context: It is impossible that Julius is a swan. It is probably the case that Mary left the football. It is impossible that Jason is bored.
hypothesis: It is impossible that mary left the football, and Julius is a swan.
valid_hypothesis: It is impossible that mary left the football, and Julius is a swan.
invalid_hypothesis: There is a better than even chance that mary left the football, and Julius is a swan.
hypothesis_assertion: Mary left the football, and Julius is a swan.