context: It is probably the case that John went to the garden. There is almost no chance that Greg is a frog. Chances are about even that Emily is a sheep. There is a better than even chance that if Emily is a sheep, and Greg is a frog, then Brian is a lion. There is a very good chance that if either John went to the garden, or Greg is a frog, then Sandra got the football. Chances are slight that if Greg is a frog, or Emily is a sheep, then Mary moved to the office.
hypothesis: It is highly unlikely that either Brian is a lion, or Emily is a sheep.
valid_hypothesis: Chances are about even that either Brian is a lion, or Emily is a sheep.
invalid_hypothesis: It is highly unlikely that either Brian is a lion, or Emily is a sheep.
hypothesis_assertion: Either Brian is a lion, or Emily is a sheep.