context: Chances are about even that Bernhard is a swan. Chances are about even that Greg is yellow. It is certain that Brian is a lion.
hypothesis: It is impossible that brian is a lion, and Greg is yellow.
valid_hypothesis: Chances are about even that brian is a lion, and Greg is yellow.
invalid_hypothesis: It is impossible that brian is a lion, and Greg is yellow.
hypothesis_assertion: Brian is a lion, and Greg is yellow.