The Concept of a Zombie
(Or: On the Postmortem Survival of Conceptual Analysis)
It goes without saying that the recent outbreak of brain-eating corpses has been injurious to social order. But in addition to inspiring fear and panic in the man on the street, zombies have proved to be a source of headache for philosophers. For them it is apparently not enough to threaten our lives; no, they must call our concept of life itself into question. (And we thought phenomenal zombies were bad!)
Four positions jointly exhaust the logical possibilities, and they have all found adherents in the literature. One could think that zombies are (1) alive, (2) dead, (3) both, or (4) neither. In the remainder of this survey I will canvass each of these possibilities, and present some of the considerations that have been adduced for and against them.
Bioticists hold that zombies are (only) alive. Admittedly, they are not paradigm examples of living things, but neither are tomatoes paradigm examples of fruit, and yet by any reasonable biological criterion that is exactly what they are. Analogously, bioticists argue, zombies satisfy the biological criteria for life: They consume nutrients (neurons and glia; i.e. brains), they can move, they reproduce (asexually, through biting), giving rise to “fertile offspring” (zombies who originate through biting can themselves bite people and create other zombies), and some of their cells can multiply, so they can heal themselves to a limited extent—military research has shown that the glia zombies consume are integrated into their nervous systems, while the neurons provide the raw material to repair the zombies’ neurons, or even grow new ones. Moreover, bioticists claim, it just seems intuitively obvious that zombies are alive—it’s hard to deny, when being chased by a walking, groaning, to some extent intelligent neurovore that one is being stalked by a living thing. And one can’t leave out the linguistic evidence: When we shoot one in the head, electrocute it, or burn it to ash, we do most often say that we’ve killed it. Now, bioticists will say, it is surely conceptually impossible to kill something that isn’t alive; so, since it is part of our folk theory of zombies that we can kill them, it must be part of our folk theory of zombies that they are alive. That zombies are alive is thus part of common sense—and while common sense cannot be a satisfactory place at which to stop, it can hardly be a bad place from which to start.
Abioticists—or “dead-heads,” as they affectionately refer to one another—maintain that zombies are (only) dead. Abioticists admit that there is some (slight) linguistic evidence to regard zombies as living, but insist that on the whole common sense and science are against the idea. They are quick to point out that all zombies have died at some point—a trait shared by all clear cases of dead things! The mere fact that they have regained some bodily functions is not enough to make them alive again. Also, many zombies—all but the freshest—are in various stages of decay, another trait shared by all clear cases of dead things. Furthermore, zombies do not need to breathe, and for many of them their circulatory systems don’t even work, neither of which holds for any clear case of a living being that has a circulatory system.
In addition, Abioticists question how well zombies really satisfy the biological criteria for life. Sure enough—and unfortunately enough!—they move and consume nutrients, but the multiplication of their cells is partial at best, being restricted almost entirely to the nervous system. But most importantly, dead-heads maintain, zombies do not truly reproduce—the zombies that they “sire” are not new organisms at all, but rather pre-existing ones who die and become zombies themselves. Even viruses, when they reproduce, generate new copies of themselves, and biologists do not regard them as being alive. Finally, while zombies do sire other zombies, there is nothing like the inheritance of traits trough genetics or their alteration through evolution that typifies all known living organisms, a point frequently glossed over by bioticists. A hundred generations from now, zombies will not be any better at hunting for brains than their ancestors of today—and thank God for that!
For zombie dual-aspect theorists—“zombie dualists,” or “zualists” for short—the term ‘living dead’ is not the oxymoron it may appear to be. Zualists think they can have the best of both worlds—zombies share many features with living things, and also with dead ones; hence, they are best regarded as both alive and dead. Unlike bioticists and Abioticists, zualists think they can account for all of the intuitions that underwrite our folk theory of zombies: Zombies are alive, which explains how it is conceptually possible for them to be killed. Nevertheless, they are also dead, which explains how it is conceptually possible for them to have died and to exhibit different stages of decay. And the fact that they satisfy some of the biological criteria for life while ambiguously satisfying others fits well with the idea that zombies are both alive and dead. Finally, the very popularity of the term ‘living dead’ bears witness, they claim, to the fact that the folk do not regard the concepts of life and death as incompatible.
Bioticists and Abioticists alike greet zualism with a stare as incredulous as the one received by those who first reported that corpses were rising from their graves. It seems just obvious to them that life and death exclude each other, just as red and green or motion and rest do. (This is especially so for those who hold the increasingly popular deflationary theory of death—that to be dead is simply not to be alive.) And it is not as though we have biological criteria for being alive and biological criteria for being dead, and that zombies satisfy both. It seems rather that we have only biological criteria for being alive, and that it is unclear whether zombies satisfy them. And the popularity of the term ‘living dead’ shows little, if anything—people often respond to questions with “yes and no,” but would anyone regard that as a good reason to think that the folk are committed to dialetheism, let alone that it is true?
Last, but not necessarily least, we have the undeadites, who regard zombies as neither living nor dead. Undeadites agree with dead-heads that zombies do not fit the criteria for being alive very well; and like both dead-heads and bioticists, they have the intuition that nothing could be both alive and dead. However, undeadites share the bioticists feeling that it seems somehow wrong to think that anything capable of chasing you, catching you and eating your brain could be dead in the usual sense. They accordingly propose to reject the deflationary theory of death and hold zombies to have a third status, which they call ‘undead’. Like logical theories that posit a third truth-value, this view has not found much acceptance among mainstream philosophers. If anything is neither alive nor dead, it would seem to be natural objects like rocks or man-made artifacts like toasters, but most would not think of them as being “undead.” Or, to put the point more neutrally, most would not place them in the same category as a zombie. The problem is that while rocks and toasters have no relevant features in common with living things or with dead ones, zombies seem to have some of both.
It is my hope that you now have a better appreciation for the various views on the concept of a zombie. The dispute between bioticists, dead-heads, zualists and undeadites remains as lively as ever (please forgive the pun!), and will not be adjudicated anytime soon. If the past century has taught us anything, it is that conceptual analysis is hard. Nonetheless, I remain hopeful that we will have made some progress in analyzing this concept before its tokens overrun us, should that fateful day ever come!