I just returned from a week in a farmhouse in Texas near San Antonio, visiting relatives (and a grandchild), where we got to see lightning and rain and an armadillo and a scorpion and a newborn calf. I also caught up on some good reading as well as some bad.

One of the less-good reads was Goddess Murder: A Tale of Love, Witches, and Gnostics, by Aidan Kelly: a somewhat perfunctory reprise of the basic plot from Dan Brown’s The DaVinci Code, not particularly well-written, but there were some interesting concepts in the middle of it.

Many of you may have heard of “eidetic memory,” sometimes called “photographic memory.” It’s a kind of remembering in which you don’t merely recall the story about an experience — instead, you remember the experience itself in full detail, just as if you had taken a photograph. People with eidetic memory can replay the experience, and pick out details they hadn’t consciously noticed before.

One of the classic parlor tricks of eidetic memory is scanning rapidly through a book, merely glancing at each page, and then actually reading it later, from memory. You can ask someone with this kind of recall to name the fifth word from the end of the last full paragraph on page two hundred thirteen, and they can flip back through the pages in their mind and tell you the exact word. It’s as if they had the book in front of them.

“Eidetic imagination” carries the same sort of sensory photorealism, but it applies to the imagination rather than memory: that is, it doesn’t require any original sensory input to provide a full sensory experience.

A common term for this is “hallucination.”

To the best of my knowledge, I have outright hallucinated only once. It was in the winter of 1980-1981, around Christmas, when I was in graduate school and my wife was working in the dental school to pay the rent. That winter I contracted an adult case of chicken pox — at least, that’s what we believe it was, based on symptoms. My medical insurance at that time was through an HMO on Long Island, which — to put it very mildly — sucked down raw sewage and purred with pleasure at the flavor: the HMO doctors told my wife to NOT bring me in, since I was only going to infect other patients. They said to keep my fever down and wait it out. Or in other words, take aspirin, and call in two weeks. If I was still alive.

I had a recurring fever that went up to 105 degrees several times, perhaps even higher during some of the multi-hour spans when my wife couldn’t keep the aspirin flowing and the damp cloths cool because she was busy at work trying to hang onto the job that gave us the “benefits package” that might have paid for my burial in a mass grave if I didn’t survive.

It was during one of those fever-spikes that I hallucinated: I saw purple and green vines growing up the walls of the room. The fascinating part of that is that I knew I was hallucinating, not because I saw purple and green vines visibly climbing the walls of my bedroom — that part seemed perfectly reasonable in the hot, damp environment inside my skin — but because I knew that the room was too dark to see colors.

You see, the human eye has two different sets of light receptors in the retina, the receptors that see light intensity (rods) — but only see in shades of gray — and the receptors that distinguish colors (cones). The cones need a lot more light before they start working than the rods do. That’s why “twilight” fades into colorless shades of gray: the light becomes too dim for the cones, so the cones stop working and color disappears.

This bit of science trivia is what tipped me off that I was hallucinating.

That’s a cute story. But here’s where things start to get interesting.

All of us are hallucinating continually during every waking moment.

We don’t perceive reality. We receive sensory input through organs that collect various kinds of information, and we use this information to construct an elaborate model in our heads that we call reality, but is actually an imaginary model: a virtual reality that has been constructed by our brains. What we perceive is this virtual reality.

Children’s activity books are full of little tricks and traps and puzzles to mislead the senses into seeing, or hearing, or touching things that aren’t there, such as the elusive black dots in the figure to the right. Conversely, the senses can be tricked into not seeing, not hearing, and not feeling things that are there: the entire art of stage and close-up magic is based on this principle. The appearance of movement in television and film is based on an illusion produced by our brains. Storytelling allows us to experience and share events that have never occurred, and will never occur: for many of us, Frodo’s final ascent of Mount Doom is more real and present than most of third grade.

The “reality” that we each experience is not reality: it is a mental model that exists only in our imagination. What we call “reality” is in fact an exercise of eidetic imagination: a full-sensory hallucination.

Now, I’m not going to sit here and say that this hallucination is not useful. It’s extremely useful. Catching a baseball is fairly easy, based on the illusion that the ball is a solid object that obeys Newtonian physics, and is “out there” in the world exactly as we perceive it. Intercepting a cluster of Heisenberg probability waves propagating through the curved space-time surrounding the Earth is not nearly as easy — or worse, charting resonating strings in a ten-dimensional manifold that some physicists believe is the true nature of reality. Our simplistic model of reality lets us catch the ball, harvest a crop, shelter from cold rain, and get on with life.

Where we go wrong is in thinking that our eidetic hallucination is reality. That kind of thinking is simply hubris, one of the things that humans truly excel at.

Our vision of reality is a limited vision of reality, limited by our senses and by the way our brains are wired to interpret those senses and build our eidetic imagery.

I recently saw video footage which claimed to be made with a special camera that can see a short distance into the ultraviolet spectrum, which the human eye cannot register, though some bird and insect eyes do. The footage shows high-tension power lines, surrounded by a fireworks display of bright flashes, presumably in the ultraviolet spectrum. We scoff at suggestions by “oversensitive” people who say that high-tension power lines bother them, or that they might be disturbing or harmful to birds and insects. People say that “seeing is believing,” but many turn that around into “believing requires seeing.” For them, ultraviolet flashes around power lines are impossible, because they can’t be seen.

This was exactly the kind of resistance Galileo faced with his telescope. The telescope extends human eyesight to allow us to look at things further away than the unaided human eye can resolve. When turned on the planet Jupiter, it revealed things that were not already part of the mental model of reality that some church leaders held, and was roundly condemned.

There are vast tracts of unwritten natural history all around us of which we are utterly unaware, because we do not have the senses to perceive, nor the wit to infer.

If these vast tracts of unwritten natural history remained permanently invisible and impalpable, with no consequences for human life, we could argue that they have no practical reality, even if they do — in some abstract sense — exist. But, you see, they often do have effects that have a lot of direct impact on our lives.

Germs come to mind. Too small to be seen with any of our natural senses, yet they wipe out families, tribes, and empires. We don’t need to invoke high technology to make use of information about germs: simply washing our hands before eating can have a huge impact on our collective quality of life. Because we have extended our senses with the microscope, and have learned to observe cause-and-effect patterns in a systematic way, we have added germs to our model of reality, though they are invisible to us, and thus we understand the value of washing our hands.

But without the idea of germs and the invisible, impalpable reality they represent, our compulsive hand-washing before eating looks suspiciously like a superstition. After all, what are you washing off? Invisible evil spirits? Bad energy? Tiny demons?

This last is the closest to what we think about germs. Because we’ve extended our senses with the microscope, we can see the little buggers, and some of them actually look a lot like tiny demons. So imagine time-travelling back to the year 1 in Rome, and trying to explain germs to your average Roman scholar. Or time-travel into the year 4000, after modern civilization has largely turned to dust, and try to explain germs to whatever kind of learned man exists in that era:

As Professor Wizzletop has noted in his monograph on compulsive superstitious practices of the late 20th century, we have hand-washing before meals as one of the plainest examples. People of the 20th century believed in tiny demons that would accumulate on the hands and cause illness if ingested. A superstitious fetish developed, that progressed from washing the hands with plain water before every meal, to using various kinds of magical ointments crafted from a mythical substance they called “petroleum,” which they allegedly drew from the ground with magical tubes. Although we possess no evidence of either this mythic “petroleum” or its various decoctions, some writers from the late 21st century seem to believe that the “antimicrobial detergent,” used as part of the hand washing ritual was toxic. Perhaps this explains the rapid decline in population in the early 22nd century.

Trying to describe the nature and classification of germs to Professor Wizzletop would be a lot like a Medieval scholar trying to describe the hierarchies of demons in Hell to a modern microbiologist.

“But our model of reality works,” the skeptic would say. “That’s what science is all about. Superstition by definition doesn’t work.”

That’s much less true than most people think.

In the first place, our abstract models of reality aren’t nearly as sure-fire workable as people think. Drug trials, for instance, often require massive randomized double-blind studies to confirm the efficacy of a new drug, and most of them fall well into the thin fringes of “statistical significance.” You’ll often read that, of a sample of 100 people given the drug, and 100 people given placebos, 60 got better using the drug, and 50 got better without using the drug. Most researchers would be ecstatic over such a clear indication that the drug “works,” especially if a second trial showed 55 got better with the drug, and 49 better without. More typically, the second trial will show that 50 got better with the drug, and 52 better without. Our modern scientific pharmacopeia abounds with such marginal drugs.

In the second place, superstition is often based on an observed regularity in nature, combined with some convenient but non-essential explanation that fits the common abstract reality of a culture. For instance, “That water well is haunted by a malignant spirit, and if you drink from it, you will die.” We moderns might call the malignant spirit “lead oxide,” and would agree that if you drink very much of the water, you will die. If we can’t get to the source of the lead to exorcise it, our learned advice would be exactly the same as the superstitious advice of the primitive witch-doctor: don’t drink the water.

Human life is less centered on the mundane than upon the spiritual, however, even when times are hard. In fact, especially when times are hard: we are the least spiritual when our material needs are most sated, and the most spiritual in the face of hardship.

I find that peculiar: our standard rational model of self-interested survival behavior would tend to predict the other way around. I recognize it’s an anecdotal observation: I can’t tell you for certain that there are no atheists in foxholes. But it’s a common enough observation that when people are badly stressed by life-threatening events or illnesses, or by widespread social disorder, they pretty reliably turn to the spirit world. Why?

I’ll offer my own personal speculation. I think we have spiritual senses, and they sense a spiritual reality.

We downplay these senses in our culture, to the point of (officially) laughing off the spirit world, and discounting it as superstition. But I think our spiritual senses pick up aspects of reality that our more culturally accepted senses cannot, aspects as invisible and intangible to us as germs or ultraviolet light, aspects which are equally invisible and intangible to our instruments made of wire and glass and plastic.

When we’re out of practical solutions, these spiritual senses may offer us the best options we’ve got.

Like any senses, there are those who are gifted with great acuity, and those who are not. Young people use the “mosquito ring” on their cell phones precisely because their old-guy teacher, who goes ballistic when a cell phone rings in class, can’t hear the mosquito ring. The faint notes of Andalusian soil that a master sommelier can taste in a glass of Spanish grenache are simply not accessible to most people. So it isn’t surprising that not everyone sees auras, or ghosts, or angels.

Like any senses, we also have to learn to interpret them within a consensual social framework. Think how often you teach a child to associate a particular color sensation with the word “blue” or “red.” Think of how often an infant hears certain phonemes, and not others, in the language of his society, and then goes through life either able or unable to roll an “R”, or produce the “!” pop of the !Kung language.

What would happen if children were raised by aura-aware parents, who had a long cultural tradition of interpreting aura appearance? “I spy with my little eye … a man with a purple aura!”

These are the kinds of practice-games we play with our children and their developing senses to bring them into our culture and language, so that they see what we see, hear what we hear.  We teach them to distinguish primary colors because primary colors are important to our social structure, but we don’t make a big deal about azure versus cerulean. Without these games, without this kind of training in a communal setting, there is no consensus on the senses. What is the difference between music and noise? What is the difference between beauty and ugliness? What is the difference between an “arousing” touch and an “aggressive” touch? Which smells are interesting, which are boring, which are attractive, which are disgusting? What should we pay attention to, what should we block out as a distraction?

Most people have at least once stepped into a particular place and sensed some sort of frisson. A chill, a vibration, a flow, an ineffable sound. We are taught to ignore such things as a “bit of undigested beef.” But in the past, when a lot of people felt the same sort of thing in the same place, they built a shrine, or posted warning signs: holy ground, or cursed ground.

I would speculate that our spiritual senses tell us about aspects of our reality that are entirely natural, but are unknown to and actively suppressed by our current culture. I would also speculate that these aspects of our reality, though as invisible as germs, have a lot to do with our survival, good health, and happiness.

When fully developed, I see no reason our spiritual senses could not feed into our eidetic imagination the same way our other senses do, and become just as “real” to us as a sunset, or a sip of cool water.

As it turns out, some people claim that this is exactly how they experience the spirit world: as a full-scale eidetic hallucination, just as real to them as the sensory eidetic hallucination that all the rest of us experience all day, every day, and call “reality.”

I’m not one of those people. I don’t know if that’s fortunate or unfortunate. But then, I’ve never had good eyesight, and as I get older, my hearing closes in, bit by bit. I don’t expect to have the best spiritual senses in the world, either.

I’m also no stranger to the fact that people can be insane, and a lot of people lie. People who say they see dead people may just be nuts. Everything the hardcore skeptics say about the spiritual world may be completely accurate.

On the other hand, I take a very pragmatic attitude toward this, which I will illustrate with a true story.

The first house I owned had a haunt. There was no poltergeist activity, no spectral apparitions, no oozing ectoplasm from the walls. But there was a “presence” in the basement, and it was unpleasant. Every time I went to the basement — it was a small house, and that’s where my piano ended up — I had to fight my instinct to run back up the stairs as I approached the bottom, and I could not stay down there for long. Obedience-trained dogs would stay at the top of the stairs and whine, rather than go down as commanded. My wife didn’t like doing laundry down there.

At that time, we attended the Episcopal Church, and about three months after we moved into the new house, we decided to have a multi-purpose party: a first-birthday party for my son, a summer barbecue, a house warming party, and a house blessing. Episcopalians have a Book of Common Prayer blessing for everything (except garden zucchini, which I think may actually be in there, but our priest explicitly refused to bless zucchini under any circumstances).

So there I was, a newly-minted physicist just out of graduate school, having my newly-purchased house blessed in a quaint traditional custom in (truth told) my wife’s religious tradition, and I was dying to ask the priest, whom I did not yet know well, to drive an evil spirit out of the basement. The embarrassment was … exquisitely uncomfortable.

I finally just blurted it out, about halfway through the blessing of the basement. He didn’t even blink. “Oh,” he said, “yes, we can certainly take care of that.” He flipped over to the general exorcism in the Book of Common Prayer. An instant after he finished, the basement was clear. It was suddenly just a basement.

Now, any number of things could have happened. The professional skeptic will chalk it up to pure psychological drama going on in my head (and through me and my subliminal physical cues, my wife and the priest and maybe even the dogs). I don’t disagree at all — it might very well have been exactly that. The religious person would say that an unclean spirit was in fact driven out of the house by the Episcopal Rite of General Exorcism. I don’t disagree with that, either.

But the pragmatic point is that this simple religious rite recovered the use of 1500 square feet of my property. Before that, I could not go downstairs to play the piano. After that, I could. The third movement of my piano concerto was composed in that very room.

The professional skeptic’s theory would have recommended twenty years of intensive psychotherapy for me, maybe drugs, to the tune of $100k and ruined health from long term prescription drug use. It would not have given me back my basement for years, if (indeed) at all. Instead, I got away with a practical working solution that same day for the cost of a plate of ribs and a couple of beers, and made a lifelong friend into the bargain.

I see no contest here. The skeptic’s “solution” is a load of crap. The superstitious solution was the practical one.

I don’t really know what the “spirit world” is, and I doubt that I ever will. It may be a parallel dimension with its own space and time. It may be some kind of mystical self-organizing energy in this universe. It may be patterns that exist in the way people interact with their physical environment, including other people. It may be something else, entirely.

Whatever it is, I think we do have senses that perceive it, and as my story indicates, certain superstitious actions — whether it is washing our hands before eating, or sprinkling holy water around a basement, leaving out a plate of milk for the wee folk, or practicing gratitude on a daily basis — interact with the spirit world, whatever it is, and bring about beneficial effects.

So if some people claim to have an eidetic imagination that can accurately represent their spiritual senses — if they can see and talk to the dead, speak with angels, talk to God or the gods — I’m not going to scoff.

I would consider that an act of hubris. To say nothing of being just plain rude.