A zombie is a reanimated corpse devoid of consciousness. In contemporary versions these are generally undead corpses, which were traditionally called "ghouls". Stories of zombies originated in the Afro-Caribbean spiritual belief system of Vodou.

Other more macabre versions of zombies have become a staple of modern horror fiction, where they are brought back from the dead by supernatural or scientific means, and eat the flesh or brains of the living. They have very limited intelligence, and may not be under anyone's direct control. This type of zombie, often referred to as a Romero zombies after the filmmaker who defined the concept, is archetypal in modern media and culture.

Voodoo

A Haitian zombie at twilight in a field of sugar cane.

According to the tenets of Voodoo, a dead person can be revived by a bokor or Voodoo sorcerer. Zombies remain under the control of the bokor since they have no will of their own. "Zombi" is also another name of the Voodoo snake god Damballah Wedo, of Niger-Congo origin; it is akin to the Kongo word nzambi, which means "god". There also exists within the voudon tradition the zombi astral which is a human soul that is captured by a bokor and used to enhance the bokor's power.

In 1937, while researching folklore in Haiti, Zora Neale Hurston encountered the case of Felicia Felix-Mentor, who had died and been buried in 1907 at the age of 29. Villagers believed they saw Felicia wandering the streets in a daze thirty years after her death, as well as claiming the same with several other people. Hurston pursued rumors that the affected persons were given powerful drugs, but she was unable to locate individuals willing to offer much information. She wrote:

"What is more, if science ever gets to the bottom of Voodoo in Haiti and Africa, it will be found that some important medical secrets, still unknown to medical science, give it its power, rather than gestures of ceremony." ^[1]

Several decades later, Wade Davis, a Canadian ethnobotanist, presented a pharmacological case for zombies in two books, The Serpent and the Rainbow (1985) and Passage of Darkness: The Ethnobiology of the Haitian Zombie (1988). Davis traveled to Haiti in 1982 and, as a result of his investigations, claimed that a living person can be turned into a zombie by two special powders being entered into the blood stream (usually via a wound). The first, coup de poudre (French: 'powder strike'), induced a 'death-like' state because of tetrodotoxin (TTX), its key ingredient. Tetrodotoxin is the same lethal toxin found in the Japanese delicacy fugu, or pufferfish. At near-lethal doses (LD₅₀= 5-8µg/kg)^[2], it can leave a person in a state of near-death for several days, while the person continues to be conscious. The second powder, composed of dissociatives like datura, put the person in a zombie-like state where they seem to have no will of their own. Davis also popularized the story of Clairvius Narcisse, who was claimed to have succumbed to this practice. There remains considerable skepticism about Davis's claims,^[3] although there is wide belief among the Haitian people of the existence of the "zombie drug". The Voodoon religion being somewhat secretive in its practices and codes, it can be very difficult for a foreign scientist to validate or invalidate such claims.

Others have discussed the contribution of the victim's own belief system, possibly leading to compliance with the attacker's will, causing psychogenic ("quasi-hysterical") amnesia, catatonia, or other psychological disorders, which are later misinterpreted as a return from the dead. Scottish psychiatrist R. D. Laing further highlighted the link between social and cultural expectations and compulsion, in the context of schizophrenia and other mental illness, suggesting that schizogenesis may account for some of the psychological aspects of zombification.

 Folklore

In the Middle Ages, it was commonly believed that the souls of the dead could return to earth and haunt the living. The belief in revenants (someone who has returned from the dead) are well documented by contemporary European writers of the time. According to the Encyclopedia of Things that Never Were^[4], particularly in France during the Middle Ages, the revenant rises from the dead usually to avenge some crime committed against the entity, most likely a murder. The revenant usually took on the form of an emaciated corpse or skeletal human figure, and wandered around graveyards at night. The "draugr" of medieval Norse mythology were also believed to be the corpses of warriors returned from the dead to attack the living. The zombie appears in several other cultures worldwide, including China, Japan, the Pacific, India, and the Native Americans.

The Epic of Gilgamesh of ancient Sumer includes a mention of zombies. Ishtar, in the fury of vengeance says:

Father give me the Bull of Heaven,

So he can kill Gilgamesh in his dwelling.

If you do not give me the Bull of Heaven,

I will knock down the Gates of the Netherworld,

I will smash the doorposts, and leave the doors flat down,

and will let the dead go up to eat the living!

And the dead will outnumber the living!

translated by Maureen Gallery Kovacs

 Popular culture

Modern zombies, as portrayed in books, films, and haunted attractions, are quite different from both Voodoo zombies and those of folklore. Modern zombies are typically depicted in popular culture as mindless, unfeeling monsters with a hunger for human flesh, a prototype established in the seminal 1968 film Night of the Living Dead. Zombies have been the subject of many horror films since, and occur as antagonists in many video games. There are still significant differences among the depictions of zombies by various media; for one comparison see the contrasts between zombies by Night of the Living Dead authors George A. Romero and John A. Russo as they evolved in the two separate film series that followed.

 Philosophy

In philosophy of mind, zombies are hypothetical persons who lack full consciousness but have the biology or behavior of a normal human being; thought experiments involving them are often used as arguments against the identity of the mind and the brain. The term was coined by philosopher of mind David Chalmers. They are referred to as philosophical zombies or "p-zombies". ^[5]