Consciousness is the transcription of just-past actions (either mental or physical) into the narrative that is used to fashion the model of self.
An obvious question for somebody to ask is: “How does that produce consciousness?” (The Why of consciousness was already covered.)
Consider the consciousness (such as it is) of a dog. Its consciousness is different from ours for several reasons. Its brain lacks the high level of specialization we use for processing language. Its most compelling sense — smell — depicts the world in a more inclusive way than our most compelling sense — vision — which tends to put distance between us and that which is being perceived. The dog's sense of the passage of time is also different from ours (though I think dogs could be trained to perceive time in a slightly more human way).
The key factor to bear in mind is that a dog does have experiences. It has senses that sense and can react to the input. It can learn, to some extent, from experience. In these regards it is like us. What a dog does not do (at least, not to the extent that we do) is create a biographic account of its self. For the most part, dogs do not rehearse actions in advance in their heads. For the most part, dogs do not plan ahead.
Now consider the human carrying out the transcription process that I say is the hallmark of (human) consciousness. Human consciousness is not the sensing; dogs can sense. Human consciousness is not the reacting; dogs do that. Human consciousness is not the bringing up of the benefit of experience; dogs do that, too. So where's the difference?
The difference is a question of focus. Picture a large sheet of paper almost entirely illuminated by a soft light. That soft light represents the impingement of the senses and memories. This is the dog's world. It can also be the human's world as seen outside consciousness. It is what the brain uses as input prior to letting the consciousness in on it. (The human memories are, of course, more elaborate than those of the dog's.)
Now, superimposed on that mostly-lit sheet of paper, imagine a slightly diffuse spot of light, considerably brighter than the other illumination. This is your attention. The size and fuzziness of the spot might vary depending on how much your attention is focused.
That spot delineates your consciousness. That is what you take to be you. (It is not you — at least, not in the sense you probably think it is — but you can believe it is.)
Who Controls the Attention?
Now, what determines the focus and direction of the attention? It can be various things, such as induced memories or startle reflex, but none of these are under your conscious control. Some of these may seem to be under conscious control, but this is an illusion (as I explained in Part One).
An “induced memory”, by the way, is a memory that arises because of another event. If I say “elephant” you have a particular memory. I induced you to have that memory; you did not choose to have it. After that memory arises, you might also recall the famous sentence “Don't think of an elephant!” This is also induced, since it arose unbidden.
Moreover, it is a memory that is caused by a train of previous cognition. Much of what we take to be self is actually just a familiar train of thought. That is to say, you recognize it as your thinking and declare it yours. If Thing A owns Thing B, then Thing A must be real — or so goes the reasoning. But of course even constructs (such as corporations) can own things. “Ownership” is a nefarious fiction we've been taught to believe, to our great detriment, but that's a topic for another day.
It is a bit misleading to continue to picture human consciousness in terms of a spot of light on paper. Such a depiction raises questions like, "Where does the light come from?" That's taking the illustration too seriously. (This kind of error tends to lead some people to imagine supernatural levels that are not there.)
To avoid this problem, imagine darkness on the paper instead of light. Instead of the fuzzy spot of light imagine a shadow that is darkest in the middle. If it helps, you can think of this as the hole into which the transcribed actions and context fall on their way into memory.
One advantage of seeing consciousness in this negative way is that it highlights its receptive, non-controlling nature. When it comes to analogies, light seems active, while darkness seems passive.
The Model is Not the Thing
None of these explanations will help if you simply picture the sheet of paper (light or dark). If you try to picture consciousness as an external thing — if you try to model it — you will have the wrong answer. It may feel right, but it will be wrong because it's a model of the thing rather than the thing itself.
Illustrations involving sheets of paper might have some value, but there are probably better ways to attain an understanding of what is being described here. If you have a pet or are otherwise familiar with another mammal, consider how their internal life is different from yours. In some ways they are not so different (which is why my diet is vegetarian, incidentally) but in the differences we can find that which we call human consciousness.
It may be impossible to be directly aware of consciousness, just as we are mostly unaware of our digestion. Nonetheless, we can look within ourselves and find abundant evidence of the process. In neither case can we control the process in an absolute sense, though we can interfere with it. For example, both processes can be interfered with simply by holding one's breath for a while.
Feel free to try it! It may teach you something about how much you actually control.
Part Four of this series of five articles about consciousness can be found here.