context: It is highly unlikely that Bill went to the hallway. We doubt that Gertrude is a cat. It is highly likely that Bernhard is yellow. It is probably the case that if Bernhard is yellow, and Bill went to the hallway, then Brian is a lion. Chances are about even that if either Gertrude is a cat, or Bill went to the hallway, then John discarded the apple. It is improbable that if Bernhard is yellow, and Bill went to the hallway, then Greg is a rhino.
hypothesis: It is impossible that greg is a rhino, and John discarded the apple.
valid_hypothesis: It is impossible that greg is a rhino, and John discarded the apple.
invalid_hypothesis: It is highly likely that greg is a rhino, and John discarded the apple.
hypothesis_assertion: Greg is a rhino, and John discarded the apple.