context: It is highly unlikely that Jessica is a cat. There is a very good chance that Gertrude is a mouse. It is unlikely that John went to the hallway. Chances are about even that if 'John went to the hallway and Jessica is a cat' then Lily is yellow. It is highly unlikely that if either 'Jessica is a cat' or 'Gertrude is a mouse' but not both then Brian is a frog. There is almost no chance that if 'John went to the hallway' or 'Gertrude is a mouse' or both then Bernhard is white.
hypothesis: We doubt that 'Bernhard is white' or 'John went to the hallway' or both.
valid_hypothesis: We doubt that 'Bernhard is white' or 'John went to the hallway' or both.
invalid_hypothesis: It is almost certain that 'Bernhard is white' or 'John went to the hallway' or 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.
    0.8::factB.
    0.2::factC.
    %hop1
    0.5::factX:-and(factC,factA).
    0.05::factY:-xor(factA,factB).
    0.02::factZ:-or(factC,factB).
  
    %hop2
    conclusion:-or(factZ,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Bernhard is white' or 'John went to the hallway' or both.