context: It is probably not the case that Julius is gray. It is almost certain that Greg is a swan. There is little chance that Lily is a rhino. Chances are about even that if Lily is a rhino, or Greg is a swan, then Mary went to the kitchen. It is highly unlikely that if either Julius is gray, or Greg is a swan, then Brian is white. Chances are slight that if either Greg is a swan, or Julius is gray, then Yann is thirsty.
hypothesis: It is highly unlikely that brian is white, and Greg is a swan.
valid_hypothesis: It is highly unlikely that brian is white, and Greg is a swan.
invalid_hypothesis: It is highly likely that brian is white, and Greg is a swan.
hypothesis_assertion: Brian is white, and Greg is a swan.