Wednesday 22 May 2013

Phenomenal consciousness

An e-mail has just invited me to consider whether phenomenal consciousness is a causally inert epiphenomenon, and a pointless by-product of brain activity. It is the sort of question that can be transformed into a different question.

First, to what does the claim amount?

It is not a claim about self-awareness of the type that underpins an agent's knowledge that the actions that she can make happen just by thinking, are the actions that will take place in her immediate vicinity, and are performed by the entity that must be kept fed in order for her thought processes to continue. That sort of self-consciousness can be characterized as having a grasp of what Perry called the essential indexical. It is the sort of self-consciousness that lies at the heart of Lucy O'Brien's argument in her book, Self-Knowing Agents. It is something that must be represented in our brain cells, one way or another, in order for us to function as we do.

Rather, the claim is about how things feel to us, the qualia (or apparent qualia, if one thinks that there are no qualia) that we have, but that zombies would not have. So the second part of the claim, that phenomenal consciousness is a pointless by-product of brain activity, is a claim that zombies could do just as well as we do. It might happen to be that any creature that functioned as we function could not be a zombie, for example, because we would need to wire up the cells in certain ways which would inevitably produce phenomenal consciousness as a by-product. But even if that were so, the second part of the claim could still be made. It would merely need to be worded as "Disregarding the practicalities of making zombies, they could do just as well as we do".

If, however, one were able to substantiate the second part of the claim, in the form of a claim that zombies could do just as well as we do, that would not mean that we would have established the first part of the claim. (It may be that the second part of the claim could be taken in some other form, such that substantiating it would substantiate the first part of the claim, but it is not obvious how to re-cast the second part in order to give this result.)

We would not be able to move straight from the second part to the first part, because phenomenal consciousness might be causally effective in human beings, creatures who have it, even though an alternative way of achieving the same results that we achieve, an alternative that did not involve phenomenal consciousness, would be available. We should not suppose that the difference between a human being and a zombie is simply the presence or absence of phenomenal consciousness, with no other differences. And if there are other differences, such that we would not get from a zombie to a human being simply by adding phenomenal consciousness, those differences could build in a causal role for phenomenal consciousness.

We need to say something about how phenomenal consciousness could have a causal role. It could be said that only fundamental particles and forces have causal roles. But that would be a very narrow way of speaking. We are more inclined to say that macroscopic objects also have causal roles. Now suppose that a subject has his fingers on some buttons, which carry modest electrical charges that produce a pleasant tingling sensation, but which are also getting steadily hotter. If a particular configuration of brain cells corresponded to a particular feeling in the subject, and could not be picked out in any other way than by saying "this is the configuration when the subject feels heat at his fingertips", and an analysis of his brain processes showed that the configuration led to conscious thoughts about when it would become sensible for him to withdraw his fingers and forgo the pleasant tingling sensation, then it would not be obviously inappropriate to say that the feeling played a causal role, any more than it is inappropriate to say that a ball that rolls off a table and onto the floor plays a causal role in making a noise, rather than saying that the particles of which the ball is comprised play causal roles in disturbing particles in the atmosphere. Berent Enç's thoughts on causation and conditionals, in his book How We Act, are relevant here.

It would not be obviously inappropriate to speak in that way, but it might still be inappropriate. What might make it appropriate, or inappropriate?

A claim of appropriateness would best be sustained by a claim that states of phenomenal consciousness were on a par with macroscopic physical objects. There is a sense in which both are not really there, but are mere causally inert epiphenomena of the fundamental particles and forces. If they were causally inert in the same sense, that would strengthen the position of those who said that it was appropriate to regard states of phenomenal consciousness as more than epiphenomena, to the extent that it was appropriate to regard macroscopic physical objects as more than epiphenomena.

So the new question, into which we can transform the original question, is this: Are states of phenomenal consciousness epiphenomenal on the fundamental particles and forces, in the same way as macroscopic physical objects?

One reason to say that states of phenomenal consciousness and macroscopic physical objects were epiphenomenal in different ways, would be that laws of the same general type, physical laws, give us a grip on the behaviour of particles, and on the behaviour of macroscopic physical objects. It is a debatable claim, but not a crazy claim, that we could derive the whole of chemistry and biology from physics, too. (This is an upwards claim, different from the claim that we could reduce biology and chemistry downwards to physics.) We could claim that any emergence would not obstruct such an upwards derivation.

But then, could one also argue that no emergence would get in the way of an upwards derivation of facts about states of phenomenal consciousness? If it would not, and if this upwards derivation were feasible, we would have failed to separate off consciousness as something different from biology in a relevant way.

One sign that there might be an obstacle to such an upwards derivation is that descriptions of states of phenomenal consciousness are readily appreciated by us, but they might not mean anything to, for example, Martians, whereas human biology would be perfectly meaningful to Martians.

Another sign is that we do not yet have much idea of what such an upwards derivation would look like, whereas we have a pretty good conception of upwards derivations of chemistry, and of biology, from physics. But it would be unwise to assume that this is how things will rest. Our knowledge of the brain has advanced enormously over the last 20 years. We do not know how much we will learn in the next 20 years.

Finally, we must consider the objection that if we did see how facts about states of phenomenal consciousness were to be derived, the descriptions of the derived objects would not look like descriptions of states of phenomenal consciousness. They would be descriptions of brain states. The descriptions would not glow with the feelings that we have, when our brains are in those states. But it is only Martians who definitely could not see the descriptions as glowing with those feelings. If we were to follow a Churchland-type programme of reform of our manner of speaking, so that we started to speak in terms of brain states, and if we associated descriptions of brain states with inner feelings, the descriptions might well come to glow with the corresponding feelings, even when we read them in neurology textbooks.

Tuesday 7 May 2013

Wings of Desire

Every so often in the film Wings of Desire (alternatively entitled Der Himmel über Berlin), directed by Wim Wenders and released in 1987, we hear extracts from the Lied vom Kindsein, by Peter Handke. The text is here:

and an English translation is here:

Plenty of lines in the Lied illustrate the claim that philosophy begins in wonder (Plato, Theaetetus 155d; Aristotle, Metaphysics 982b11-13): for example, "Warum bin ich ich und warum nicht du?"; and "Wann begann die Zeit und wo endet der Raum?".

It would be an interesting exercise to answer all of the questions that the Lied poses, and an equally interesting one to make all the connections that could be made between the text of the Lied and contemporary philosophy. For example, "Wie kann es sein, daß ich, der ich bin, bevor ich wurde, nicht war, und daß einmal ich, der ich bin, nicht mehr der ich bin, sein werde?", invites us to think about the conditions under which indexical and non-indexical terms can refer, and about the peculiar effects of using non-indexical terms to refer to oneself (with echoes both of Moore's Paradox and of Perry's essential indexical), as well as inviting us to think about coming to be and ceasing to be.

I shall here take a look at these words: "Ist das Leben unter der Sonne nicht bloß ein Traum? Ist was ich sehe und höre und rieche nicht bloß der Schein einer Welt vor der Welt?".

They have a particular relevance in the context of the film, in which angels see the world and the people in it only in black and white, and they cannot intervene causally to change people's lives, but on the other hand, they can listen to people's thoughts. But let us allow ourselves to go beyond that context, and ask what connection there may be between the idea that life is merely a dream, and the idea that we may perceive only an appearance, rather than the world.

I shall take the former idea to be that life is but a fleeting set of impressions, which if properly understood, could not be taken to be of any importance. The sentiment here is Pindar's, that a person is but a dream of a shadow (skias onar: Pythian Ode 8, line 95), ignoring the comfort that the following two lines give, with their reference to the effects of Zeus's favour. If we take the idea that life is a dream to concern importance, that idea is kept securely, and interestingly, separate from the idea that we do not perceive the real world. If we took the former idea to concern the process that produced our perceptions, then there would be a risk that the two ideas could come together, especially if it were possible to have dreams that were reliably veridical, for example by virtue of a mechanism of pre-established harmony, or by virtue of some unknowable that produced both the real world and our perceptions in parallel.

I shall take the latter idea to be that we perceive an appearance of a world, where that perceived world is distinct from the real world, and stands between us and the real world. The presence of the additional world, required by the text ("der Schein einer Welt vor der Welt", not "der Schein der Welt vor der Welt"), might be thought to steer us towards the sort of picture that would be given by a two-world interpretation of Kant, but we must allow for two non-Kantian elements. The first is that there is no requirement to regard the perceived world as empirically real. The second is the possibility (but not the certainty) that the perceived world is straightforwardly caused by the real world. The talk of our perceiving an appearance of the additional world also gives scope to introduce sense-data, or some such intermediary, but that is not the main point. The essential thing is the additional world.

First, suppose that life was a dream, in the sense of unimportance that I have just given. Could it be that we would nonetheless perceive the real world, and do so accurately - or, alternatively, perceive an intermediate world that was like the real world in its details, so that we at least had an accurate representation of the real world, and arguably did (indirectly) perceive the real world?

We could, so long as we could not act in the real world. That is, we would need to be in the impotent position of the angels in Wings of Desire, or of the deceased in Sartre's Les jeux sont faits. That would be both necessary and sufficient to make our perceptions of no importance, even though what was perceived or at least represented to us, the real world, was of importance, and even though the perceptions of people who could act in the real world, perceptions that might be qualitatively identical to our own, would be important.

If we could act to change the real world, perceptions that conveyed the state of the real world would matter, no matter how convoluted the process by which they conveyed that state. Perceptions of a world that was not the real world, and that did not convey the state of the real world, would not matter. They would be like the dreams that we, real agents in the world, in fact have when we sleep. Those actual dreams do not matter, except perhaps in indirect ways that do not rely on the accuracy with which they represent the real world.

Now suppose that life was not a dream, in the sense that our perceptions did matter. Would that impose any restrictions on the perceptual process?

We would need to be able to act in the real world, in order for our perceptions to be important. But our perceptions would also need to be useful guides to action. They would not need to give us wholly accurate information about the real world, but they would need to be such that paying attention to them led to action that was, on the whole, more appropriate than our actions would be if we did not pay attention to them. They could, however, fulfil that condition, whether we perceived the real world or some other, intermediate, world.