context: It is highly likely that Lily is a lion. It is probably not the case that Daniel is in the garden. It is certain that Greg is a frog. Chances are about even that if either Lily is a lion, or Greg is a frog, then John left the football. We doubt that if Daniel is in the garden, and Greg is a frog, then Yann is thirsty. It is improbable that if Lily is a lion, and Greg is a frog, then Brian is yellow.
hypothesis: It is certain that either John left the football, or Brian is yellow.
valid_hypothesis: Chances are slight that either John left the football, or Brian is yellow.
invalid_hypothesis: It is certain that either John left the football, or Brian is yellow.
hypothesis_assertion: Either John left the football, or Brian is yellow.