context: It is likely that Julius is a lion. It is probably the case that Daniel got the apple. Chances are about even that John moved to the office. It is highly likely that if John moved to the office, and Julius is a lion, then Lily is green. It is unlikely that if either John moved to the office, or Daniel got the apple, then Brian is yellow. It is unlikely that if Julius is a lion, or John moved to the office, then Sandra grabbed the milk.
hypothesis: It is impossible that either Lily is green, or Brian is yellow.
valid_hypothesis: Chances are about even that either Lily is green, or Brian is yellow.
invalid_hypothesis: It is impossible that either Lily is green, or Brian is yellow.
hypothesis_assertion: Either Lily is green, or Brian is yellow.