context: It is improbable that Emily is a cat. It is probably not the case that John went to the hallway. It is impossible that Greg is a frog. We doubt that if either 'Emily is a cat' or 'Greg is a frog' but not both then Winona is a wolf. It is probably the case that if 'Greg is a frog' or 'Emily is a cat' or both then Mary moved to the office. It is likely that if 'Emily is a cat' or 'Greg is a frog' or both then Lily is a rhino.
hypothesis: There is a better than even chance that either 'Greg is a frog' or 'Winona is a wolf' but not both.
valid_hypothesis: There is almost no chance that either 'Greg is a frog' or 'Winona is a wolf' but not both.
invalid_hypothesis: There is a better than even chance that either 'Greg is a frog' or 'Winona is a wolf' 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.
    0.25::factB.
    0.0::factC.
    %hop1
    0.2::factX:-xor(factA,factC).
    0.7::factY:-or(factC,factA).
    0.7::factZ:-or(factA,factC).
  
    %hop2
    conclusion:-xor(factC,factX).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Greg is a frog' or 'Winona is a wolf' but not both.