context: It is likely that Greg is a swan. It is probably not the case that Julius is a frog. Chances are about even that Mary went to the bedroom. There is little chance that if Julius is a frog, and Greg is a swan, then Sandra put down the milk. We doubt that if Julius is a frog, or Greg is a swan, then Brian is green. It is unlikely that if Julius is a frog, and Greg is a swan, then Lily is a rhino.
hypothesis: Chances are about even that either Mary went to the bedroom, or Sandra put down the milk.
valid_hypothesis: Chances are about even that either Mary went to the bedroom, or Sandra put down the milk.
invalid_hypothesis: It is highly unlikely that either Mary went to the bedroom, or Sandra put down the milk.
hypothesis_assertion: Either Mary went to the bedroom, or Sandra put down the milk.