context: Chances are slight that Brian is a swan. It is almost certain that John discarded the milk. It is highly likely that Sumit is thirsty. There is a better than even chance that if either Sumit is thirsty, or Brian is a swan, then Gertrude is a mouse. There is almost no chance that if John discarded the milk, or Sumit is thirsty, then Mary went to the office. There is a very good chance that if Brian is a swan, or John discarded the milk, then Bernhard is white.
hypothesis: It is impossible that brian is a swan, and Gertrude is a mouse.
valid_hypothesis: It is impossible that brian is a swan, and Gertrude is a mouse.
invalid_hypothesis: It is certain that brian is a swan, and Gertrude is a mouse.
hypothesis_assertion: Brian is a swan, and Gertrude is a mouse.