context: It is likely that Mary left the apple. Chances are slight that Brian is a swan. We doubt that Daniel took the milk. It is highly unlikely that if Mary left the apple, or Daniel took the milk, then Lily is white. We doubt that if either Daniel took the milk, or Mary left the apple, then Julius is gray. Chances are about even that if Mary left the apple, and Daniel took the milk, then John went to the kitchen.
hypothesis: It is probably the case that either Mary left the apple, or Brian is a swan.
valid_hypothesis: It is probably the case that either Mary left the apple, or Brian is a swan.
invalid_hypothesis: It is highly unlikely that either Mary left the apple, or Brian is a swan.
hypothesis_assertion: Either Mary left the apple, or Brian is a swan.