context: It is probably not the case that Jeff went to the garden. It is probably not the case that Lily is gray. It is unlikely that Gertrude is a mouse. It is improbable that if 'Gertrude is a mouse' or 'Lily is gray' or both then Bernhard is a swan. There is little chance that if 'Jeff went to the garden and Lily is gray' then John moved to the office. It is likely that if either 'Gertrude is a mouse' or 'Lily is gray' but not both then Julius is a lion.
hypothesis: It is likely that either 'Bernhard is a swan' or 'Gertrude is a mouse' but not both.
valid_hypothesis: It is unlikely that either 'Bernhard is a swan' or 'Gertrude is a mouse' but not both.
invalid_hypothesis: It is likely that either 'Bernhard is a swan' or 'Gertrude is a mouse' 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
    0.25::factA.
    0.25::factB.
    0.2::factC.
    %hop1
    0.1::factX:-or(factC,factB).
    0.1::factY:-and(factA,factB).
    0.7::factZ:-xor(factC,factB).
  
    %hop2
    conclusion:-xor(factX,factC).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Bernhard is a swan' or 'Gertrude is a mouse' but not both.