 However, some of the other criteria do not clearly mark genera off from universal wholes. Consider, for example, the second criterion. Boethius seems to have something like this in mind when he articulates difference (b): the parts of a genus are dependent upon the genus, whereas the whole is dependent upon its parts. In other words, if there are no animals, there can be no dogs or humans. In contrast, the house depends upon its parts. If you take away the roof and floor, the house ceases to exist. But universal wholes seem to behave like genera, not houses. If we annihilate all individual humans, we do not eliminate the universal Human Being. Therefore, difference (b) does not cleanly demarcate genera from universal wholes.