context: It is highly likely that Brian is a swan. Chances are slight that Greg is a frog. It is highly unlikely that Mary went to the bedroom.
hypothesis: We believe that 'Mary went to the bedroom' or 'Greg is a frog' or both.
valid_hypothesis: There is little chance that 'Mary went to the bedroom' or 'Greg is a frog' or both.
invalid_hypothesis: We believe that 'Mary went to the bedroom' or 'Greg is a frog' 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
    0.9::factA.
    0.1::factB.
    0.05::factC.
    
  
    %hop2
    conclusion:-or(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Mary went to the bedroom' or 'Greg is a frog' or both.