context: It is probably the case that Julius is a swan. There is little chance that John picked up the milk. It is unlikely that Mary left the apple. We doubt that if John picked up the milk, and Mary left the apple, then Emily is a mouse. It is likely that if either John picked up the milk, or Mary left the apple, then Brian is green. Chances are about even that if either Julius is a swan, or John picked up the milk, then Lily is a rhino.
hypothesis: It is highly unlikely that lily is a rhino, and Mary left the apple.
valid_hypothesis: It is highly unlikely that lily is a rhino, and Mary left the apple.
invalid_hypothesis: We believe that lily is a rhino, and Mary left the apple.
hypothesis_assertion: Lily is a rhino, and Mary left the apple.