is impossible that Brian is yellow. It is probable that Lily is a lion. It is probably not the case that if 'Lily is a lion' or 'Brian is yellow' or both then Jessica is a wolf. It is certain that if 'Greg is white' or 'Brian is yellow' or both then John got the milk. It is probably not the case that if 'Lily is a lion' or 'Brian is yellow' or both then Bernhard is a swan.
hypothesis: There is a very good chance that either 'Jessica is a wolf' or 'John got the milk' but not both.
valid_hypothesis: There is a very good chance that either 'Jessica is a wolf' or 'John got the milk' but not both.
invalid_hypothesis: It is improbable that either 'Jessica is a wolf' or 'John got the milk' 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
    1.0::factA.
    0.0::factB.
    0.7::factC.
    %hop1
    0.25::factX:-or(factC,factB).
    1.0::factY:-or(factA,factB).
    0.25::factZ:-or(factC,factB).
  
    %hop2
    conclusion:-xor(factX,factY).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Jessica is a wolf' or 'John got the milk' but not both.