Select your localized edition:

Close ×

More Ways to Connect

Discover one of our 28 local entrepreneurial communities »

Be the first to know as we launch in new countries and markets around the globe.

Interested in bringing MIT Technology Review to your local market?

MIT Technology ReviewMIT Technology Review - logo


Unsupported browser: Your browser does not meet modern web standards. See how it scores »

{ action.text }

Emergent Properties
How do we fight ourselves free from this tangle of circular definitions and misleading pictures? Two ideas seem to me especially helpful in explaining our sense of consciousness as a realm apart. The first is that of an emergent property. Mental states generally, and conscious states in particular, can be seen as emergent states of organisms. A useful analogy is the face in a picture. When a painter applies paint to a canvas, she creates a physical object by purely physical means. This object is composed of areas and lines of paint, arranged on a surface that we can regard, for the sake of argument, as two dimensional. When we look at the painting, we see a flat surface, and we see those areas and lines of paint, and also the surface that contains them. But that is not all we see. We also see a face that looks out at us with smiling eyes. In one sense, the face is a property of the canvas, over and above the blobs of paint; you can observe the blobs and not see the face, and vice versa. And the face is really there: someone who does not see it is not seeing correctly. On the other hand, there is a sense in which the face is not an additional property of the canvas, for as soon as the lines and blobs are there, so is the face. Nothing more needs to be added in order to generate the face – and if nothing more needs to be added, the face is surely nothing more. Moreover, every process that produces just these blobs of paint, arranged in just this way, will produce just this face – even if the artist herself is unaware of the face. (Imagine how you would design a machine for producing Mona Lisas.)

Maybe consciousness is an emergent property in that sense: not something over and above the life and behavior in which we observe it, but not reducible to them either.

The second helpful thought is one first given prominence by Kant and thereafter emphasized by Fichte, Hegel, Schopenhauer, and a whole stream of thinkers down to Heidegger, Sartre, and Thomas Nagel. The idea is to draw a distinction between the subject and the object of consciousness, and to recognize the peculiar metaphysical (Wittgenstein would say grammatical) status of the subject. As a conscious subject, I have a point of view on the world. The world seems a certain way to me, and this seeming defines my unique perspective. Every conscious being has such a perspective, since that is what it means to be a subject rather than a mere object. When I give a scientific account of the world, however, I am describing objects only. I am describing the way things are, and the causal laws that explain them. This description is given from no particular perspective. It does not contain words like “here,” “now,” and “I”; and while it is meant to explain the way things seem, it does so by giving a theory of how they are. In short, the subject is in principle unobservable to science, not because it exists in another realm but because it is not part of the empirical world. It lies on the edge of things, like a horizon, and could never be grasped “from the other side,” the side of subjectivity itself. Is it a real part of the real world? The question begins to look as though it has been wrongly phrased. I refer to myself, but this does not mean that there is a self that I refer to. I act for the sake of my friend, but there is no such thing as a sake for which I am acting. (The parallel illustrates Wittgenstein’s view of these puzzles as essentially grammatical.)

We can relate to conscious creatures in ways that we cannot relate to objects. Their behavior is the outcome of the way things seem to them and can therefore be altered by altering the way things seem. Giving them “food for thought” or – in the case of more primitive animals – “food for perception” and “food for belief,” we also bend them to our purposes. Because they feel pleasure and pain, they can be rewarded and punished and so taught to behave in new ways. Everybody who has trained a dog or a horse in even the simplest task knows that consciousness is an essential intermediary in achieving the final result, and that there is nothing puzzling about this at all: consciousness is as much a part of the behavioral repertoire of the animal as eating and excreting. It consists in a set of functional connections between world and behavior, of a kind that leads us to identify a “point of view,” a “way things seem” that distinguishes the creature with which we are dealing. This point of view is also the quickest and easiest channel to the springs of its behavior.

In referring to behavior, we don’t have to accept the old behaviorist theory that mental predicates can simply be reduced to behavioral syndromes. When we interpret behavior as the expression of a conscious state, we are expressly situating it in an intuitively understood nexus of causal relations. The behavior of a man in pain is only superficially like the behavior of an actor who is pretending to be in pain. The sufferer really cannot stand on his injured leg, and the leg really is injured; the actor’s behavior is voluntary, the sufferer’s involuntary. And so on. All those judgments are hypotheses concerning the functional connections between world and behavior, and they form parts of a spontaneous theory that some philosophers have called “folk psychology.”

Now, there are certainly “neuronal correlates” of consciousness, so understood: namely, all the electrical processes that are necessary to generate conscious behavior (among which, according to Koch, gamma waves – oscillations recorded by an electroencephalogram in the 30- to 70-hertz domain – are particularly important). Some animals exhibit these processes; some (insects, for instance) don’t. To discover the source of these processes is, in a sense, to discover the seat of consciousness in the brain. But does this bring us any nearer to knowing what consciousness is? Suppose you came across a person who behaved and talked as you did, who related to you in all the ways that people relate to each other, and who one day – to your astonishment – unzipped the top of his head to reveal nothing save a dead kitten and a ball of string. Scientifically impossible, perhaps. But logically possible, and giving no grounds at all to deny that this person was conscious.

0 comments about this story. Start the discussion »

Tagged: Biomedicine

Reprints and Permissions | Send feedback to the editor

From the Archives


Introducing MIT Technology Review Insider.

Already a Magazine subscriber?

You're automatically an Insider. It's easy to activate or upgrade your account.

Activate Your Account

Become an Insider

It's the new way to subscribe. Get even more of the tech news, research, and discoveries you crave.

Sign Up

Learn More

Find out why MIT Technology Review Insider is for you and explore your options.

Show Me