Two different lines of discussion just came together for me in an interesting, albeit entirely speculative, way.

First, I got an email from a reader whose screen name is Eteponge. He discussed the fact that many out-of-body experiences and near-death experiences contain a mixture of valid and invalid perceptions. He gave the example of someone in an out-of-body experience who perceived a barbecue set in the neighbor's yard, when in fact there was no such barbecue, and the example of someone who hovered over his own body and perceived himself wearing long johns, when in fact he was not wearing them.

Second, I had a conversation with the medium Marcel Cairo (http://www.afterlifemedium.com/), in which he said that mediumship seems to involve the spirits searching the memory banks of the medium and the sitter in order to find the nearest match for a particular idea they wish to get across. He compared it to combing through an index of images and words and experiences, in search of the closest "fit" to what the communicating entities want to express.

Okay. Now let's see if we can put these two things together and come up with some explanation for the strange mix of accurate and inaccurate perceptions in out-of-body experiences and related phenomena.

We'll begin at the beginning – with the nature of reality. Let's imagine that the reality we see around us is only a construction put together out of the raw materials of a deeper reality, much in the way that a hologram is constructed out of the information encoded in the wave-interference patterns preserved on a holographic plate. This is physicist David Bohm's theory, which he developed at length. Like any analogy it is imperfect, but it does have its interesting features.

A hologram is created when a focused beam of light passes through (or reflects off) the holographic plate. In Bohm's theory, consciousness plays the role analogous to the light beam. Consciousness decodes the encoded data and constructs a multidimensional space-time reality out of it.

One interesting thing about holographic plates is that a very large number of wave-interference patterns can be superposed on the same plate. Which pattern is decoded depends on the angle of the light beam. A shift in the light beam can construct a new image. (This theory and its implications for psi phenomena are discussed at length in Michael Talbot's The Holographic Universe.)

Now let's say that the amount of information that our consciousness decodes is normally limited by the built-in restrictions of the central nervous system. Since the central nervous system has limited capacity, and the information must be "piped through" it in order to allow us to function in the physical world, there is a sharp limit to how much we can perceive of the world around us.

But in an out-of-body experience, consciousness is set free of the body and is no longer restricted by the constraints of the nervous system. Thus, vastly more information can be decoded and passed along to the mind. (For our purposes, consciousness is what perceives, while the mind is what labels and conceptualizes.)

Not only does extracerebral perception entail much more information than consciousness normally processes, but it is possible that consciousness, liberated from the body, may roam more freely "across the dial," so to speak. Varying our analogy for a moment, body-restricted consciousness is locked in, for the most part, to a particular channel on the radio spectrum, while bodiless consciousness can pick up other frequencies.

These other frequencies correspond to the superposed wave inference patterns in the holographic plate. That is, consciousness ordinarily is directed at a specific angle that constructs a certain specific hologram. But out-of-body consciousness is free to explore other angles of view and to construct other holograms that are normally outside our range of perception.

Now, if this is anything like the true situation, then we would expect to encounter some problems in out-of-body experiences and related phenomena. During these experiences, consciousness will be decoding enormously more data than usual - data gathered not only from its regular plane of perception, but from adjacent planes, as well. Many of these new data will be unfamiliar, difficult to label and categorize. This will inevitably lead to errors as the mind struggles to integrate unfamiliar data/impressions into the overall picture.

Thus, consciousness may pick up something of a particular shape which the mind cannot identify. The mind finds the nearest match or fit for this impression, and the nearest match is a barbecue. The mind then chooses to identify the perception as a barbecue in the neighbor's yard, and to really "see it" that way, even though there is no barbecue.

Or for instance, consciousness may detect an aura around the body, but the mind, unaccustomed to seeing auras, chooses to see it as long johns covering the body.

Where consciousness detects what is familiar and expected, there is no error. Where it detects something unfamiliar and difficult to integrate, it seeks a match. This match may be wrong.

In near-death experiences people may see Jesus or Hindu deities; conceivably a dying child could see Santa Claus; in his book The Golden Ass, the Roman writer Apuleius relates the story of his entranced vision of the goddess Isis. We need not believe that consciousness is literally perceiving these things – that Santa or Isis is actually real. Consciousness is perceiving something unfamiliar, and the mind matches it to the nearest item in the mental catalog. Different people have different catalogs, different image sets to choose from. It's almost like doing a Google image search under different search parameters. The parameters you set will determine the matches you get.

For this reason, Buddhists warn us that what is perceived -- whether in ordinary life, in trance, in out-of-body experiences, in near-death experiences, or in death -- is to some extent a product of our own preconceptions. The mind matches unfamiliar data to their nearest familiar analogs from the mental memory banks.

We do this even in regular life when we encounter something "unprocessable." Someone seeing a UFO in the Middle Ages might have seen it as a floating castle or a flying dragon. Today we would probably see it as a spaceship. Something is being perceived, but if it is outside normal categories of thought and perception, we reduce it to a familiar, easily labeled idea/image. And we really do "see it" that way. We can even photograph what we see. The photograph itself is just another thing that we see and is processed by the mind in precisely the same way.

With vastly more information to process in extracerebral perception, and with access to entirely unfamiliar realms, the chance of making errors of this type is greatly increased. Note, too, that perception includes all modalities, not just sight. Our entire experience is a stream of perceptions mediated by familiar categories of thought. When bafflingly unfamiliar elements intrude into the experience, we have a tendency to reduce them to the familiar. In short, our mind makes errors because it is unable to properly integrate the new perceptions. The experiences are real, but they vary according to the interpretation of the individual mind.

Or maybe not. It's just an idea ...