context: It is highly unlikely that Mary went to the bedroom. It is highly unlikely that Julius is white. It is likely that Bernhard is a swan. It is probable that if 'Bernhard is a swan' or 'Julius is white' or both then Jason is tired. It is highly likely that if 'Mary went to the bedroom and Julius is white' then Brian is a frog. It is improbable that if either 'Julius is white' or 'Mary went to the bedroom' but not both then Gertrude is a cat.
hypothesis: Chances are about even that either 'Gertrude is a cat' or 'Jason is tired' but not both.
valid_hypothesis: Chances are about even that either 'Gertrude is a cat' or 'Jason is tired' but not both.
invalid_hypothesis: It is impossible that either 'Gertrude is a cat' or 'Jason is tired' 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
    0.05::factA.
    0.05::factB.
    0.7::factC.
    %hop1
    0.7::factX:-or(factC,factB).
    0.9::factY:-and(factA,factB).
    0.1::factZ:-xor(factB,factA).
  
    %hop2
    conclusion:-xor(factZ,factX).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Gertrude is a cat' or 'Jason is tired' but not both.