by Lyle Lofgren
November 16, 2008
[Note: This is an approximation of a talk I gave at the Dakota County Unitarian-Universalist Church, Burnsville, Minnesota. The footnotes are references only; you don't need to scroll down for them.]

I first became interested in the question "what is reality?" years ago, when I overheard two women talking about a third. "Haven't you noticed?" said one of them. "She doesn't even know what reality is."

But the only way any of us can tell anything about reality is through our nerve impulses. Traditionally, there are five senses: sight, smell, hearing, taste and touch. There are actually many more. The sense of touch, for example, includes information on pressure, temperature, pain, itching, moisture, plus lots of other sensations. At the same time, these nerve impulses contain only rudimentary information. Nerve impulses from the eye, for example, mainly contain information about edges, and you can't tell what the impulses mean by measuring them. The brain (and by this I mean the entire sensory system, including both the central and the peripheral nervous system) interprets these impulses into our perception of reality.

The brain exhibits at least three traits (for want of a better term) when interpreting reality. Each of them evolved because of importance to our ancestors' survival. Each trait has its own pathologies that appear under certain conditions.

At the pre-conscious level, the brain integrates all the sensory nerve impulses into a best guess as to what's happening. Atul Gawandi, a professor of surgery at Harvard, writes:
The mind integrates scattered, weak, rudimentary signals from a variety of sensory channels, information from past experiences, and hard-wired processes, and produces a sensory experience full of brain-provided color, sound, texture and meaning...Perception is inference1.

The article goes on to describe the main pathology due to the Best Guess Trait: the phantom limb phenomenon. No nerve impulses arrive from the missing limb, so the brain invents them: pain, itching, sometimes the impression of wetness, etc.

The brain makes its best guess about reality by ignoring most impulses in order to focus on what it believes is the most important aspect of reality. As George Eliot wrote in Middlemarch:
If we had a keen vision and feeling of all ordinary human life, it would be like hearing the grass grow and the squirrel's heart beat, and we should die of that roar which lies on the other side of silence. As it is, the quickest of us walk about well wadded with stupidity2.

An example we've all experienced is the ability to ignore pain in a crisis. If you have to respond to an emergency at the same time you cut your finger, it doesn't start to hurt until the crisis has passed. Your brain is performing triage all the time.

Some of the pathologies of the Focus Trait are part of what we regard as our normal condition. Everyone knows that our emotional state determines and distorts our perceptions. In addition, the focus trait itself can mislead you. There's a video of a basketball scrimmage that's sometimes shown during training sessions. You're told to count the number of passes made between the players. Most people can count the passes correctly, but nobody notices that there's a guy in a gorilla suit dancing around among the players. If you're told about it and look at the video again, you notice the gorilla, but you are no longer able to count the passes3.

Another normal pathology is Willful Ignorance: you ignore data that doesn't fit your preconceptions, and give too much attention to information that does fit.

Two examples of abnormal pathology of the Focus Trait are obsessive-compulsive disorder (over-focusing) and inability to focus, due to hyperthyroidism, some recreational drugs, and perhaps some forms of autism: the nerve impulses are not screened, and the cacophony becomes overwhelming.

[NOTE ADDED 3/27/2010: The Brain's Dark Energy, by Marcus E. Raichle, in the March 2010 issue of Scientific American (p. 47), quantitatively describes data compression used by the brain: The resolution of the human eye is such that the equivalent of 10 billion bits per second of information strike the retina. The retina has only about a million cells, and so only 6 million bits per second make it to the optic nerve. After passing through the lateral geniculate nucleus (LGN), Only 10,000 bits per second get to the visual cortex in the brain. By the time the image arrives at our consciousness, it contains less than 100 bits per second. If a JPEG or MP3 file were similarly compressed, we'd be able to make no sense whatever of it.

But the LGN is not just a filter that can be described in electrical engineering terms. It connects to many other parts of the brain, so the filtering is based on pattern recognition based on memories of past experiences.]

Once the brain has applied its Best Guess and Focus traits, it is convinced that its construct of reality is complete.

The pathologies that accompany this trait are all normal pathologies. One example is the visual blind spot where the optic nerve enters the retina. You are not normally aware of it, but it can cause you to pull out in front of a car that should have been obvious.

Another example is that humans have always invented supernatural explanations for effects due to invisible causes, or that are caused by mechanisms we don't understand: the so-called "God of the Gaps."

The Best Guess Trait helped our ancestors because most events recur, so they could take advantage of past experiences.

The Focus Trait is useful because too much information can lead to confusion, which causes inaction while you're trying to figure out what to do. Focus is useful if you encounter a tiger in the woods.

The Completeness Trait also suppresses confusion. You don't waste time wondering what you're missing. Of course, inaction due to confusion is fatal if you encounter the tiger, but so is inaction caused by failure to notice it. Therefore, it's hard to understand how this trait, the strongest of the three, evolved. Perhaps the brain needs the Completeness Trait, in spite of its drawbacks, in order to focus.

As soon as you're born, your individual reality is modified into social reality. We learn from others what to notice and what to ignore. That's a good evolutionary strategy, because individual experience can now extend across the generations. Language is a powerful tool of social reality. For example, each individual's sense perception of the color green is undoubtedly different, but most of us have learned to agree on the portion of the visual spectrum called green. Even colorblind people learn to identify some colors by noticing relative brightness. Social Reality reinforces all of the individual Brain Traits, and also, under some conditions, their pathologies.

The apostle Paul wrote: For now I see through a glass, darkly ... 4

He thought that, in heaven, all would be revealed and he would see everything clearly. He never came back to tell us whether or not that's true.

The Hindu religion posits Maya, the Goddess of Illusion. Her function is to hide the Cosmic Spirit (whatever that is) from us. Maya is neither true nor untrue. The Cosmic Spirit is the only truth, so Maya can't be true. But she presents to us the material world, so when you stub your toe in the dark, you know Maya can't be untrue. The Hindus say that, if you think you're sensing the Cosmic Spirit, you're really sensing its reflection off Maya's invisible face.

Maybe the most famous of the old observations about misreading reality is Plato's Parable of the Cave5. The cave is populated by prisoners who can't leave and can't look outside. All they can see are shadows cast on the wall of the cave. The prisoners note regularities in the appearance of the shadows, and, by comparing observations, agree on the nature of reality. But they're only shadows, not REAL reality.

We use the word reality to describe all kinds of aspects of our environment. Recently, we've paid a lot of attention to Political Reality, which is a type of Social Reality. There's Biological Reality, which strongly governs a lot of our actions, and sometimes takes over the Focus Trait: if you have a root abscess, all the world's a toothache. I previously mentioned Emotional Reality, which determines what we perceive. Psychological Reality may or may not be different from Emotional Reality. And so on and so on...

I'm mainly going to talk about a type of Social Reality called Scientific Reality, and am going to further limit the topic by talking about Scientific Reality as it's applied in the field of Physics. There are two reasons for this: I majored in Physics, so I'm somewhat familiar with it. Also, Physics promises that, if you furnish enough money for experiments, it will tell you what Ultimate Reality is, a complete description of how the universe works, as well as its history and future.

Here's how Science applies the three Brain Traits to form a Social Reality:

Scientific research is not a random search for facts. It normally involves testing hypotheses, and these hypotheses are based on a theoretical framework about the way the universe works. This framework is based on abstract mathematics that makes predictions based on self-consistent logic, which in turn is based on the faith that the universe operates on self-consistent logical principles. Or, as Herbert Westren Turnbull wrote:
Mathematics transfigures the fortuitous concourse of atoms into the tracery of the finger of God6.

But mathematics as an interpretation of reality is a long ways from the Tiger in the Jungle.

Controlled experiments are used to test the hypotheses that are based on the theoretical best guesses. In an ideal experiment, all possible variables are controlled except one, and that one is changed in a controlled manner to determine an input/output relationship. Variables are ignored that are judged to be negligible, a judgment that is based on theory or past experience about likely influences.

The scientific search for Ultimate Reality depends on instruments, because we are trying to sense events that happen too quickly or too slowly, or are too large or too small, to be observed directly. You need telescopes, X-ray microscopes, super-accurate clocks, expensive particle accelerators and sophisticated detectors with lots of blinking lights. These devices convert events we cannot observe into those that we can, and each are designed for a specific measurement. But those devices use operations that cannot be directly observed, are designed by trusted engineers who in turn used trusted design principles that cannot be directly observed. We trust those principles because they've given consistent results in the past, and we have faith that the rules didn't change overnight. But every layer of focused instrumentation between the environment and the observer is a new Maya, with its own set of illusions.

All those devices have random measurement errors. In addition, it's often very hard to distinguish between instrument error and reality. An example of this confusion is the detection of Cosmic Background Radiation, discovered by Robert Wilson and Arno Penzias of Bell Labs in 1964. They were designing systems for space communications, but kept getting unwanted noise. After great effort to eliminate the noise (including cleaning bird guano off the antennas), they realized that the noise was real: it was coming from the cosmos. This is one of the rare serendipital discoveries where a scientist looks for one thing and finds another. In this case, they weren't even trying to discover something -- they were trying to solve a practical engineering problem.

Despite the protestations by scientists that science yields only provisional knowledge, the urge for completeness is irresistible, and so speculation always outruns the facts. This becomes a pathology in science.

Examples from the past are Phlogiston, which was the substance that caused fire until the discovery of oxygen, and the Aether, which carried light waves until it was discovered that light waves, unlike sound waves, do not need a medium for propagation -- a vacuum works just fine.

Examples from the present are Dark Matter, Dark Energy, and 11-Dimensional Strings, all of which are, in principle, unobservable, but are cobbled together to explain experimental results that don't fit current theory.

Thomas Kuhn7 showed how this cobbling process works, becoming more and more elaborate until someone (usually from the next generation) comes up with a new theory, a Paradigm Shift, that explains all the discrepancies and becomes the new theory that explains it all, leading to new experiments that produce new discrepancies.

Science is a Social Reality because experiments require the repetition of individual observations, which then must be repeated at other laboratories by other scientists using other equipment. All of these observers discard results that don't fit the hypothesis, unless there are too many of them, in which case theorists start looking for a paradigm-shifting theory. Scientific Truth consists of the average of reproducible results.

Some other examples of the Completeness Trait in Physics is the faith that space and time itself must be complete. Faith in the finiteness of space results in expensive searches for the edge of the universe and the tiniest particle. Faith in the finiteness of time gives us searches for the beginning of the universe and speculations on its end. But what if the universe is infinitely large and infinitesimally small, has always existed, and will exist forever? Then the Grand Unified Theory of Everything that physicists are looking for is another example of the Phantom Limb Phenomenon.

Plato's parable continues: one of the prisoners escapes from the cave, and perceives reality. He returns to tell the other prisoners all about it. Reality is a lot brighter than the interior of the cave, though, so he can't see very well when he returns. Since he's stumbling around, the other prisoners regard him as a blind person, so no one believes he could have seen anything. Worse yet, he has no language to describe what he's seen, and if he makes up new words, no one will know what they mean. Mystics have the same problem when they return to reality. And Plato didn't even consider the possibility that the walls of the cave are all there is.

It's common knowledge that Eskimos have X words for snow, where X is some integer between 17 and 32. Actually, that's an oversimplification: Inuit is a polysynthetic language, made up of strings of roots and modifiers, so every sentence is a new word. And we don't have to go as far as the Eskimos to find lots of words for snow. English has such words as flurries, blizzard, sleet, and freezing rain. We have these separate words because the distinctions are important to us -- distinguishing between flurries and a blizzard can mean the difference between life and death.

So why do we have only one word for Reality? Probably because such fine distinctions have no value for survival, so evolution has not prepared us to understand our scientific observations in any meaningful way. We can only truly understand things that aren't too big, too small, too fast or too slow.

Or maybe reality itself depends on the scale, and the different realities aren't commensurable.

Or maybe Ultimate Reality is similar to cancer: a large number of diseases with the same symptoms.

Big Bang theorist Steven Weinberg wrote:
The more the universe seems comprehensible, the more it also seems pointless8.

Taxpayers did not willingly pay for such a conclusion. We can't get our minds around incompleteness or infinity or eternity, so we take comfort from scientific assurances that we live in a closed universe. But there's no comfort to be found by living in a meaningless one.


1. Gawandi, Atul. The Itch (The New Yorker, June 30 2008, p. 63).

2. Eliot, George. Middlemarch., Chapter 20. (1872).

3. Available at several internet sites, such as

4. I Corinthians 13:12 (King James Version)

5. Plato. The Republic, Book VII.

6. Turnbull, Herbert Westren. The Great Mathematicians (The Story of Mathematics, Vol. 1, p. 168. Simon and Schuster, 1956).

7. Kuhn, Thomas. The Structure of Scientific Revolutions. (University of Chicago, 1962).

8. Weinberg, Steven. The First Three Minutes. (Basic Books, 1977).