context: It is unlikely that Julius is a rhino. We doubt that Gertrude is a mouse. It is probable that Bernhard is a swan. It is improbable that if 'Gertrude is a mouse and Bernhard is a swan' then Mary moved to the garden. It is impossible that if either 'Bernhard is a swan' or 'Julius is a rhino' but not both then John went to the office. It is almost certain that if 'Julius is a rhino' or 'Bernhard is a swan' or both then Sandra left the football.
hypothesis: It is probable that either 'John went to the office' or 'Gertrude is a mouse' but not both.
valid_hypothesis: It is unlikely that either 'John went to the office' or 'Gertrude is a mouse' but not both.
invalid_hypothesis: It is probable that either 'John went to the office' 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
    0.2::factA.
    0.2::factB.
    0.7::factC.
    %hop1
    0.1::factX:-and(factB,factC).
    0.0::factY:-xor(factC,factA).
    0.95::factZ:-or(factA,factC).
  
    %hop2
    conclusion:-xor(factY,factB).
  
    query(conclusion).
    
hypothesis_assertion: Either 'John went to the office' or 'Gertrude is a mouse' but not both.