context: Chances are about even that John took the milk. It is improbable that Greg is a swan. It is highly unlikely that Brian is white.
hypothesis: There is a better than even chance that greg is a swan, and Brian is white.
valid_hypothesis: It is impossible that greg is a swan, and Brian is white.
invalid_hypothesis: There is a better than even chance that greg is a swan, and Brian is white.
hypothesis_assertion: Greg is a swan, and Brian is white.