This is a draft (July 28, 2005) of Chapter IV of The Emotion Machine by Marvin Minsky. Please send comments to minsky@media.mit.edu

Chapter 4. CONSCIOUSNESS

 

§4-1. What in the world is Consciousness?

 

“No philosopher and hardly any novelist has ever managed to explain what that weird stuff, human consciousness, is really made of. Body, external objects, darty memories, warm fantasies, other minds, guilt, fear, hesitation, lies, glees, doles, breath-taking pains, a thousand things which words can only fumble at, co-exist, many fused together in a single unit of consciousness”— Iris Murdoch, in The Black Prince. 1993.

 

What kinds of creatures have consciousness? Does it exist in chimpanzees—or in gorillas, baboons, or orangutans? What about dolphins or elephants? Are crocodiles, frogs, or fish aware of themselves to any extent—or is consciousness a singular trait that distinguishes us from the rest of the beasts?

 

Of course, those animals won’t answer questions like, “What is your view of the nature of mind.” But when we interview mystical thinkers who claim to know what consciousness is, their replies are seldom more enlightening.

 

Sri Chinmoy 2003: “Consciousness is the inner spark or inner link in us, the golden link within us that connects our highest and most illumined part with our lowest and most unillumined part.”

 

Some philosophers even insist that no one has better ideas about this.

 

Jerry Fodor 1992: "Nobody has the slightest idea how anything material could be conscious. Nobody even knows what it would be like to have the slightest idea about how anything material could be conscious. So much for the philosophy of consciousness."

 

Is consciousness an all-or-none trait that has a clear and definite boundary?

 

Absolutist: We don’t know where consciousness starts and stops, but every object must be conscious or not—and, clearly, people are conscious, while rocks are not.

 

Or does consciousness come in different degrees?

 

Relativist: Everything has some consciousness. An atom has only a little of it, while brains can have it to greater degrees—and perhaps there are no limits to it.

 

Or is that question still too vague to justify trying to answer it?

 

Logicist: Before you go on about consciousness, you really ought to define it. Good arguments should start right out by stating precisely what they are about. Otherwise, you'll begin with a shaky foundation.

 

The Logicist’s policy might seem 'logical'—but, although we don't like to be imprecise, a clear definition can make things worse, until we’re sure that our ideas are right. For, consciousness is one of those suitcase-like words that we use for many types of processes, and for different kinds of purposes. It’s the same for most of our other words about minds, such as awareness, sentience or intelligence.[i]

 

So instead of asking what ‘consciousness’ is, we’ll try to examine when, how, and why people use those mysterious words. But why do such questions even arise? What, for that matter, are mysteries?

 

Daniel Dennett 1991: “A mystery is a phenomenon that people don't know how to think about—yet. Human consciousness is just about the last surviving mystery. There have been other great mysteries [like those] of the origin of the universe and of time, space, and gravity. ... However, Consciousness stands alone today as a topic that often leaves even the most sophisticated thinkers tongue-tied and confused. And, as with all of the earlier mysteries, there are many who insist—and hope—that there will never be a demystification of consciousness.”

 

Indeed, many of those who ‘insist—and hope’ that consciousness cannot be explained still maintain that it alone is the source of most of the virtues of human minds.

 

Thinker 1: Consciousness is what binds all our mental events together, and thus unifies our present, past, and future into our continuous sense of experience.

 

Thinker 2: Consciousness makes us 'aware' of ourselves, and gives us our sense of identity; it is what animates our minds and gives us our sense of being alive.

 

Thinker 3: Consciousness is what gives things meanings to us; without it, we would not even know we had feelings.

 

Wow! Wouldn’t it be astonishing if any one principle, power, or force could endow us with all those abilities?

 

However, I’ll argue that it would be a mistake to believe in any such entity—because we ought to be asking this question, instead: “Isn’t it remarkable that any single word or phrase could have come to mean so many different things?”

 

William Calvin [1995] and George Ojeman “Modern discussions of consciousness … usually include such aspects of mental life as focusing your attention, things that you didn't know you knew, mental rehearsal, imagery, thinking, decision making, awareness, altered states of consciousness, voluntary actions, subliminal priming, the development of the concept of self in children, and the narratives we tell ourselves when awake or dreaming.”

 

All this should lead us to conclude that consciousness is a suitcase-like word that we use to refer many different mental activities, which don’t have a single cause or origin—and, surely, this is why people have found it so hard to “understand what consciousness is.” The trouble was that they tried to pack into a single box all the products of many processes that go on in different parts of our brains—and this produced a problem will remain unsolvable until we find ways to chop it up. However, once we imagine a mind as made of smaller parts, we can replace that single, big, problem by many smaller, more solvable ones—which is just what this chapter will try to do.

 

∞∞∞∞∞∞∞∞∞∞∞∞∞∞∞∞∞∞∞∞

 

§4-2. Unpacking the Suitcase of Consciousness.

 

Aaron Sloman 1994: “It is not worth asking how to define consciousness, how to explain it, how it evolved, what its function is, etc., because there's no one thing for which all the answers would be the same. Instead, we have many sub-capabilities, for which the answers are different: e.g. different kinds of perception, learning, knowledge, attention control, self-monitoring, self-control, etc."

 

To see the variety of what human minds do, consider this fragment of everyday thinking.

 

 

It might seem natural to ask, "How conscious was Joan of what she did?" But rather than dwell on that ‘consciousness’ word, let’s look at some of the things that Joan actually did.

 

Reaction: Joan reacted quickly to that sound.
Identification: She recognized it as being a sound.
Specification: She classified it as the sound of a car.
Attention: She noticed certain things rather than others.
Indecision: She wondered whether to cross or retreat.
Imagining: She envisioned two possible future conditions.
Selection: She selected a way to choose among options.
Decision: She chose one of several alternative actions.
Planning: She constructed a multi-step action-plan.
Reconsideration: Later she reconsidered this choice.

 

She also did other things like these.

 

Learning: She created descriptions and stored them away.
Recollecting: She retrieved descriptions of prior events.
Embodiment: She tried to describe her body's condition.
Expression: She constructed some verbal representations.
Narration: She arranged these into storylike structures.
Intention: She changed some goals and priorities.
Apprehension: She was uneasy about arriving late.
Reasoning: She made various kinds of inferences.

 

She also used many processes that involved reflecting on what some of those other processes did.

 

Reflection: She thought about what she had recently done.
Self-Reflection: She reflected on what she had thought about.
Empathy: She imagined some other persons’ thoughts.
Reformulation: She revised some of her representations.

Moral Reflection: She evaluated what she has done.
Self-Awareness: She characterized her mental condition.
Self-Imaging: She made and used models of herself.
Sense of Identity: She regarded herself as an entity.

 

This is only the start of a catalog of some of Joan’s mental activities—and if we want to understand how her thinking works, we’ll need to have much better ideas about how each of those activities work and how they all are organized. At various points in the rest of this book, we’ll examine each item on that list and try to break it into parts—to see what processes it might involve. However, to accomplish this, we’ll to begin with some way or ways to divide an entire mind into parts—and our everyday folk-psychology abounds with ideas about dividing the functions of minds into pairs like these:

 

Conscious vs. Unconscious

Premeditated vs. Impulsive
Deliberate vs. Spontaneous
Intentional vs. Involuntary
Cognitive vs. Subcognitive[ii]

We’ll discuss such ‘dumb-bell’ distinctions in 9-2, and will conclude that each such division is simply too crude. For example, the division between conscious and unconscious does not distinguish between information that is inaccessible because one has no way to access it, or because it is actively censored or ‘repressed,’ or because (as Freud suggested) it has been ‘sublimated’ into some form that one cannot recognize—or because one has simply failed to retrieve it (that is, to bring it into one’s active working memory). In any case, this book will argue that little good will come from attempts to divide our minds into only two parts.

 

On the other hand, it would not often help to try to split a mind into too many parts, because that can make it difficult to develop useful principles.

 

We have already seen some useful ways to split a mind into large numbers of different parts—for example, as sets of resources or as collections of rules. However, for making better generalizations, we’ll need a design that has fewer components. Accordingly, every chapter of this book will exploit the idea that a mind is composed of processes that operate on just a few “levels.” Beginning with three such levels will help us to avoid “dumb-bell” distinctions, and the following chapter will argue that we’ll need at least three more, higher, levels of mind. However, the rest of this chapter will mainly focus on the question of why people are so prone to pack so many different concepts into that single “suitcase of consciousness.”

 

∞∞∞∞∞∞∞∞∞∞∞∞∞∞∞∞∞∞∞∞

 

§4-3. A-Brains and B-Brains

 

Socrates: Imagine men living in an underground den, which has an opening towards the light—but the men have been chained from their childhood so that they never can turn their heads around and can only look toward the back of the cave. Far behind them, outside the cave, a fire is blazing, and between the fire and the prisoners there is a low wall built along the way, like the screen that puppeteers have in front of them, over which they show the puppets.

Glaucon: I see.

Socrates: And do you see men passing along the wall carrying all sorts of vessels, and statues and figures of animals made of wood, stone, and various materials, which appear over the wall? Some of them are talking, others silent.

Glaucon: You have shown me a strange image …

Socrates: Like us, they see nothing but only the shadows of themselves and of those other objects, which the fire throws on the opposite wall of the cave… Then in every way such prisoners would deem reality to be nothing else than those shadows...—Plato, in The Republic

 

Can you think about what you are thinking right now? In a literal sense, that’s impossible—because each new such thought would alter the thoughts that you were just thinking before. However, you can settle for something slightly less, by imagining that your brain (or mind) is composed of two principal parts: Let’s call these your A-brain and B-Brain.

Now suppose that your A-Brain gets some signals from the external world (via such organs as eyes, ears, nose, and skin)—and also can react to these, by sending signals that make your muscles move. By itself, the A-brain is a separate animal that only reacts to external events, but has no sense of what they might mean. For example, when the fingertips of two lovers come into intimate physical contact, the resulting sensations, by themselves, have no particular implications. For there is no significance in those signals themselves: their meanings to those lovers lie in how they represent and process them in the higher levels of their minds. (See Pohl 1970.)

 

Similarly, your B-Brain is connected so that it can react to signals that it receives from A, and then can react by sending signals to A. However, B has no direct connection to the outer world so, like the prisoners in Plato’s cave, who see only shadows on a wall, the B-brain mistakes A’s descriptions for real things. The B-Brain does not realize that what it perceives are not objects in the external world, but are merely events in the A-brain itself.

 

Neurologist: That also applies to you and me. For, whatever you think you touch or see, the higher levels of your brain never can actually contact these—but can only interpret the representations of them that your other resources construct for you.

 

Nevertheless, although the B-Brain cannot directly perform any physical actions, it still can affect the external world, by controlling the ways in which A might react. For example, if B sees that A has got stuck at repeating itself, it might suffice for B to instruct A to change its strategy.

 

Student: Sometimes, when I've misplaced my eyeglasses, I keep looking for them in the very same place. Then a silent voice reproaches me, suggesting that I stop repeating myself. But what if I were crossing a street when suddenly my B-brain said “Sir, you’ve repeated the same actions with your leg for more than a dozen consecutive times. You should stop right now and do something else.” That could cause me a serious accident.

 

To prevent such mistakes a B-Brain would need appropriate ways to represent things. In this case, you would be better off if your B-brain represented ‘walking to a certain place’ as a single extended act like, “Keep moving your legs till you get to the other side of the street.”

 

However, this raises the question of how that B-Brain could acquire such skills.[iii] Some could be built into it from the start but, for the B-Brain to learn new techniques, it might itself need similar help—which could come from a level above it. Then while the B-Brain deals with its A-Brain world, that ‘C-Brain’ in turn will supervise B.

 

 

Student: Would not this raise more difficult questions, because each higher level would need to be smarter and wiser?

 

Not necessarily, because that C-brain could act like a “manager” who has no special expertise about how to do any particular job—but still could give ‘general’ guidance like this:

 

If B’s descriptions seem too vague, C tells it to use more specific details.
If B’s is buried in too much detail, C suggests more abstract descriptions.
If what B is doing is taking too long, C tells it to try some other technique.

 

Furthermore, if both B-Brain and C-brain get stuck, we could add yet more levels to our multilayer mind-machine.

 

Student: How many such levels does a person need? Do we have dozens or hundreds of them?

 

Levels, Layers, and Organisms

 

In our earlier chapters, we suggested that our mental resources are organized into at least these levels of processes: