context: Chances are about even that Brian is a swan. Chances are slight that Mary went to the garden. It is probably the case that Lily is a frog.
hypothesis: Chances are about even that either Mary went to the garden, or Brian is a swan.
valid_hypothesis: Chances are about even that either Mary went to the garden, or Brian is a swan.
invalid_hypothesis: It is impossible that either Mary went to the garden, or Brian is a swan.
hypothesis_assertion: Either Mary went to the garden, or Brian is a swan.