context: It is probably the case that Winona is a mouse. It is impossible that Emily is a sheep. It is improbable that Julius is yellow. There is almost no chance that if 'Winona is a mouse and Emily is a sheep' then Mary went to the office. It is almost certain that if either 'Winona is a mouse' or 'Julius is yellow' but not both then John left the milk. Chances are slight that if 'Winona is a mouse' or 'Emily is a sheep' or both then Brian is gray.
hypothesis: It is improbable that either 'Winona is a mouse' or 'John left the milk' but not both.
valid_hypothesis: It is improbable that either 'Winona is a mouse' or 'John left the milk' but not both.
invalid_hypothesis: It is likely that either 'Winona is a mouse' or 'John left 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
    0.7::factA.
    0.0::factB.
    0.1::factC.
    %hop1
    0.02::factX:-and(factA,factB).
    0.95::factY:-xor(factA,factC).
    0.1::factZ:-or(factA,factB).
  
    %hop2
    conclusion:-xor(factA,factY).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Winona is a mouse' or 'John left the milk' but not both.