Image via Wikipedia
While George Romero introduced zombies to movie goers years ago, the fascination with the walking dead continues to grow like a zombie horde. While it is fun to watch the fictional zombies, it might be wondered whether or not the dead can really walk.
While “science” based zombies are standard zombies of most movies, there is also the classic supernatural zombie. These zombies are driven by supernatural forces rather than mysterious radiation or some sort of super virus. For example, the zombies I use in my Pathfinder campaigns are corpses that are possessed by unintelligent evil spirits of negative energy. Obviously, these zombies are make believe and are almost certainly not the sort of thing that could exist in this world. That said, if there is a supernatural aspect to this world (which seems rather unlikely) then supernatural zombies might be possible. I am, of course, inclined to think that they are not-mainly because of the lack of evidence.
As might be imagined, “science” based zombies would seem to have the best chance of being possible. It is also worth considering the possibility of what can be called a corpse suit. A corpse suit is a dead body that is “worn” by another living organism that moves it about, using it as protection or camouflage. Plants, insects and fungus have (in fiction, including several of my Call of Cthuhu adventures) been cast in such a role. While no known organism does this with human bodies, it does not seem like an impossibility. Of course, this sort of thing would not be a zombie in the strict sense. After all, the dead body is not walking itself but is being manipulated like a puppet.
One common cause of the “science” zombies is a virus or other such agent that re-animates (usually after killing). For example, my own Nightsiders (specifically “Dead Island”-not to be confused with the recent video game that uses the same name and basic plot) features a zombie agent that was being developed as a weapon. While an agent that causes people to act in zombie like ways certainly seems possible (as vividly portrayed in 28 Days Later), these people would not be zombies in the sense of being the walking dead for the obvious reason that they are not actually dead.
As might be imagined, the main challenge with creating the walking dead is getting a corpse to move under its own power. If the body is completely dead, then it would seem rather unlikely that it would be able to do so. After all, the dead nerve cells would not be able to direct the dead muscle cells to fire. Presumably the dead muscle cells could not fire, even if somehow signaled to do so by undead nerves.
One way around this, other than imagining some sort of undead cellular activity that is somehow not life (which might seem a bit supernatural), is to cheat a bit and allow for zombies that are partially alive. If parts of the brain, nervous system and muscles could remain alive (or were re-started after death) then a zombie of sorts would seem to be possible. After all, there could be enough neural guidance and muscle power left to move the mostly dead body around under its own power. This could, perhaps, be accomplished by a virus or bacteria that was rather selective.
Merely having a mobile mostly dead corpse would, of course, still not be quite enough. After all, the sort of zombie we are looking for does more than just lie on the table and twitch. It pursues the living and is presumably driven by an endless hunger for their brains.
Getting that sort of zombie seems rather tricky. After all the zombie would need enough mental functionality to be able to recognize and pursue the living yet be lacking enough so as to be a zombie (which are suppose to be unintelligent). The zombie would, of course, also need the motivation to hunt the living. Mere hunger would, of course, not be enough-otherwise zombies would just eat whatever they could find and would not be totally fixated on humans.
This challenge could be overcome by imagining that the agent that creates the zombie modifies the nervous system in such a way that the zombie behavior is created. There are, of course, diseases (such as rabies) that affect behavior and there are fungi that radically impact behavior (albeit primarily in insects rather than humans). However, there is enough of a precedent to provide a foundation for the imagination. Throw in the hypothesis that the agent was developed for military purposes and it would seem that we have a winner.
Thus it would seem that zombies (of a sort) are possible. Happy Halloween.
To me, before you can answer the question “Can the dead walk?” you have to define what you mean by “the dead” and, therefore, death. It also seems clear that defining death requires some consideration of the opposite state: life. Among other things, living things are commonly held to have three characteristics: the ability to grow, reproduce and to respond to stimuli (irritability) (paraphrasing from “Henderson’s Dictionary of Biology”).
Obviously, prior to becoming zombies, normal people exhibit these characteristics. What about zombies?
Consider the zombies in the Resident Evil movies. They are created when people become infected by the T-virus, die (presumably, although I’m not sure this is ever clearly stated) and then their dead tissues are “reanimated” by the virus.
RE zombies have some limited capacity to respond to stimuli — they have a hunger for flesh but do not require it (RE 3) — but they certainly do not grow or reproduce. (Actually, these zombies must have some limited capability for cellular repair and defense, otherwise they would rot and decay within a few days, instead of the several months that the process appears to take.)
RE zombies are, therefore, not alive — they do not possess all the required characteristics of living things — but they do walk. The answer to the question, therefore, is: Yes, the dead can walk.
(For the purposes of this discussion I am leaving aside the unresolved, and minor, problem of HOW the T-virus “reanimates” dead tissue, although I believe Umbrella Corp is working on this.)
Keith,
Quite right-sorting out when something is dead can be a rather difficult matter. After all, humans do “come back to life” after they stop breathing and moving and, of course, certain cells do keep on going for a while even when the main organism is supposed to be dead.
Zombies, as you note, do respond to stimuli (mostly the presence of living humans). In some sense, certain types of zombies could be taken as reproducing. After all, most standard movie and TV zombies can infect living humans and transform them into zombies, thus reproducing their kind. As you do note, they are not supposed to grow (well, other than the ones that turn into other sorts of undead monsters) as living things do.
For my own zombies, I “solve” the rotting problem by having the animating agent protect their host from decomposition (by fending off bacteria and preventing insect infestation). I’ve also been toying with the idea of animating bacteria that keeps the other bacteria from eating their host.
Mike: “After all, most standard movie and TV zombies can infect living humans and transform them into zombies, thus reproducing their kind.”
But this is not reproduction! This is merely a mechanism by which the infection spreads! After all, when a mosquito, for instance, spreads malaria from one human host to another, IT is not reproducing, the parasite is.
I don’t see the “rotting problem” as a fatal flaw in the possibility of zombies: you have a solution to this.
The real tricky problem for zombies is where they get their energy, if they actually do not need to feed.
It depends on how you see reproduction. True, mosquitoes do not reproduce via malaria. But, a zombie that bites a human would thus create another zombie, which could be seen as a form of reproduction-they can make more zombies.
The energy problem does seem to be a serious one for the “scientific zombies.” With supernatural zombies, they can just keep going magically. But the non-magical zombies would need to use energy to keep on going. Now, if the animator consumes the body of the zombie, then the zombie would eventually run down. The classic (Romero) zombies consume flesh, but do not actually digest it (they even try to eat when their stomachs are removed) so their source of energy is a mystery. Perhaps they are solar powered?
Sometimes I am reasonably convinced that about 97% of the world is in fact comprised of the walking dead.
It would be an interesting thought experiment to attempt to refute this.
Mike: “It depends how you see reproduction”. Zombie reproduction, e.g. by infection, turns existing bodies into zombies: it does not create NEW bodies. Creating NEW individuals is the key element, biologically (and I think philosophically), as only this type of reproduction can lead to an increase in the population. the zombie-infection process stops as soon as all the bodies have been infected. (I am a biologist.)
Leo: Your point is clear but it is important to remember that life does not require sentience. Over 99.99% of living things (whether reckoned by biomass, number of species or number of individuals) is non-sentient, and, generally, they seem to do fine. In fact, if we wiped ourselves out, we would be survived by non-sentient life.
Hmm. I am not sure what sentience *means*.
I meant, of course, 97% of the (human population of the) world…
Leo Smith,
One of my grad school professors said that he often thought of the people on campus as being machines set out to impede his progress across campus.
Keith,
Perhaps a zombie is a new individual (suppose that the original person is gone-the soul leaves the body, the functional states change enough for there to be a new person or whatever theory of PI you like) and “undead” reproduce by transforming the living into their own kind. To use an organic analogy, imagine an insect species that laid its egg in another insect. The egg hatches and consumes the host, but also replaces the host as it consumes it, so the result is a mimic of the original insect. For each “mimic” that is born, another insect must be consumed-like the zombies.