context: It is certain that Sandra grabbed the milk. We believe that Brian is a swan. It is certain that Lily is a rhino. It is probably the case that if Sandra grabbed the milk, or Brian is a swan, then Fred is in the park. It is likely that if Sandra grabbed the milk, or Lily is a rhino, then Bernhard is a lion. It is highly unlikely that if either Lily is a rhino, or Brian is a swan, then Mary dropped the milk.
hypothesis: It is impossible that either Bernhard is a lion, or Fred is in the park.
valid_hypothesis: Chances are about even that either Bernhard is a lion, or Fred is in the park.
invalid_hypothesis: It is impossible that either Bernhard is a lion, or Fred is in the park.
hypothesis_assertion: Either Bernhard is a lion, or Fred is in the park.