In another essay (The Realm of the Mind), I described states of consciousness as a series of rooms. In other essays, I implied that the “brightness” of consciousness varies from one species to another. I have also ventured some guesses about what might be happening in sleep (in The Sleep World and More on Sleep). Now I would like to use a model of levels, to link up with my essay Levels of Being, which goes into purely organismic, physiological levels. I would contend that the levels of consciousness are continuous with the physiological levels.

Which model do I really believe? All of the above tentatively, and none of the above definitively. These are “essays”, i.e. attempts, not treatises.

The lowest levels of consciousness are, of course, unconscious, paradoxical though that sounds. The public should never have been surprised at Freud’s “discovery” of the unconscious — it should have always been obvious that many (a majority) of “mental” events (properly defined in the wider sense) are not readily or ordinarily accessible to introspection. The details of the contents of psychoanalytic theory were new, but not the concept of the existence of the unconscious.

Perhaps we should ascribe some parts of this unconscious level to the autonomic nervous system, which controls our breathing, heart beat, blood pressure (through vaso-constriction), hand sweating, digestion, the danger-alarm system, skin temperature, and a host of other phenomena, some of them used in lie detectors (showing that the autonomic and the voluntary nervous systems communicate with each other). These processes and reactions are not under voluntary control, except after strenuous bio-feedback training, and are automatic rather than conscious, except when we turn an especially powerful beam of attention on them.

The next level, also unconscious, is controlled by the spinal chord and the brain stem, i.e. the older parts of the central nervous system, the so-called “reptilian brain”. This includes various reflex arcs (like the knee jerk) that go only through the spinal chord, withdrawing one’s hand automatically from a hot stove, and trying to satisfy basic drives such as hunger, thirst, escape from too much cold or heat, and sex.

The third level is optionally or “facultatively” conscious. It occurs when we have very thoroughly learned, through repeated experience and learning, some (often quite complex) pattern of behaviour. For example, when driving a car, or riding a bicyle, we can mentally go on “automatic pilot” and devote our conscious thought to something else. (This is why we sometimes manage to do several things at once, though perhaps not with top-quality performance.) In driving this may be somewhat dangerous, yet every driver does it, deliberately or not. Normally, we do start paying conscious attention in situations of danger; but if we are too deeply into automatic operation, we may even fall asleep at the wheel, with disastrous consequences.

We, of course, walk automatically — that is an inborn pattern, hard-wired in the nervous system. Riding a bicycle or playing scales on the piano can become automatic in this sense after we have learned it. Playing solitaire card games with simple rules can become automatic and unconscious; I can go through it without thinking, and realize only in retrospect that I have “missed” the whole game, though playing it correctly by the rules.

Habit formation belongs to only a slightly higher category. We use the same or very similar routines in getting up in the morning and going to bed at night, as well as to some lesser extent in our daily waking life. There is a rhythm to our eating and working and socializing, though we try to vary it a bit to make it more interesting. But when it is totally disrupted, as sometimes happens during travel, we feel uncomfortable and it is a strain, because we are called upon to make too many fully conscious decisions. I am sure that is why we feel tired after travel, even if we have been passive passengers, with the bus driver or the air pilot doing all the work.

The next level up is the ordinary fully conscious level, where we (at least feel) we have the freedom to decide what to do. Free will may be real or an illusion, but it is at least a very powerful illusion. As someone said when asked “Do you believe you have free will?” “Of course I do, I have no choice.” In yet another essay (“Speculations on Free will”), I ventured some guesses on what the physical basis or real free will might be.

Here the voluntary nervous system, and specifically the newer parts of the brain, are fully in charge. We not only feel that we control the efferent function (muscle action), but can fully introspect and interpret the afferent physical signals from the sense organs — really pay attention to what we see, hear, touch, taste and smell. We fully “take in” the experience, become “sensuous” in the non-sexual sense. Such full attention registers especially well in memory. On my recent visit to my native city, I was so “turned on” to the experience that the images keep coming back to me now at odd times, unbidden, when I am doing something quite unrelated. “Memories are made of this” (as the song goes), of things experienced with particular intensity.

I have no direct knowledge of higher consciousness, but it is reliably reported to exist. I picture it as being like coherent laser light in comparison to the ordinary out-of-phase light of consciousness – scattered and “bucking like a wild horse”, as someone said, in advising how to tame it during meditation. Sharpened vision (illumination or enlightenment) on the afferent side would match certain increased abilities on the efferent side, mainly a widening of the extent of freedom of the will, increasing the ability to influence events in the external world.

There may be possibilities beyond this, but that is scary. In the science fiction story “Childhood’s End”, the author implies that the “total breakthrough” which he describes is facilitated by being under the direction and supervision of the devil. The new super-abilities include the overcoming of limitations of space and time, and the ability to overrule the operation of natural laws. It means that we stop being human and are transformed into some totally different beings.

I fervently hope that this last level does not exist.