Empiricism in the Philosophy of Mind?

An Interview with Ned Block

Av Jakob Elster og Øistein Schmidt Galaaen

Is it possible to explain why certain states of the nervous system should be accompanied by phenomenal consciousness? Can mental states be reductively identified with physical states? How, if at all, can neuroscientific results be brought to bear on philosophical controversies about the mind? When it comes to hotly debated questions like these, Ned Block (Prof. of philosophy and psychology, New York University) is one of the world’s leading philosophers. When he visited Oslo in November 2006 to give three lectures,[1] we asked him some primarily metaphilosophical questions about how he pictures philosophy and its relation to empirical sciences.

In his talks Block argued that questions about consciousness are partly empirical questions. We therefore wanted Block to elaborate on what he takes to be the best methodological approach to consciousness.
First, a general question about the whole field: you put a great emphasis on qualia in the debate, and there seems to be a certain divide between philosophers of mind who either do not think it is an important problem, or at least think that we can put it in parenthesis and deal with many issues without looking at qualia for the moment, and those who think it is a central issue. What do you think of the question of qualia? What place should it have in discussions of consciousness?

It is true that there is this divide between people who are very interested in the problem of qualia, and those who aren’t. I myself think that many people who say that the problem of qualia is uninteresting or who at least are not at all interested in it themselves, really have philosophical views that are like Dennett’s: they think that qualia don’t exist. So I think that the disagreement over the centrality of the question is a philosophical position about the answer, one I disagree with. It is a mysterious thing why people have such different intuitions ? about, for example, the inverted spectra.[2] I routinely find when I teach classes of undergraduates, that some people say: – oh, yes, the inverted spectrum, I thought of that possibility when I was a kid. My own daughter, when I first explained the inverted spectrum thought experiment when she was seven, said: – oh, that explains why some people think that colours other than purple are the best colours. Whereas other people in effect say: ? I don’t know what you are talking about. So I expect that it has something to do with psychological differences between people, maybe to do with differences in ability to imagine things of certain sorts.

Since relatively a priori discussions of thought experiments like the inverted spectrum thought experiment are so widespread in philosophy in general and philosophy of consciousness in particular, we asked Block to elaborate a bit on the role of thought experiments in philosophy:

Some thought experiments are directed against a priori views, so if you can produce a counterexample to some a priori view, then all that is relevant is whether the counterexample itself is conceptually possible. So for example a priori functionalism can, I think, be refuted by thought experiments. But as far as establishing a positive thesis in philosophy, I don’t think mere thought experiments do you much good. For example, the inverted spectrum thought experiment, as I’m using it, is an imagined case. And then there is an argument about whether it is really possible, or actual. So I take the empirical argument that people’s spectra are really shifted with respect to one another to be part of an empirical argument that something that has the force of an inverted spectrum is really possible. Mere conceivability isn’t going to get you much. The transition between conceivability and possibility is of course philosophically crucial.

So while many philosophers seem to address questions about qualia primarily with the aid of thought experiments, others, including you, supplement thought experiments with a more empirical approach. But perhaps some of the former philosophers will say that in solving the hard problem of consciousness,[3] empirical data are more or less irrelevant because the problem can be described relatively a priori. And adding data it’s just like adding nines to 0.99 and never getting to 1. How do you respond to that?

The core of the hard problem is that nobody can think of an explanation of why the neural basis of a given sensation is the neural basis of that sensation rather than another one. But to argue from that fact, to the explanatory gap being a fundamental feature of our sensation, is to argue from poverty of imagination. The fact that nobody can think of it now doesn’t mean that nobody can be able to think of it later. What possibilities people can think of has a lot to do with what concepts they have and that has to do with what theories they have.

So you think the appropriate attitude towards the hard problem is “wait and see”?

Waiting won’t get us anywhere. We can look at the science to see if we see relevance to the hard problem. And we can also get clearer about the concept of consciousness itself. Understanding how it is possible for consciousness to be a brain process requires understanding how our concept of consciousness and our neural concepts can pick out the same thing. Resolving the concept of consciousness into component concepts that are more amenable to reduction is also important. And adjustment of the concept of consciousness may require attention to the neuroscientific advances.

Given what you have said so far, I guess the answer to this question of qualia probably gives itself, but I would still like to ask: What do you think of the sort of exotic solutions that have been proposed to this problem, like the revival of panpsychism[4]?

I don’t think it has much plausibility. I think that people are flailing around in the dark. I think that a much more promising way of proceeding, a way which I have proceeded myself, is to look at mainstream neuroscience. I think that if there is going to be a solution, it is going to come from there.

To the extent that empirical evidence is relevant to philosophical problems this raises questions about how much philosophers of mind need to know about cognitive science and neuroscience. Another prominent philosopher of mind, Jaegwon Kim, contends, officially at least, that he is working at a level of abstraction that makes empirical evidence relatively irrelevant. While acknowledging that empirical sensitivity varies across philosophy of mind, Block, on the other hand, maintains that empirical considerations will to a certain extent always be relevant:

I think there are relatively empirical parts of the field and relatively less empirical parts of the field. I myself think that even the relatively less empirical parts of the field, of the sort that Jaegwon works on, are responsive to empirical considerations. And Jaegwon often brings them in: for example the fact of multiple realizability. If you want to think about what reductive physicalism is, you need to have some understanding of actual cases of reduction, and in one way or another appeal to those models. I work on some of the same topics as Jaegwon in which empirical considerations come in but as background. The relevance of the empirical in worthwhile philosophy of mind is in my view a matter of degree. I think that good philosophy of mind always has some empirical grounding.

Another central aspect of the mind-body problem is reductionism. Can intentional states be reduced to physical states? Can qualia? Quite generally the reductionism debate in philosophy of mind is often formulated in terms of identities: Mental properties or events must be identified with physical events or properties. Since reductionism is also an issue on which Block has published extensively, we asked him some questions about how he pictures reductionism.
Philosophers of science like Ken Schaffner and John Bickle sometimes complain that philosophers of mind are operating with antiquated models of reductionism, and suggest instead that we need to look to reductive projects in science to find out what actual reductionism might look like. Do you have any views on that?

I have read some old things of Schaffner’s where he points out that in real cases, theories in science are always found to be false when they are reduced. I think that point is well taken, but still I think there is a kind of idealized model where you ignore those false aspects. So I’m not sure that that aspect of the true facts about real reductions plays an important role in some of the debates that I’m interested in.

As suggested by e.g. the Churchlands, there might then be a spectrum of possible reductions ranging from eliminativism via partly reformative reductions to perfectly conservative identities. What kind of reduction, if any, do you think is more likely to occur in the case of folk psychology – eliminativism, identities or something in between?

It would be very surprising if every bit of common sense thinking about the mind were true. I think most aspects of folk psychology are very likely to be vindicated, but not all, I imagine. So I have some agreement with the Churchlands on that. I think that the model where some parts of folk psychology are given up is undoubtedly going to be right. Neuroscience will vindicate that there are beliefs and desires, and will tell us what they are in neural terms, but they will also tell us that they don’t have all the properties that we formerly thought they had. So that is where I disagree with people like the Churchlands. The Churchlands are too quick to see elimination. Paul Churchland has long argued that beliefs and desires require language-like representations; those representations don’t exist, so there are no beliefs and desires. But beliefs and desires don’t require language-like representations. If you come up with an argument based on very early work to the effect that the dog never wants to go out, you should think again ? or be guilty of serious hubris. Look, you can think that there is going to be some mismatch between science and common sense without thinking that the entities or types that are postulated by folk psychology turn out not to correspond well enough with anything in reality.

There is a lot of talk about identities in the reductionism debate. And Kim makes some fairly strong claims: you need identities to get reduction, and you get identities if and only if the relevant properties are functionalizable. So he sets aside a lot of reductionist models, including your model and models from science.

Yes, and I disagree with that. My disagreement is on a par with standard philosophical disagreements. What he calls functionalizability is a priori definability in functional terms as a definite description of the thing we call such and such a role. And I think we rarely have such definitions – maybe never. So we differ on that aspect of reduction. I agree with many things that Kim says, but not that model of reduction and the source of the disagreement is disagreement about what we know a priori.

Reductionism brings us to a question about physicalism in general. Kim says that he wants to define the physical very widely as encompassing the biological domain. Nevertheless, it seems that much of the debate is conducted at the level of physics. But neuroscience would seem more relevant to questions about the mind than physics properly speaking?

Jaegwon would agree, which is why he includes biology in physics. I think neuroscience is especially relevant to perception and issues about phenomenology and qualia. I think that psychology is much more relevant to propositional attitudes. Both are relevant to emotions; physics of the kind in physics textbooks is not very relevant to any of these issues.

Because there are of course attempts to relate consciousness to quantum mechanics?

There is an excellent paper by Rick Grush and Pat Churchland, showing that the magnitude of quantum mechanical effects in the brain is not large enough to explain differences in behaviour.[5]

You suggest that biology will be the paradigmatic science for understanding consciousness in the 21st century, and I guess that at least some philosophers of biology would say that the entities described within biology can only be functionally described. So that if you reduce something to biological entities, at least you would need, in order to define them, to functionally describe these entities. Could you do that and still say that you are not involved in functionalism?

Yes. You know I have a paper on the web with an answer to this objection.[6] It’s a paper that is in a Festschrift for Jaegwon Kim, edited by David Sosa. My answer is that the difference between a view of the nature of properties in terms of role and in terms of realizers of the role is a distinction that operates at every scientific level. And we have reason to believe that it is significant even at the lowest level of physics.

Assuming that empirical evidence can and should be brought to bear on certain areas of philosophy of mind, it might nevertheless appear that some philosophers of neuroscience who do look at empirical evidence stand in danger of losing sight of the conceptual and foundational philosophical issues in which Block engages. Since Block has published a critical review of Patricia Churchland’s Brainwise,[7] we asked him to elaborate on his agreements and disagreements with her.
I read your review of Pat Churchland’s Brainwise, where you made some interesting remarks about philosophy of neuroscience. It seems to me that you can do philosophy of mind in a too a prioristic manner, but you can also go too far in the other direction by having relatively little patience with foundational issues. So could you elaborate a little bit on what you think is the right balance here?

Pat Churchland thinks that neuroscience can solve the age-old problems of philosophy, like the problem of free will. Her solution to the problem of the free will is plausible, but it is a fairly standard form of compatabilism with an account of what freedom is in terms that people who knew none of the science have also advocated. I think the action in philosophy of neuroscience is in conceptual issues that come up in the neuroscience itself. One example is Tyler Burge’s work on whether externalism is supported by work in visual perception. Another example: I am working on a paper about the issue of whether it is possible to disentangle consciousness from cognitive access to it, given that the data one gets is always contaminated by cognitive access.[8] When Churchland approaches such issues, she has the impatience displayed by some empirical scientists. She wants “just the facts”. She seems to think that there are no interesting philosophical issues except the old chestnuts. So that is where I think she goes wrong.

Empirical approaches now seem to be in vogue, not only in philosophy of mind, but more generally in areas like ethics or moral psychology. Given his arguments for the relevance of empirical methods in philosophy of mind, we asked Block whether he thought an empirical approach is the appropriate methodology for philosophical questions in general or whether certain fields are more amenable to empirical approaches than others:

Some are more amenable than others. I think philosophy of mind is particularly amenable, and there are certain issues in metaphysics that don’t seem at all amenable to it. But I think an empirical background is always being presupposed in almost any philosophical inquiry. You know, Rawls pointed out that in the original position the agents are to be equipped with basic facts about human nature. So he thought, and I think rightly, that the correct theories in ethics cannot abstract away from basic facts about human nature. It is always a case of more or less. Few interesting parts of philosophy are absolutely, completely non-empirical. I’m not much of a fan of conceptual analysis or a priori truth. If there are a priori truths they are not very useful in philosophy.

Notes

1. The manuscripts on which two of these lectures – ‘The Methodological Puzzle of the Neural Basis of Phenomenal Consciousness’ and ‘Wittgenstein and Qualia’ – were based an be downloaded here: http://www.hf.uio.no/ifikk/forskning/forskningsprosjekter/csmn/activities/NedBlock.html.
2. ‘Inverted spectra’ refers to a series of thought experiments where one envisions that color-experience is systematically shifted in various ways across individuals. The alleged possibility of such scenarios has been used e.g. to argue against positions like physicalism, functionalism and behaviorism.
3. That is, roughly, the problem of explaining why a given neural state should be accompanied by one conscious experience rather than another, or why it should be accompanied by any conscious experience at all.
4. That is, the view that not only biological organisms, but also other physical objects like stones have consciousness.
5. Block is probably referring to: Grush, R. and Churchland, P.S. (1995) Gaps in Penrose’s toilings. Journal of Consciousness Studies, 2(1), 10-29
6. “Functional Reduction”: http://www.nyu.edu/gsas/dept/philo/faculty/block/papers/Kimfestschrift.pdf
7. “Neurophilosophy or philoneuroscience” Science 301, 2003, p. 1328. Available here: http://www.nyu.edu/gsas/dept/philo/faculty/block/papers/BrainWise1.pdf
8. Available here: http://www.nyu.edu/gsas/dept/philo/faculty/block/papers/puzzle.pdf