context: Chances are slight that Bernhard is a swan. It is almost certain that Mary left the milk. It is probably the case that Fred went to the hallway. It is unlikely that if either Bernhard is a swan, or Fred went to the hallway, then Lily is a lion. Chances are about even that if Bernhard is a swan, or Fred went to the hallway, then Brian is white. We doubt that if either Mary left the milk, or Fred went to the hallway, then Julius is yellow.
hypothesis: It is probably not the case that fred went to the hallway, and Brian is white.
valid_hypothesis: It is probably not the case that fred went to the hallway, and Brian is white.
invalid_hypothesis: It is likely that fred went to the hallway, and Brian is white.
hypothesis_assertion: Fred went to the hallway, and Brian is white.