context: It is improbable that Greg is a swan. It is likely that Mary went to the kitchen. It is probably not the case that Sandra got the apple. Chances are about even that if Sandra got the apple, or Greg is a swan, then Bernhard is a rhino. There is a better than even chance that if Sandra got the apple, and Greg is a swan, then Brian is a frog. There is a very good chance that if Greg is a swan, and Mary went to the kitchen, then Lily is a lion.
hypothesis: There is a very good chance that either Greg is a swan, or Brian is a frog.
valid_hypothesis: Chances are slight that either Greg is a swan, or Brian is a frog.
invalid_hypothesis: There is a very good chance that either Greg is a swan, or Brian is a frog.
hypothesis_assertion: Either Greg is a swan, or Brian is a frog.