context: It is likely that Jeff discarded the apple. It is certain that Brian is gray. It is probable that Winona is a cat. Chances are about even that if Winona is a cat, and Brian is gray, then Julius is green. We doubt that if Jeff discarded the apple, and Brian is gray, then Bernhard is a rhino. There is almost no chance that if Brian is gray, and Winona is a cat, then Mary grabbed the milk.
hypothesis: There is little chance that either Mary grabbed the milk, or Brian is gray.
valid_hypothesis: It is certain that either Mary grabbed the milk, or Brian is gray.
invalid_hypothesis: There is little chance that either Mary grabbed the milk, or Brian is gray.
hypothesis_assertion: Either Mary grabbed the milk, or Brian is gray.