context: It is highly likely that John went to the hallway. It is probably not the case that Greg is a frog. Chances are about even that Brian is green. We doubt that if Greg is a frog, or Brian is green, then Sandra got the milk. There is little chance that if either Brian is green, or John went to the hallway, then Lily is a lion. There is a very good chance that if either John went to the hallway, or Greg is a frog, then Mary dropped the apple.
hypothesis: It is probably not the case that either John went to the hallway, or Sandra got the milk.
valid_hypothesis: There is a very good chance that either John went to the hallway, or Sandra got the milk.
invalid_hypothesis: It is probably not the case that either John went to the hallway, or Sandra got the milk.
hypothesis_assertion: Either John went to the hallway, or Sandra got the milk.