Physics for the Soul

As the United States shuts down its eastern seaboard for Cyclone Sandy, the Philippines will be shutting down as well, for completely different reasons. November 1 marks All Saints’ Day, when many establishments close up, since most people head to cemeteries to gamble and eat among the remains of the dead.

What comes with the holiday is the belief that when our bodies cease to function, even after we are laid into the soil or burned to ash, something survives. We are not just bodies, supernaturalist believers claim. There is a ghost in this machine and it breaks free from its mortal shackles upon death.

Some people claim to see these surviving entities, these spirits or souls, dwelling among the living. Ghostly apparitions are reported with disturbing regularity. Disturbing, in that even in the age of ubiquitous photography, no one has ever gathered any credible support for these ectoplasmic assertions. The reality of disembodied souls would necessarily overturn everything we know about physics. Any scientist would be itching to find evidence for the supernatural—evidence that never seems to turn up, despite the most adamant and most confident protestations of believers.

Human visual perception works because of light, and light works through electromagnetism. Electromagnetic/light particles called photons travel at the speed limit of the universe. When they hit objects, the energy of the photons is absorbed by particles in the object (such as electrons). These particles then release some energy back as another photon. The energy of the photon released determines the color and intensity of the light humans perceive.

If ghosts (under which I include saintly apparitions) can be seen, that means ghosts interact with photons! Electromagnetism is a physical phenomenon. This implies that at least some aspects of ghosts are physical, and therefore investigable by the methods of science. What kinds of photons are these spirits carrying? Are they different from everyday photons?

When people claim to hear ghosts, either through spooky screams or through elaborate homilies about the current geopolitical situation, they are actually claiming that physical objects are being moved by supernatural events. The perception of hearing occurs when the pressure of the air around us is locally fluctuated. When people talk, their vocal folds vibrate and push around air molecules. The air then vibrates the eardrums of animals within earshot. These vibrations correspond to what we hear as sound. The case is similar for those who report interacting with apparitions through touch (except that objects apart from air molecules are being moved, such as a uterus).

The Earth rotates on its own axis at around 1,674.4 km/h. It revolves around the Sun at 108,000 km/h. We don’t even feel these exorbitant speeds because we are moving with the Earth. We move with the Earth because we are on it and its forces are acting on us without variation. Should the Earth suddenly change in speed, however, we would definitely feel a calamitous disturbance. The Earth is tumbling around our galaxy, which is itself moving with respect to the rest of the universe. Should the Earth’s motion stop, we’d fly off into space—like a tetherball released from its rope. For the most part, we can happily ignore that we are hurtling across space because we are physical objects that obey the laws of physics. It is curious, therefore, when even immaterial ghosts follow physical laws.

When people claim to see ghosts, nobody ever reports them appearing one moment then zipping out into space the next, left behind by the Earth’s motion. Rather, people claim to see them stay in place long enough to scare the bejesus out of them, or tell them about some magic water that would heal people. Again, ghosts are eerily physical in all convenient aspects.

Imagine now that you have died. Ignore the paradox that you could not do such imagining because that would be imagining that your imagination could not imagine any longer. For the sake of argument, let us say that souls do exist and you are one right now, formerly in control of a body, currently disembodied.

Where are you? What do you see? Let us suppose that even though you are supernatural, you have some sort of particles that interact electromagnetically. Can you blink? It would be odd to do so, seeing as your soul would need to have eyelids.

At what direction are you looking? When you had a body, your eyeballs would sense a local cone of vision. Now that you’re a ghost, do you see all of existence at once? If so, where in the world are you? Certainly not floating just above your corpse.

When you had a body, you used your vision (and other senses) to determine where you were. You were limited by the local area that could be perceived by your physical sense organs. Now that you are without a body, the question of ‘where’ becomes meaningless. If ghosts exist, then they must be everywhere. They cannot otherwise be.

If these ghosts cannot exist as they have been claimed to be, then it must be that they are wholly in the mind of those who see them. They don’t have photons bouncing off of them, they don’t fly through space, because they’re not in the outside world! They do not exist objectively. These disembodied souls are figments, like how optical illusions, while very convincing, do not really show moving objects.

Our brains are easily fooled into seeing things that do not exist. People who claim to see ghosts often truly believe that they have experienced such a thing. I do not believe that they are all liars (though some must be). However, even though their brush with the supernatural must have felt very real, that does not mean that it was anything more than a psychological episode. The human brain is so adept at pattern recognition that it sees patterns everywhere—from clouds to dog anuses. It is no surprise, then, that ghosts follow the patterns we are so familiar with and that they are so much like normal natural objects, except for that little difficulty of being able to show them to others.

The supernatural world is suspicious to the scientifically literate because it is too convenient. It looks exactly like the natural world except when it’s favorable not to be. It looks like bad science fiction. Ghosts can hover, but not be left behind by a moving Earth. Ghosts can pass through solid walls, but can affect air molecules to produce sound. Ghosts can be perceived but not leave behind any independently-verifiable traces.

Surely some scientist must have left from the spirit world by now to show all his skeptical journal-publishing colleagues that the supernatural does exist. And yet, no scientist has ever come back from the grave to do so. Instead, we have saints who supposedly cure comatose patients, almost 400 years removed.

The vastness of space and time is available to the dead, if we are to believe the claims of the religious. Despite that, what is regularly professed to be done from beyond the grave is so vapid that miraculous claims are barely worth a 30 second spot on the evening news. The deep incongruence between the scale of the universe and the parochial concerns of people betrays the very human imaginations that spawn these stories.