context: It is probably not the case that Julius is a frog. Chances are slight that John left the apple. It is almost certain that Sandra took the apple. It is almost certain that if John left the apple, and Sandra took the apple, then Greg is a swan. There is a very good chance that if Julius is a frog, and Sandra took the apple, then Mary grabbed the milk. It is highly unlikely that if Julius is a frog, and Sandra took the apple, then Jeff discarded the milk.
hypothesis: It is probably not the case that either Mary grabbed the milk, or John left the apple.
valid_hypothesis: It is probably not the case that either Mary grabbed the milk, or John left the apple.
invalid_hypothesis: It is certain that either Mary grabbed the milk, or John left the apple.
hypothesis_assertion: Either Mary grabbed the milk, or John left the apple.