context: It is highly unlikely that Julius is a swan. There is a very good chance that Greg is a lion. It is probably not the case that Julie is in the bedroom.
hypothesis: Chances are about even that julie is in the bedroom, and Julius is a swan.
valid_hypothesis: There is almost no chance that julie is in the bedroom, and Julius is a swan.
invalid_hypothesis: Chances are about even that julie is in the bedroom, and Julius is a swan.
hypothesis_assertion: Julie is in the bedroom, and Julius is a swan.