The fourth essay in “Zombies, Vampires and Philosophy” is “Dead Serious: Evil and the Ontology of the Undead” by Manuel Vargas. In it, he asks whether we ought to consider the undead as being necessarily evil, and wraps that around a consideration of what it means to be “undead” anyway. He does this by talking about the difference between a natural kind and a nominal kind, and concludes that the undead are not a natural kind, but are instead a kind generated by a loose classification or generalization. So, then, what would it mean to say that the undead are, in fact, a natural kind?
Well, a natural kind is usually seen to be a kind carved out by nature, where we classify things based on real distinctions between them and thus form real and true categories. What is important about natural kinds is that we can say that they are the correct classification for the concept that we’re talking about. For example, it is often believed that “mammals” and “fish” represent natural kinds, and so it is correct to classify whales as mammals and not as fish. On the other hand, if we were dealing with a nominal kind, then it’s just a matter of convenience whether whales are fish or are mammals, and you can’t say that someone who says that whales are fish is, in fact, wrong.
Thus, to suggest that the undead is just or even something like a nominal kind is essentially to say that there isn’t really a right answer to the question of whether a particular thing — not merely something with the same name as some other thing — is really undead or not. The problem is that “undead” seems to indicate a third category that could be said to be “between” the categories of “living” and “dead”. We certainly think that the classifications of “living” and “dead” are natural kinds, and we have no reason to think that they aren’t. If they are, then “undead” must also be a natural kind. Vargas challenges this generally by pointing out all sorts of gray area cases, like supernatural vs natural zombies and people who have been resurrected from the dead (Lazarus, for example) to say that it doesn’t look like there’s a clear conceptual division between the undead and the living or the dead, and so it is more like a nominal kind where we classify things just for convenience. The problem is that as an intermediate category, “undead” is going to be a more complicated classification, but that doesn’t mean that it isn’t a clear conceptual category. Some of the examples that he gives of problem cases might well turn out to be things that we shouldn’t call “undead” at all. In the case of zombies, we can see that we might have to classify the undead into subcategories of “supernatural undead” and “natural undead” … or, perhaps, we don’t, and all “undead” are supernatural and any natural “undead” creature should really be considered to be still alive. Also, people resurrected from the dead, in general, are considered to be alive, as demonstrated by the “Resurrection” type spells in AD&D which clearly result in people that are conceptually still alive, as opposed to the spells that produce undead creatures. So Vargas does not have enough evidence to say that “undead” does not reflect a natural kind.
And assuming that they are a natural kind actually gives us an easier way to get to Vargas’ final point, which is that we can’t call the “undead” evil. If “undead” reflects a natural kind, then it has a well-defined set of conceptual properties that all member of the category must have, even if they are not the only category that has one or more of those properties. For example, it is generally considered to be a defining conceptual property of mammals that they give birth to live young. This does not mean that anything that gives birth to live young is necessarily a mammal, but it will be an exceptionally rare mammal that doesn’t give birth to live young. Thus, if we want to say that all “undead” are necessarily evil, it will have to be that being evil is a conceptual property in the same way as “gives birth of live young” is for mammals, which means that if the “undead” isn’t evil, we will have good a priori reason to doubt that it is really “undead”. This means that conceiving of an “undead” that is not evil should be exceptionally difficult, and always look like a strong conceptual contradiction, and not just something that we don’t see often. I agree with his analysis of what we usually think of as evil, and then point out that it is trivially easy — as he himself demonstrates — to conceive of “undead” that don’t count as evil. Zombies might not have the mental ability to be evil, any more than the aliens in Alien count as actually evil, and we have seen lots of examples of vampires that try to do good. Thus, being evil is not a conceptual property of “undead” because we can easily conceive of “undead” that are not evil and only not that they are rare, not that they are therefore not really “undead”.
So, if we think of “undead” as a natural kind, we can see that it isn’t a defining or necessary quality of the “undead” that they be evil. This means that we are indeed wrong to think of the “undead” as being necessarily evil. That does not mean, however, that we shouldn’t assume that they are until we have reason to think that they aren’t evil, as it might be a common instance property of the “undead” … but isn’t a conceptual property of “undead”.