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The Miracle of Consciousness


The understanding of cognition is very much a work-in-progress. I'm not an expert but I will try to communicate some results that are philosophically satisfying and useful in situations we encounter every day.  They help to clarify the meaning of concepts like "understanding" and "awareness" and to dispel the mystery that leads to magical thinking and supernatural mythology.  And they help us to appreciate the miraculous character of our everyday experience.

Consciousness is - A dynamic, creative, open-ended process to build an internal representation of reality,  that seems to be stable but is actually made up of many dynamic processes.

We use sensory input, pattern recognition, fill-in-the-blanks from memory of past experience, and extrapolation from knowing unseen parts of objects and knowing what to expect from our surroundings and from our own efforts.

In retrospect, a few leading lights have shown clarity, for example,  William James, about 1890, wrote "Consciousness is a process, not a thing."

Is the time you get up in the morning a thing?  No, that's sloppy thing-king!  Any-thing we can name must be a thing?  No - We can name ideas and processes!  And - they exist, but in a very different way from things!

In this decade the tools have finally become available to dig out the details of brain functions.  Functional MRI (Magnetic Resonance Imaging) and PET (Proton Emission Tomography) can localize the neurological activity associated with brain functions that are called forth in psychological or pharmacological experiments.  In past years that information was only available by chance, from studying patients with localized brain damage.  And the detailed functions of individual nerve cells could only be explored by micro-manipulation of electrodes during radical surgery of experimental animals or lower life forms.  Now new results are reported every day.

And we now have the logical and philosophical sophistication that comes from our experience of programming electronic computers to do complex data-processing tasks.


The computer, so far, is a tool that depends on the precise execution of stored instructions, at great speed, with no originality.  For example, a GPS receiver like you might have in your car, can calculate from the timing of satellite signals, its location anywhere on earth, and display a map showing your position.  It uses a mathematical model of the satellite orbits and radio propagation.  And we can model the motions of our atmosphere and calculate tomorrow's weather from today's observations but the task is so extensive that it takes many computers operating in parallel, on localized bits of the problem, to be of any use.

Our brain is a massively parallel computer system that models our reality.  In fact all our bodily processes are self-motivated parallel systems which function as they must and we are aware of them only when they need our attention.

When we catch a fly ball in a baseball game we are modeling the physics of gravity and air resistance to judge where we must be when it comes down.  But we don't use numbers and mathematical equations to do it.  We use our visual and kinesthetic senses and our remembered past experience to elicit the muscular effort to adjust our position appropriately.

So how do we do that?

Our Central Nervous System, including the spinal cord, brainstem, cerebral hemispheres, optic nerves, and retina of the eyes, contains about 100,000 million neurons.  These are cells specialized for signaling, and they each connect with about 1000 other neurons.  They function in parallel, each working at its own pace, so we can't possibly be aware of all that they do.

Neurons have a cell body, which contains the nucleus and where most of the cell's metabolic functions are located, and input fibers called dendrites, and an axon, a long fiber where the all-or-nothing output signal is conveyed to other neurons or to muscle cells that contract when stimulated.  The connection to another neuron or muscle cell is called a synapse, a microscopic button that is specialized to release chemicals called neurotransmitters which either stimulate or inhibit the cell they connect with.  Both axons and dendrites may extend for some distance and may be branched to connect with many other cells.

Every neuron is a little decision-maker.  The cell membrane acts like a chemical battery, maintaining a several-millivolt potential difference between inside and outside.  When the neuron is stimulated, by an appropriate combination of input signals, a process occurs that allows potassium ions and sodium ions to penetrate the membrane, which is like short-circuiting the battery.  This produces an impulse of millivolts, that lasts several milliseconds, which propagates along the nerve fiber at hundreds of feet per second.  Then the system recovers to repeat a few hundred times a second.

After early childhood nerve cells ordinarily do not reproduce, but the synapses are reinforced or attenuated depending on their activity.  By this means clusters of nerve cells become specialized according to the inputs they receive, from sensory organs, from surrounding or distant neurons, and from positive or negative feedback from near and far in the brain.  Thus they are constantly combing their connections for combinations that are significant, and reinforcing those that turn out to be useful.

So we, and other animals, have evolved the associative capability for pattern recognition, which becomes the basis for memory because related inputs can restimulate patterns from previous expenence.

This pattern recognition process starts in the sensory organs.  For example the retina of the eye contains the rod and cone cells which are stimulated when light quanta are absorbed by the photopigments they contain, and also associative neurons that connect with various combinations of surrounding cells.  The million axons that go to the brain through the optic nerve are triggered by various combinations of contrast in the optical image projected by the lens from the outside world.  They represent edges and orientations and motions and color contrasts in the visual image, and they are routed to different areas of the cerebral cortex to be recognized as features of the visual scene.

The process of constructing a visual scene in our brain from these inputs is quite sophisticated using elements from the areas that process the abstracted optic nerve signals and relying on automatic eye motions to fill in blanks in the retinal image.  In fact blood vessels in the eye pass in front of the retina, and there is a large blind spot where the optic nerve exits.  And the color-sensitive cone cells are crowded only in a small area called the fovea, where we see with high resolution.

Thus our brain incorporates a built-in system for working around the deficits in our vision and presenting a picture of reality that seems stable in spite of eye movement, with resolution everywhere as good as fovial vision.  We can always fill in the blanks by glancing in another direction so it's OK to think that our vision is better than it really is.

So with layer upon layer of simple pattern recognition elements we create an "imagined present" incorporating object/background discrimination and using motion and binocular parallax to give depth perception and incorporating what we know from past experience of familiar objects.

Similar abstraction and reconstruction occurs with the other senses - we need motion to sense touch and body position, and we sense pitch intervals of tones better than absolute pitch.

And so - to our associative pattern-recognition system an object is like a song.  A few familiar notes remind us of a whole definitive performance.  And from recognizing a few features of an object we imagine the whole thing, in its generic form that fits the features in their place.

And the most vital senses are those that change with time - moving objects or sound patterns, or our own bodily motions.  We can extrapolate, from our remembered experience and sensory inputs, and imagine where that fly ball will come down and how to propel ourselves to be there to catch it. Imagination is modeling, of real or potential events, which is easy with the massively parallel pattern- recognition elements of our cerebral cortex, and awkward with the serial execution of sequential program steps in a digital computer.

Thus our perception of our present situation is a dynamic, creative process - using the scientific method - where we construct a hypothesis about what's happening and compare with developing reality.  We fill in the blanks by glancing where we need-to-know and revise our estimate, forgetting whatever was wrong in our world-view.  So we are only aware of the result and the pattern-recognition processes are unconscious, self-propelled parallel processing by the billions of living neurons, each doing its own thing.

With that introduction we can now look at some details of what's known about the working brain.  I'll try to fill in some broad outlines without getting lost in detail.

Humans are the result of biological evolution along with the many life forms on Earth today and in the past.  We share the basic biochemical functions of cellular existence with bacteria and with most other life forms.  We share the basic functioning of our nervous system with the chordates, that include some microscopic worm species, fish, and amphibians, reptiles, birds, and mammals of today.

But we have evolved a particular part of our brain, called the neocortex from its recent evolution, way larger than any other animal.

This cortex is the "grey matter" which is the about-two-millimeters-thick outer layer or rind of the large hemispheres that surround the midbrain anatomy at the top of the spinal cord. It has about the area of a large dinner napkin but it is crumpled to fit inside the skull.  The major folds divide the lobes of the brain - frontal, temporal, occipital, parietal - and the left and right hemispheres are separate except for a bridge of fibers called the corpus callosum, and two small commisures.

Microscopic examination of the cortex shows several varieties of neurons, with the outer layer consisting mainly of axon and dendrite fibers that communicate with other neurons near and far.  The inner layer is devoted to sending and receiving signals to and from the midbrain region.

The "white matter" beneath the cortex is a solid mass of myelinated nerve fibers that connect to the midbrain structures that evolved long before the neocortex.  These structures appear to be involved in sleep and arousal, and in regulating the activity of the cortex but not in the actual pattern recognition. They play a critical part in the control of other functions, like attention, emotion, mood, motivation, and movement. The reticular formation in the midbrain stimulates the motor cortex to produce the state of wakefulness called "consciousness".  Damage here can produce a coma, or deep unconsciousness.

The connecting fibers go both ways and provide value-judgement feedback to control attention and long-term memory.  Those details are being explored with functional imaging experiments but they are outside the range of this presentation.  (Show Science Magazine 18 Feb 05)

To explain feedback we need to jump back to electrical engineering.  In the 1930's vacuum tube amplifiers were used to amplify audio signals from microphone or phonograph pickup, to drive a loudspeaker to reproduce the sound.  But the sound was distorted because the output current was not exactly proportional to the input voltage waveform.  In the 1940's this was corrected by using "negative feedback".  The input signal was compared to a sample of the output, and the amplifier was driven by the difference.  With a high-gain amplifier the output was driven to make the difference very close to zero, so the output was made accurately proportional to the input in spite of distortion in the amplifier.  This design feature has been standard practice ever since, and we now recognize it when we see it in natural systems.

You may be familiar with feedback in another context. The internet auction program E-Bay asks both buyer and seller for feedback after a transaction and it accumulates a composite rating for both participants, over their whole history of participation. These ratings are publicly available to facilitate improved judgement about reliability of anonymous trading partners.

And we use feedback all the time. We watch what we are doing and adjust our muscular effort to do what we want to do.  Our mental image of the motion is compared with reality and we minimize the difference.  "Wishing will make it so!"

The dynamic selection in our cerebral cortex of patterns that are significant, and the hierarchical selection of patterns of patterns of patterns that are related, is a feedback process that facilitates a richness of memory and imagination that is so massive that we can only use a bit of it at a time.

So our awareness is a stream-of-consciousness, one-thing-at-a-time, concentration of attention that leaves most of our mental faculties out-of-sight.  But they are there, available as needed.
Doing a crossword puzzle is an example of associative memory performance that is unconscious.  It's a miracle that words which fit appear in our mind without rational, sequential, "reasonable" thought!  In fact we must consciously clear our mind of rational thought to succeed.

So - The human animal has evolved with a mental capacity that has made us masters of the world, whether we want to or not.  The breakthrough achievement that makes us "better" than all the other animals is language capability.  The survival value of communication has enabled the rapid evolution, in under 100,000 years, of our capability to mold the environment to our needs and to overpopulate the Earth.

Another digression into the technology of communication - In the 1930's telephone and radio engineers were recognizing the relation of data rate to bandwidth.  A unit of data was defined, the binary digit, or "bit".  It was understood that a radio channel needs a ten kilocycle-per-second bandwidth and a television channel needs a ten megacycle-per-second bandwidth, about 1000 times as much. Why? Because a sound wave is a single sequence of air pressure changes which can be communicated by a serial presentation of data. Projecting or viewing a picture requires the simultaneous or parallel transmission of brightness values for every point in the image.  The television camera is a parallel-to-serial data converter because it scans and transmits every point in the image sequentially, thirty times a second.

Incidentally, much of that data is redundant, because consecutive frames have pictures that are almost alike.  Contemporary digital television economizes by transmitting only the differences of each image from the one before. Remember the optic nerve?  Each fiber responds to differences of light intensity on nearby sensitive cells, representing features of the visual scene.  This is a data compression technique, transmitting only what's important for the brain to make its reconstruction.

Our use of language involves much more than the ability to give meaning to symbols as is popularly supposed.  It requires the rapid retrieval from memory of a series of sound patterns and the capability to express them with our vocal anatomy.  But more than that, it requires choosing, from a multitude of possibilities, the ideas we want to communicate and the words to express them in the grammatical arrangement that a listener can understand.  In the computer world this is called parallel-to-serial conversion.  And the listener does a serial-to-parallel conversion to interpret the sound sequence as words, with meanings that depend on context, retrieved from among many possible interpretations. And if it's a new idea the listener will store it in an associative memory that links it to other related ideas for easy recall.

For example the same words might have very different meanings.  Remember a song that ends:  "And nothing will stop the Army Air Corps!"  Does that mean that they can be stopped by nothing?  No, just the opposite, but our language is full of ambiguities that we never notice because our sophisticated language faculty interprets in context.

It's amazing that a single-channel medium of communication, with only a few syllables-per-second data rate, can be so expressive.  Credit the massively-parallel pattern recognition machine that is our cerebral cortex.

Incidental to the survival value of language for communication, the necessary mental sophistication brought other benefits. We had to be more explicitly aware of our own thoughts to explain them to others, and we had to be self-conscious in a new way.  We had to see ourselves as others see us, in order to express ourselves so they could understand.  And we could develop a culture of common knowledge that was more reliable because it was tested and revised by many people.  The scientific method could become an explicit cultural artifact, as well as an unconscious part of our everyday awareness.

But now our "awareness" of rational thought is cast in the mold of verbal communication, explaining ourselves to others.  We think of "understanding" as a step-by-step, cause-and-effect explanation.  We don't give credit to the unconscious part of our mental processes, the intuition and imagination and the creativity.  We need to rationalize everything we do because we don't trust ourselves unless we can offer a verbal explanation.  So our awareness of knowledge is framed that way.

So - if all we know is what we think, then of course we think we know it all!

The creation of new connections - new awareness, new ideas, new possibilities, is the miraculous result of the massively parallel pattern recognition machine, that we have always lived with and taken for granted.  So - the creation of new thoughts that represent something in reality - actual or potential - is such a familiar experience that it is easy to believe in miracles in the real world.

But we don't need the mythology, except to treasure the subtlety of our heritage.  We should take credit for our own creations.

I'm reminded of a song from a 1939 movie, a favorite of my third-grade teacher, that I thought at the time was unrealistic nonsense.  But now I realize that it expresses the experience that is part of everything we do, the feeling of motivation that is part of the self-regulating system we use to guide our efforts to accomplish whatever we want, from bodily motions to acts of creation.


Wishing will make it so!                                                                      From Love Affair (De Silva 1939)

Wishing will make it so.
Just keep on wishing and cares will go.
Dreamers tell us dreams come true, it’s no mistake.
And wishes are the dreams we dream when we’re awake.
The curtain of night will part, if you are certain within your heart.
So if you wish long enough, wish strong enough, you will come to know
Wishing will make it so.
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