context: There is a better than even chance that Mary left the milk. It is certain that John grabbed the milk. It is impossible that Fred went to the bedroom.
hypothesis: It is impossible that fred went to the bedroom, and John grabbed the milk.
valid_hypothesis: It is impossible that fred went to the bedroom, and John grabbed the milk.
invalid_hypothesis: Chances are about even that fred went to the bedroom, and John grabbed the milk.
hypothesis_assertion: Fred went to the bedroom, and John grabbed the milk.