context: It is probably not the case that Winona is a wolf. Chances are slight that Mary went to the office. Chances are about even that Bernhard is white. We doubt that if Bernhard is white, or Winona is a wolf, then Greg is a rhino. We doubt that if either Winona is a wolf, or Bernhard is white, then Julius is white. There is little chance that if Mary went to the office, or Winona is a wolf, then John left the football.
hypothesis: It is impossible that john left the football, and Greg is a rhino.
valid_hypothesis: It is impossible that john left the football, and Greg is a rhino.
invalid_hypothesis: It is certain that john left the football, and Greg is a rhino.
hypothesis_assertion: John left the football, and Greg is a rhino.