Now, it appears that the preceding view may be opposed by certain arguments.
 Each thing is specified by its own specific difference. But evil is a specific difference in some genera; for instance, among habits and acts in the moral order. just as virtue is specifically a good habit, so is the contrary vice specifically a bad habit. The same may be said of virtuous and vicious acts. Therefore, evil is that which gives specificity to some things, and thus it is an essence and is natural to certain things.
 Again, of two contraries, each is a definite nature, for, if one contrary were supposed to be nothing, then it would be either a privation or a pure negation. But good and evil are said to be contraries. Therefore, evil is a nature of some sort.
 Besides, good and evil are spoken of by Aristotle in the Categories [8: 14a 24] as “genera of contraries.” Now, there is an essence and a definite nature for each kind of genus. There are no species or differences for non-being; so, that which does not exist cannot be a genus. Therefore, evil is a definite essence and nature.
 Moreover, everything that acts is a real thing. Now, evil does act precisely as evil, for it attacks the good and corrupts it. So, evil precisely as evil is a real thing.
 Furthermore, wherever the distinction of more or less is found, there must be certain things arranged in hierarchic order, since neither negations nor privations admit of more or less. But among evils, one may be worse than another. It would seem, then, that evil must be a real thing.
 Again, thing and being are convertible. There is evil in the world. Therefore, it is a real thing and a nature.
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