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Cinema Fiction vs. Physics Reality: Ghosts, Vampires, and Zombies


Costas J. Efthimiou and Sohang Gandhi

Skeptical Inquirer Volume 31.4, July / August 2007

For many people, ghosts, vampires, zombies, and the like are no more than Hollywood fantasy. However, these movies have increasingly come to reflect popularly held pseudoscientific beliefs. For instance, the 2005 movie White Noise is based on the new trend among paranormalists—Electronic Voice Phenomena (EVP). The occult underground in both America and Europe is witnessing a trendy rise in vampirism, and belief in voodoo zombiefication is widespread in many parts of South America and Africa. Furthermore, paranormal depictions in the media, especially television and Hollywood, have a definite influence on the way people think about paranormal claims(see, for example, Sparks 1998 and Sparks 2006).

In this article, we point out inconsistencies associated with the ghost, vampire, and zombie mythologies as portrayed in popular films and folklore and give practical explanations to some of their features. Of course, the paranormalist or occultist could claim that the Hollywood portrayal is a rather unsophisticated and inaccurate representation of their beliefs and thus the discussion we present is moot. However, if they are to change their definition each time we raise an issue, then all that they are really arguing is that there exists something out there that may be given the name “ghost,” for instance. Surely, no skeptic could argue with this.

Ghosts Sudden Cold

Figure 2. These diagrams show the motion of convection currents in a fluid.

Figure 2. These diagrams show the motion of convection currents in a fluid.

It has become a Hollywood cliché that the entrance of a ghostly presence is foreshadowed by a sudden and overwhelming chill (see, for example, The Sixth Sense). In fact, sharp temperature drops are very commonly reported in association with supposed real-life encounters with ghosts or poltergeists. This feature of supposed ghost sightings lends itself naturally to physical explanation.

The famous Haunted Gallery at Hampton Court Palace near London is reputedly stalked by the spirit of Catherine Howard, who was executed on February 13, 1542, by order of Henry VIII. Visitors to the room have described hearing screams and seeing apparitions in the gallery. A team of ghost-busting psychologists, led by Richard Wiseman1 of Hertfordshire University, installed thermal cameras and air-movement detectors in the gallery. About 400 palace visitors were then quizzed on whether they could feel a “presence” in the gallery. More than half reported sudden drops in temperature, and some said they sensed a ghostly presence. Several people claimed to have seen Elizabethan figures.

Before moving on to an explanation, we will need to outline the concept of heat. When a “warm” object is placed next to a “cool” object (see Figure 1) energy will begin to flow from the warmer body (causing it to cool) to the cooler body (causing it to warm). This energy, which is being transferred between the two objects due to their difference in temperature, is called heat. Note that an object is never said to “possess” any amount of heat; heat is only defined through transfer. For instance, no matter how hot a stove, it never possesses any degree of heat. When someone suddenly touches the stove, however, there is heat—it is the energy flowing from the stove to that person’s hand.

As heat continues to be transferred from the warmer body to the cooler one in figure 1, and the warmer body’s temperature continues to drop while the cooler body’s temperature climbs, there comes a point when the two bodies are at the same temperature. At this point, heat ceases to flow between the two objects, since neither is the hotter one and heat has no definite direction in which to be transferred. This condition is called thermal equilibrium.

In our stove example, heat was transferred via conduction—the exchange of heat through direct contact. There are other ways that heat can be transferred. These involve the exchange of heat by two objects separated by some distance. If these two objects are emersed in a fluid (Earth’s atmosphere, for example), then the warmer body may provide heat to the fluid in its immediate vicinity. This warmer fluid will then tend to rise, thus coming in contact with a cooler body above. There may also be a lateral current in the fluid, thus allowing the heated fluid to affect a cooler body to the side. This type of heat transfer, by an intermediary fluid, is called convection.

Figure 3 left Figure 3 right

Figure 3. These two stills are taken from the movie Ghost. In the left still, the ghost goes through a door. In the right still, the ghost, who follows a burglar in his girlfriend’s home, loses his balance as he ascends the staircase and falls on—not through—the stairs.

In figure 2a, we give a simplified example of what are known as convection currents. Suppose that the right wall is kept warm and the left wall is kept cool. Air in contact with the right wall will tend to gain heat and then rise, while air in contact with the left wall will tend to lose heat and then sink. The circular flow that forms is called a convection current. Air cycles around in a loop, picking up some heat at the right wall, dropping it off at the left wall, and then coming back around again. Actually, the air-current pattern will be somewhat more complicated than what we just described. There will be all kinds of smaller cycles and eddies embedded in complex patterns, as in figure 2b. The overall flow, however, will be as in figure 2a.

The third mode of heat transfer allows for exchange between two separated objects even if they are in a total vacuum. How can two objects exchange heat if there is no matter in between them? The answer is radiation. The thermal energy of a body is expressed in the “jiggling” of its various constituent particles. As electrically charged particles within a body jiggle about, they produce electromagnetic waves. When these waves hit another body, they cause the particles in that body to jiggle more than they were before, and the body heats up. Since hotter bodies produce more of this radiation, there will be more radiation from the hotter body falling upon the cooler body than from the cooler body falling upon the hotter body. Thus, overall, the hotter body will be losing heat while the cooler body will be gaining heat. We will not be too concerned with this particular mechanism for heat exchange in this article.

Returning to the Haunted Gallery at Hampton Court Palace, Richard Wiseman’s team reported that the experiences could be simply explained by the gallery’s numerous concealed doors. These elderly exits are drafty, and the combination of air currents they let in cause sudden changes in the room’s temperature. In two particular spots, the temperature of the gallery plummeted by up to 2°C (3.6°F). “You do, literally, walk into a column of cold air sometimes,” said Wiseman. “It’s possible that people are misattributing normal phenomena . . . . If you suddenly feel cold, and you’re in a haunted place, that might bring on a sense of fear and a more scary experience.” Thus, the rumor that “cold spots” are associated with ghosts seems to be a myth created by the construction of old buildings and vivid imaginations.

But how could a few degrees drop in temperature explain the dramatic chills described in so many ghostly accounts? First off, what we sense as cold is not correlated to temperature so much as to the rate at which heat is being transferred from our bodies to the environment. For instance, even in a temperate pool, one feels a very sharp chill when one first enters. A moderate draft containing condensed moisture could cause a very sharp sensation of cold. Second, we are all aware of the “tall-tale” effect. Memories tend to become distorted and exaggerated. It is exactly this reason why scientists tend not to rely on unchecked eyewitness accounts.

The Inconsistency of the Notion of Immaterialness

Figure 4. Newton’s third law, known as the action-reaction law, is demonstrated here.

Figure 4. Newton’s third law, known as the action-reaction law, is demonstrated here.

Popular myth holds that ghosts are immaterial. For instance, in the movie Ghost, the recently deceased main character tries desperately to save his former lover from a violent intruder. His attempts to intervene grant him no avail, as, at each lunge, he passes right through the perpetrator. It is interesting, however, that he was able to walk up the stairs at the same time. In fact, this is a common feature of the ghost myth. Ghosts are held to be able to walk about as they please, but they pass through walls and any attempt to pick up an object or affect their environment proves fruitless unless they are poltergeists, of course!

Walking requires an interaction with the floor, and such interactions are governed by Newton’s Laws of Motion. Newton’s first law is the law of inertia. It states that a body at rest will remain at rest until acted upon by an external force.

Therefore, a person cannot start walking unless a force, applied by some body other than herself, is acting upon her. But where is the force coming from? The only object in contact with the person while walking is the floor. So, the force moving a person while walking is coming from the floor. But how does the floor know to exert a force when the person wants to start walking and stop exerting it when the person wants to stand? Actually, there is no magic here. The person actually “tells” the floor using Newton’s third law.

Newton’s third law says that if one object exerts a force on another object, then the second object exerts a force that is equal but oppositely directed, on the first object—hence “for each action there is an equal but opposite reaction.” Thus, when the skate-boarder in figure 4 pushes on the wall, the wall pushes right back on her, causing her to accelerate off to the left.

Figure 5. Multiple forces act on the feet of a person while walking.

Figure 5. Multiple forces act on the feet of a person while walking.

The mechanics of walking are shown in Figure 5: the person wanting to walk must remain at rest unless a force acts on her. She gets the floor to apply a force on her by applying an opposite force on the floor with her foot. She keeps repeating this action, alternating feet. The point is that, for the ghost to walk, it must be applying force to the floor. The floor is part of the physical universe, so, in order to walk, the ghost must have an affect on the physical universe. If this is so, then we can detect the ghost via physical observation. The depiction of ghosts walking contradicts the idea that ghosts are immaterial.

So which is it? Are ghosts material or immaterial? Maybe they are only material when it comes to walking. Well, then we must assume that they can’t control this selective immaterialness, otherwise Patrick Swayze would have saved his girlfriend in Ghost. In this case, we could place stress sensors on the floor to detect a ghost’s presence. Maybe they walk by some other supernatural means. Well, why can’t they use this power to manipulate objects when they want to? Even more, it seems strange to have a supernatural power that only allows you to get around by mimicking human ambulation. This is a very slow and awkward way of moving about in the scheme of things. In any case, you’d have to go to some lengths to make this whole thing consistent.

Incidentally, the reader may have noticed that we skipped a law in our discussion. We discussed the first and third of Newton’s laws. Newton’s second law of motion states that the acceleration of an object—the rate at which it speeds up—is proportional to the net force applied, the constant of proportionality being the mass. We didn’t need the precise statement of this law but, silently, we did use it. The second law implies that the acceleration of an object will be nonzero (and thus the object will be able to change its state of motion) only if a net force is acting on it. This was exactly our statement: “Therefore, a person cannot start walking unless a force, applied by some body other than herself, is acting upon her.”


Anyone who has seen John Carpenter’s Vampires, Dracula, Blade, or any other vampire film is already quite familiar with the vampire legend. The vampire needs to feed on human blood. After one has stuck his fangs into your neck and sucked you dry, you turn into a vampire yourself and carry on the blood-sucking legacy. The fact of the matter is, if vampires truly feed with even a tiny fraction of the frequency that they are depicted as doing in the movies and folklore, then humanity would have been wiped out quite quickly after the first vampire appeared.

Let us assume that a vampire need feed only once a month. This is certainly a highly conservative assumption, given any Hollywood vampire film. Now, two things happen when a vampire feeds. The human population decreases by one and the vampire population increases by one. Let us suppose that the first vampire appeared in 1600 c.e. It doesn’t really matter what date we choose for the first vampire to appear; it has little bearing on our argument. We list a government Web site in the references (U.S. Census) that provides an estimate of the world population for any given date. For January 1, 1600, we will accept that the global population was 536,870,911.2 In our argument, we had at the same time one vampire.

We will ignore the human mortality and birth rate for the time being and only concentrate on the effects of vampire feeding. On February 1, 1600, one human will have died and a new vampire will have been born. This gives two vampires and 536,870,911—1 humans. The next month, there are two vampires feeding, thus two humans die and two new vampires are born. This gives four vampires and 536,870,911—3 humans. Now on April 1, 1600, there are four vampires feeding and thus we have four human deaths and four new vampires being born. This gives us eight vampires and 536,870,911—7 humans.

By now, the reader has probably caught on to the progression. Each month, the number of vampires doubles, so that, after n months have passed, there are

doubling rate of vampires

vampires. This sort of progression is known in mathematics as a geometric progression—more specifically, it is a geometric progression with ratio two, since we multiply by two at each step. A geometric progression increases at a tremendous rate, a fact that will become clear shortly. Now, all but one of these vampires were once human, so that the human population is its original population minus the number of vampires excluding the original one. So after n months have passed, there are:

536,870,911 - 2n + 1

humans. The vampire population increases geometrically and the human population decreases geometrically.

Table 1. Vampire and human populations at the beginning of each month during a 29-month period

Table 1. Vampire and human populations at the beginning of each month during a 29-month period

Table 1 lists the vampire and human population at the beginning of each month over a twenty-nine-month period. Note that by the thirtieth month the table lists a human population of zero. We conclude that if the first vampire appeared on January 1, 1600, humanity would have been wiped out by June of 1602, two and a half years later.

All this may seem artificial, since we ignored other effects on the human population. Mortality due to factors other then vampires would only make the decline in humans more rapid and therefore strengthen our conclusion. The only thing that can weaken our conclusion is the human birthrate. Note that our vampires have gone from one to 536,870,912 in two and a half years. To keep up, the human population would have had to increase by the same amount. The Web site (U.S. Census) mentioned earlier also provides estimated birth rates for any given time. If you go to it, you will notice that the human birthrate never approaches anything near such a tremendous value. In fact, in the long run, for humans to survive in the given scenario, our population would have to at least double each month! This is clearly far beyond the human capacity for reproduction. If we factor in the human birthrate into our discussion, we find that, after a few months, the human birthrate is very small compared to the number of deaths due to vampires. This means that ignoring this factor has a negligibly small impact on our conclusion. In our example, the death of humanity would be prolonged by only one month.

We conclude that vampires cannot exist, since their existence would contradict the existence of human beings. Incidently, the logical proof that we just presented is of a type known as reductio ad absurdum, that is, “reduction to the absurd.” Another philosophical principle related to our argument is the truism given the elaborate title, the anthropic principle. This states that if something is necessary for human existence then it must be true since we do exist. In the present case, the nonexistence of vampires is necessary for human existence. Apparently, whoever devised the vampire legend had failed his college algebra and philosophy courses.


Pic 1. Wilfred Doricent, the zombie, is shown in Haiti with his parents.

Pic 1. Wilfred Doricent, the zombie, is shown in Haiti with his parents.

The zombie legends portrayed in movies such as Dawn of the Dead or 28 Days Later follow a similar pattern to the vampire legends. Once you are bitten by zombies, while you may manage to escape immediate death, you will eventually die and turn into a zombie, yourself. Thus, this particular type of zombie legend suffers the same flaw that we previously pointed out for the vampire legend. We still have some more work to do, however. There exists a second sort of zombie legend that pops its head up throughout the western hemisphere—the legend of “voodoo zombiefication.” This myth is somewhat different from the one just described, in that zombies do not multiply by feeding on humans but come about by a voodoo hex being placed by a sorcerer on one of his enemies. The myth presents an additional problem for us: one can witness for himself very convincing examples of zombiefication by traveling to Haiti or any number of other regions in the world where voodoo is practiced.

We describe the particular case of Wilfred Doricent,3 an adolescent schoolboy from a small village in Haiti. One day, Wilfred became terribly ill. He experienced dramatic convulsions, his body had swelled tremendously, and his eyes had turned yellow. Eight days later, Wilfred appeared to have died. This was confirmed by not only the family and family friends present but also by the local medical doctor who could detect no vital signs. Wilfred’s body appeared to show bloating due to rigor mortis and gave off the foul stench of death and rot. He was buried soon thereafter.

Pic 2. Puffer fish such as this one are the source of a highly potent neurotoxin.

Pic 2. Puffer fish such as this one are the source of a highly potent neurotoxin.

Some time afterward, the weekly village cockfight was interrupted as an incognizant figure appeared. The villagers were shocked as they gazed upon the exact likeness of Wilfred. The person was indeed Wilfred, as his family verified by noting scars from old injuries and other such details. Wilfred, however, had lost his memory and was unable to speak or comprehend anything that was said to him. His family had to keep him in shackles so that he wouldn’t harm himself in his incoherent state. It appeared that Wilfred’s body had risen from death, leaving his soul in the possession of some voodoo sorcerer. Word of Wilfred’s “zombiefication” spread quickly throughout the village. It was believed that Wilfred’s uncle, a highly feared voodoo sorcerer who had been engaged in a dispute over land with Wilfred’s family, was the culprit. Wilfred’s uncle was later charged with zombiefication, a crime in Haiti equivalent to murder.

Is this truly a case of supernatural magic? To answer this question, we turn our attention to a highly toxic substance called tetrodotoxin (TTX). In an article in New Scientist (2001), Bryan Furlow gives an overview of TTX’s effects blended with a headlining news story:

Pic 3. Frère Dodo, a former voodoo priest, confirms that the recipe used to make the drug for zombiefication includes a powder derived from the puffer fish.

Pic 3. Frère Dodo, a former voodoo priest, confirms that the recipe used to make the drug for zombiefication includes a powder derived from the puffer fish.

At first the U.S. federal officers thought they had stumbled upon a shipment of heroin. The suspicious package they intercepted last year [2000], en route from Japan to a private address in the US contained several vials packed with a white crystalline powder. But on-the-spot tests revealed that it was no narcotic. It took a while for forensic scientists at the Lawrence Livermore National Laboratory in California to identify a sample, and what they found was alarming. The powder turned out to be tetrodotoxin (TTX): one of the deadliest poisons on Earth.

Gram for gram, TTX is 10,000 times more lethal than cyanide. . . . This neurotoxin has a terrifying modus operandi—25 minutes after exposure it begins to paralyze its victims, leaving the brain fully aware of what’s happening. Death usually results, within hours, from suffocation or heart failure. There is no antidote. But if lucky patients can hang on for 24 hours, they usually recover without further complications. . . .

The Livermore team estimated that to extract the 90 milligrams of TTX discovered by the Feds, you’d need between 45 and 90 kilograms of puffer-fish livers and ovaries—the animal’s most deadly tissues. No one knows what use its intended recipient had in mind. . . .

Pic 4. A doctor points to lesions in the ventricular system of the right frontal cone in a brain scan of Wilfred Doricent.

Pic 4. A doctor points to lesions in the ventricular system of the right frontal cone in a brain scan of Wilfred Doricent.

TTX is found in various sea creatures and, in particular, in the puffer fish. Puffer fish are a delicacy in Japan known as fugu that only trained and licensed individuals prepare by carefully removing the viscera. Of course, despite the care taken in preparation, about 200 cases of puffer-fish poisoning are reported per year with a mortality rate of 50 percent. The symptoms of the poisoning are as follows (U.S. FDA):

The first symptom of intoxication is a slight numbness of the lips and tongue, appearing between twenty minutes to three hours after eating poisonous puffer fish. The next symptom is increasing paraesthesia in the face and extremities, which may be followed by sensations of lightness or floating. Headache, epigastric pain, nausea, diarrhea, and/or vomiting may occur. Occasionally, some reeling or difficulty in walking may occur. The second stage of the intoxication is increasing paralysis. Many victims are unable to move; even sitting may be difficult. There is increasing respiratory distress. Speech is affected, and the victim usually exhibits dyspnea, cyanosis, and hypotension. Paralysis increases and convulsions, mental impairment, and cardiac arrhythmia may occur. The victim, although completely paralyzed, may be conscious and in some cases completely lucid until shortly before death. Death usually occurs within four to six hours, with a known range of about twenty minutes to eight hours.

Sometimes, however, a victim pronounced dead is lucky enough to wake up just before his funeral and report to his bewildered family that he was fully conscious and aware of his surroundings throughout the entire ordeal. Therefore, TTX has the unusual characteristic that, if a nonlethal dose is given, the brain will remain completely unaffected. If just the right dose is given, the toxin will mimic death in the victim, whose vitals will slow to an immeasurable state, and whose body will show signs of rigor mortis and even produce the odor of rot. Getting such a precise dose would be rare for a case of fugu poisoning, but can easily be caused deliberately by a voodoo sorcerer, say, who could slip the dose into someone’s food or drink.

The secrets of zombiefication are closely guarded by voodoo sorcerers. However, Frère Dodo, a once highly feared voodoo sorcerer, who is now an evangelical preacher and firm denouncer of the voodoo faith, has revealed the process. It turns out that zombiefication is accomplished by slipping the victim a potion whose main ingredient is powder derived from the liver of a species of puffer fish native to Haitian waters.

This provides an explanation for how Wilfred could have been made to seem dead, even under the examination of a doctor. However, we have already said that the TTX paralysis was unlikely to have affected his brain. How does one account for Wilfred’s comatose mental state? The answer is oxygen deprivation. Wilfred was buried in a coffin in which relatively little air could have been trapped. Wilfred’s story probably goes something like this: slowly, the air in Wilfred’s coffin began to run out so that, by the time he snapped out of his TTX-induced paralysis, he had already suffered some degree of brain damage. At that point, his survival instincts kicked in, and he managed to dig himself out of his grave—graves tend to be shallow in Haiti. He probably wandered around for some time before ending up back at the village. This topic was the subject of a horror film, The Serpent and the Rainbow.

Neuropsychiatrist Dr. Roger Mallory, of the Haitian Medical Society, conducted an MRI of zombiefied Wilfred’s brain. He and his colleagues found lesions of the type normally associated with oxygen starvation. It would seem that zombiefication is nothing more then a skillful act of poisoning. The bodily functions of the poisoned person suspend so that he appears dead. After he is buried alive, lack of oxygen damages the brain. If the person is unburied before he really dies from suffocation, he will appear as a soulless creature (“zombie”), as he has lost what makes him human: the thinking processes of the brain.


We have examined the science behind three of the most popular pseudoscientific beliefs encountered in Hollywood movies. We have shown two of them—the idea of ghosts and vampires—to be inconsistent and contradictory to simple facts. For the third—the idea of zombies—we have made no attempt to deny that it relies on real cases. However, we have reviewed evidence showing that the concept is a misrepresentation of simple criminal acts.

Popular belief in these myths is an indication of a lack of critical-thinking skills in our society. With simple arguments, one can easily discredit the validity of such claims. We thus finish with the following quote by Carl Sagan (Sagan 1979):

Both Barnum and H.L. Mencken are said to have made the depressing observation that no one ever lost money by underestimating the intelligence of the American public. The remark has worldwide application. But the lack is not intelligence, which is in plentiful supply; rather, the scarce commodity is systematic training in critical thinking.


  1. Details on his research may be found on Wiseman’s Web site at
  2. It may seem odd to the reader that we have specified the population with so much precision—we have a number in the one hundred millions and have specified it all the way down to the “one’s place” (. . . 911). We chose the particular value for convenience. The actual estimated population in the seventeenth century is 562±17 millions. Beyond mathematical simplification, our choice has little impact on the argument to follow. If we were to report any number in the range of possible values for the population in the year 1600, the end result of our calculations would be essentially the same.
  3. We claim no major originality in the presentation of what follows—except in collecting the material from the sources and arranging it as seen. Doricent’s case is nicely described in a documentary (Clark 2002). The relation between zombies and TTX was first noticed by the Harvard ethno-botanist Wade Davis in 1982.


Costas J. Efthimiou and Sohang Gandhi

Costas J. Efthimiou is a theoretical physicist at the University of Central Florida (UCF). He is the advisor to the local Campus Freethought Alliance (CFA) chapter, which he helped to establish at UCF. Address: Department of Physics, UCF, 4000 Central Florida Blvd., Orlando, FL 32816.

Sohang Gandhi received his BS in physics with honors. Among his many awards, he has been a Goldwater scholar, an NSF fellow and was selected for the 2006 all-USA third team. He has served as the president of the CFA chapter at UCF. In fall 2006, he began his graduate studies in physics at Cornell University.