context: It is probably not the case that Brian is a swan. There is a better than even chance that Sandra took the milk. It is impossible that Lily is a rhino. It is almost certain that if either Sandra took the milk, or Lily is a rhino, then Jason is bored. We doubt that if Lily is a rhino, or Sandra took the milk, then Bill is in the school. There is a very good chance that if Brian is a swan, or Sandra took the milk, then John discarded the apple.
hypothesis: It is improbable that sandra took the milk, and Brian is a swan.
valid_hypothesis: It is improbable that sandra took the milk, and Brian is a swan.
invalid_hypothesis: It is certain that sandra took the milk, and Brian is a swan.
hypothesis_assertion: Sandra took the milk, and Brian is a swan.