context: It is likely that Brian is a rhino. It is likely that Julius is a swan. We believe that Mary went to the kitchen. Chances are about even that if Mary went to the kitchen, or Brian is a rhino, then Lily is yellow. It is highly likely that if Brian is a rhino, or Mary went to the kitchen, then John grabbed the milk. It is impossible that if Mary went to the kitchen, and Brian is a rhino, then Fred is in the office.
hypothesis: It is probably not the case that either Brian is a rhino, or John grabbed the milk.
valid_hypothesis: It is probably not the case that either Brian is a rhino, or John grabbed the milk.
invalid_hypothesis: We believe that either Brian is a rhino, or John grabbed the milk.
hypothesis_assertion: Either Brian is a rhino, or John grabbed the milk.