context: It is almost certain that Mary left the apple. It is almost certain that John picked up the milk. It is almost certain that Fred is in the park. It is unlikely that if either Mary left the apple, or John picked up the milk, then Brian is a lion. It is highly unlikely that if Mary left the apple, or John picked up the milk, then Greg is a rhino. It is almost certain that if Mary left the apple, and Fred is in the park, then Bernhard is a rhino.
hypothesis: It is impossible that brian is a lion, and Greg is a rhino.
valid_hypothesis: It is impossible that brian is a lion, and Greg is a rhino.
invalid_hypothesis: There is a better than even chance that brian is a lion, and Greg is a rhino.
hypothesis_assertion: Brian is a lion, and Greg is a rhino.