Can the Dead Walk?
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.