Physical David Papineau Interviewed by Richard Marshall

7/27/2019 Physical David Papineau Interviewed by Richard Marshall

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physicalDavid Papineau interviewed by Richard Marshall.

[Photo; Steve Pyke]

David Papineau is still roving in the deep philosophical waters even

though he knows that hell never know everything. He keeps writing hard

core books about his philosophical thoughts covering things such as

physicalism and how come everyone isnt a physicalist, substance and

property dualism and Kripkes worry that the mind brain identity is just

contingent. He wonders why philosophers think theres something wrong

with just knowing the facts. He thinks about the nature of colour

experiences, representation, and avoids mixing up methodological issues

with metaphysical ones. He thinks about the significance of Schrodingers


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cat,about whether there are any special laws that are not reducible to

physics and about the usefulness of historical kinds. This is a deep water

big beast from the philosophical depths: bangin.

3:AM: What made you become a philosopher? Has it been worth it?

David Papineau: My first degree was in mathematics. That was great, but

it didnt help with many of the things that puzzled me. I became a

philosopher because I wanted to understand everything, especially those

things that didnt make sense. And that has continued to be my

philosophical motivation. Thats one reason I have such a roving

philosophical eye once I have figured out a philosophical topic to my

satisfaction, I find myself moving on to new problems.

Has it been worth it? Absolutely. (I now realize that I wont have quite

enough time to understand everythingbut that hasnt stopped me

wanting to understand as much as I can.)

3:AM: You are an ontological naturalist. You think that modern science

makes some species of physicalism an irresistible position dont you?

Can you explain what your arguments are?

DP: Its simple enough. Nearly everybody nowadays accepts the causal

completeness of physicsevery physical event (or at least its probability)

has a full physical cause. This leaves no room for non-physical things to

make a causal difference to physical effects. But it would be absurd to

deny that thoughts and feelings (and population movements and

economic depressions . . .) cause physical effects. So they must be

physical things.

Note how this argument only bites for those things that do have physical

effects. If numbers say, or moral properties, have no physical effects, then

this argument gives us no immediate reason to say that they too must be

physical.

You might want to askif there is such a simple argument for physicalism,

how come everybody hasnt always been a physicalist? Thats a good

question, and there is a good answer. The causal completeness of

physics wasnt widely accepted until recently. A century ago mainstream


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science was still quite happy to countenance vital and mental powers

which had a downwards causal influence on the physical realm in a

straightforwardly interactionist way. It was only in the middle of the last

century that science finally concluded that there are no such non-physical

forces. At which point a whole pile of smart philosophers (Feigl, Smart,

Putnam, Davidson, Lewis) quickly pointed out that mental, biological and

social phenomena must themselves be physical, in order to produce the

physical effects that they do.

3:AM: This is not an eliminativist position regarding the mind but is

reductionist isnt it?

DP: Yesat least in the sense in which reductionist simply means

neither eliminativist nor dualism. Philosophers sometimes also use

reductionist more strictly, to mean type-identities between mental and


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physical categories, and to exclude non-reductive physicalisms like

metaphysical functionalism. Im not so sure that I am a reductionist in the

strict type-identity sense. The issues here are messy. But I certainly a

reductionist in the more general sense which is opposed to eliminativism

and dualism.

3:AM: Substance dualism is a target of this approach isnt it?

DP: Yes. But so is property dualism.

3:AM:Tim Crane, for example, might happily concede the arguments

about substance dualism but not concede that this means no species of

dualism cant be sustained. How do you respond to that sort of challenge?

DP: Well, the causal argument I gave above doesnt just imply that there

cant be a non-physical mental substance, but also that there can t be

non-physical mental properties. (Tim is always a bit cagey about exactly

what he thinks at this particular point. Im having dinner with him on

Saturday and will press him about it.)

3:AM: Kripke has anti-materialist arguments at the end of his Naming

and Necessityand you think hes wondering how mind brain identity

seems false even to people like yourself doesnt he? How do you handle

his challenge?

DP: Kripke says that physicalists like me cant explain the apparent

contingency of mind-brain identities. He maintains that, if I really believed

that pains are C-fibres, then I ought no longer to have any room for the

thought that they might come apart. His argument is that, since pains

arent identified via some contingent description, but in terms of how they

feel, I have no good way of constructing a possible world, so to speak,

where C-fibres are present yet pains absent.

(For the experts, note that Im here reading Kripke quite differently from

the widespread two-dimensionalist reading which takes him to be saying

that the problem for physicalists is simply that mind-brain identities are a

posteriori. This seems to me an absurd misreading of Kripke.)

My response to Kripke is simply to point out that mind-brain identity claims


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are very counter-intuitive. They continue to seem incredible even to

committed physicalists like myself. And that is why I go on half-thinking at

an intuitive level that there is a possible world with C-fibres and no pains. I

simply havent fully freed myself from the dualist intuition that even in the

actual world pains involve something more than from C-fibres. So of

course I intuitively think that they might come apart in other possible

worlds, even if they contingently co-occur in the actual world. (If pains are

extra dualist states generated by brain states, courtesy of the contingent

laws of nature operating in this world, then it immediately follows that

those brain states could occur without the conscious states, in a world

with different laws of nature.)

In truth, as Kripke points out, a clear-headed physicalist shouldn t be

thinking any of these dualist thoughts. If pains are one and the same as C-

fibres firing, then there really isnt any possibility of having one without

the other. Once you properly appreciates physicalism, this dissociation

should cease to appear possibleC-fibres with pains should strike you as

no more possible than squares without rectangles.

From my perspective, then, Kripkes intuition of contingency isnt a

thought that physicalists are somehow required to continue respecting

even after they have embraced their physicalism. Rather it is simply amanifestation of the psychological difficulty of fully embracing physicalism

in the first place.

This is a very straightforward response to Kripke, one that cuts through

the huge literature on the explanatory gap and two-dimensional

semantics. This whole literature is motivated by the idea that there is

something deficient about our current theoretical understanding of the

mind-brain relation, and that therefore we need some different anddeeper perspective that will somehow render mind-brain identities

transparently true. I say that there is nothing deficient about our current

theoretical grasp of mind-brain identities. The problem is only that they are

counter-intuitive. This doesnt show that there is anything wrong with our

theoretical understanding, any more than the intuition that the Earth is at

rest shows that there must be something theoretically wrong with

Copernicanism, or the intuition that time is moving shows that there is

something theoretically wrong with the block universe B series view of


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change. (A hankering for transparent understanding, grasp of natures,

having things revealed as they are, and so on, seems to run through a lot

of current philosophical debate. I dont get it. Whats wrong with just

knowing the facts?)

Of course, there remains the question of why we should find mind-brain

identities so persistently counter-intuitive, if they are true. But this is a

simple psychological question, and there are a number of plausible

explanations. Indeed this is a topic that is quite extensively discussed

outside philosophy, by developmental psychologists and theorists of

religion among others, under the heading of intuitive dualism. It is rather

shocking that so few of the many philosophers working on the

explanatory gap are familiar with this empirical literature.

3:AM: While we are on conscious experience, you deny that we can


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really see a million colours. This is territory that Pete Mandik is also

looking into isnt it? You offer an alternative to the orthodox view, and then

argue that phenomenological scrutiny isnt going to help decide which is

right. So first could you set out the two views?

DP: Colour experience is a new topic for me. Im not sure how closely itrelates to my previous work.

The orthodox view of colour experience assumes that, when we see a

colour difference between two surfaces viewed side-by-side, this is

because we have different responses to each of the two surfaces viewed

singly. Since we can detect colour differences between something like ten

million different surfaces, this implies that we are capable of ten million

colour responses to surfaces viewed singly.

I dont think that we are capable of anything like this many possible colour

responses. Instead I argue that the perception of colour differences

between two surfaces viewed side-by-side is a gestalt phenomenon.

There is a brain mechanism that works to identify colour differences

directly, without first identifying the absolute colour of each surface. So on

my view there is no reason to suppose anything like ten million colour

responses to surface viewed singly.

I think my view is rather more radical than Pete Mandiks. Both of us want

to show that colour perception doesnt transcend what can be

conceptualized, but I dont think he goes so far as to deny that it doesn t

involve different responses to all the discriminable surfaces.

On the methodological issue, I think that would be hopeless to try to

adjudicate between my view and orthodoxy by appeal tophenomenological introspection. We need to know about brain

mechanisms.

3:AM: So why does phenomenological scrutiny not help? Does this relate

your enthusiasm for phenomenal concepts? Youve written about

Wittgensteins Private Language Argument and argued that phenomenal

concepts are inconsistent with Wittgenstein. So who winsWittgensteins

argument or phenomenal concepts? Or both?


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DP: The phenomenal concept issue is rather different, I think. Here the

question is whether there are concepts of experiences that are made

available to subjects solely in virtue of their having had those experiences

themselves. Is there a way of thinking about seeing something red, say,

that you get from having had those experiences, and so isn t available to a

blind person? Many contemporary philosophers would say yes, despite

the fact that such concepts seem to conflict with Wittgensteins private

language argument. I have written a paper arguing that phenomenal

concepts do indeed conflict with the private language argument, and that

this is bad for Wittgenstein.

Still, as I said, this issue about phenomenal concepts is different from your

previous question of whether we can decide the structure of colour

perception by phenomenological introspection. After all, in supporting

phenomenal concepts I am in a sense siding with introspection against the

more behaviourist Wittgensteinians. But even so I dont think that

introspection is powerful enough to resolve the specific issue about how

many colours you can see.

3:AM: So what approach do you recommend?

DP: As I said, I dont think that we can figure out what is going on inconscious colour perception just by phenomenological introspection. We

need to know about brain mechanisms as well. We need to figure out what

information is present in the mechanisms that constitute conscious colour

perception. If neuroscientific research shows that those mechanisms only

contain comparative information about colour differences, and have

thrown away more fine-grained information about the absolute colours of

single surfaces, then that would support my position, in a way that just

introspecting our colour experiences cant.

The use of neuroscientific data to help resolve phenomenological

questions is proving a common theme in much contemporary thinking

about the mind. How rich are the contents of visual perception? Does

vision only tell us about shapes and colours, or does it also represent

higher categories like lemon or umbrella? Again, when we view a scene

fleetingly, do we consciously see all the details even though we dont

retain them, or do we not see them in the first place? Neurological


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information is crucial to deciding these questions. After all, they are so

interesting precisely because unaided introspection cannot resolve them.

Rather we need to know what is going on in the brain activities that

constitute visual awareness.

Of course, without any appeal to introspective phenomenology at all, we

couldnt get started on this kind of analysis in the first place, since the

initial identification of the brain activities that constitute visual awareness

must depend on correlating brain processes with phenomenological

reports. But we can engage in a kind of useful bootstrapping here. First

we use uncontroversial aspects of introspective phenomenology to figure

out which brain activities are in general responsible for visual

phenomenology and other features of consciousness. And then we use

the neuroscience to tell us what information is present in those brain

activities, and so to decide the trickier questions about the structure of


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consciousness. We start and end with phenomenological data, but we

couldnt have completed our inferential journey without the detour through

brain science.

3:AM: Does this relate to your anti-conceptualism about psychological

representation? Dont you want to defend your views about psychologicalrepresentation as scientific reductions, rather than as results of conceptual

analysis?

DP: I think it helps to distinguish the local semantic question about the

specific representational contents of perceptionwhat things do

perceptual states represent?from the more general meta-semantic

question of the nature of representationwhat it is for psychological

states to have representational contents at all?

On the former question, I rather incline towards conceptualism, in line

with my view of colour perceptionI dont think that we can represent

objects and properties for which we have no concepts, not even in

perceptual experience. In this sense I differ from those who defend non-

conceptual content like Michael Tye and Chris Peacocke.

But this local semantic question isnt something that I have written about

much, apart from my recent interest in colour vision.

On the general meta-semantic question, by contrast, I have written a lot,

mostly under the heading of teleosemantics. And herethough this is an

entirely distinct issueI am very much inclined to be anti-conceptualist, in

the sense that I think that the philosophical task (as always) is to come up

with a synthetic theory that fits the empirical evidence, and not to analyse

our a priori concept of representation or anything like that.

3:AM: You also look forward to reducing causality to probabilities as part

of this same approach dont you? And an issue here is avoiding mixing

metaphysics with methodology. Can you explain this, and also why this is

not a methodology issue but a metaphysical one?

DP: A certain kind of methodologically-minded philosopher of science is

quick to read off metaphysical conclusions from features of scientific

practice. Chemists dont derive their laws from fundamental physics, so


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reductive physicalism must be false. Biologists refer to natural numbers in

some of their explanations, so numbers must exist. I think that this kind of

thing makes for bad philosophy. The relevant features of scientific practice

often have mundane explanations which dont point to any deep

metaphysical moral. (Thus it would simply be messy and pointless for the

chemists to essay physical reductions, or for the biologists to offer

number-free explanations. Its a weird kind of science-worship that views

these practical considerations as clues to the nature of reality.)

Recent work on causation is a case in point. The metaphysical question is

whether causal relations can be reduced to non-causal general

regularities in some Humean style (though the modern Humean will work

with probabilistic generalizations rather than deterministic ones). Now,

methodological philosophers working on causal inference in practical

areas of science (epidemiology, economics, agriculture, . . .) have

observed that in practice causes are never inferred from probabilistic

patterns alone. When scientists do infer new causal conclusions from

probabilistic information, it is always against a rich background of prior

causal assumptions. (No causes in, no causes out.) And many

philosophers of science then move quickly from this practical

methodological observation to the metaphysical conclusion that causation

must somehow transcend any Humean pattern of probabilistic

generalizations. But this is not a good inference. Even if causation is at

bottom constituted by patterns of probabilistic generalizations, there are

obvious practical reasons for using prior causal knowledge to help identify

new causes, rather than trying to work everything out from first principles

every time.

The funny thing is that recent methodological work on causation itself

opens the way to a successful metaphysical reduction of causes to

probabilistic generalizations. I am thinking of Bayesian Nets. The

Bayesian Nets literature shows that, for any arrangement of causes, there

is a possible set of probabilistic relationships that entails that

arrangement. (No causes in, no causes out is a practical precept, not a

principled constraint.) Dan Hausman has written a terrific bookCausal

Asymmetrybuilding a reductive account of causation on this basis, and

I have written a couple of articles in the same strain. But as far as I knowwe are the only two people who read the Bayesian Nets stuff in this way.


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The reason, I suspect, is that nearly everybody else who works on

Bayesian nets is a methodologist rather than a metaphysician, much more

interested in the way science proceeds than in the nature of reality. And so

they think that if scientific practice treats causes as irreducible, then thats

good enough for them. Still, as I said, it is a bad idea to run metaphysics

together with methodology in this way. Ive nothing against philosophers

who are interested in the practicalities of science per se. Its their

metaphysical aspirations that irk me.

3:AM: Why dont you want to get into the box with Schrodingers cat and

what is the significance of this thought experiment?

DP: Schrdingers cat has a 50% quantum chance of coming out of the

box alive and a 50% quantum chance of coming out dead. If you got in thebox with it, the same would apply to you. So you really don t want to do

that.

I favour an interpretation of quantum mechanics (the Everett

interpretation) according to which reality branches in any chancy quantum

situation. On this view, Schrdingers set-up will give rise to in two future

branches of reality, one with a live cat, and one with a dead catand the

talk of 50% chances just indicates that the two branches are both equallyreal futures of the cat that originally entered the box.

Now, some philosophers have tried to make trouble for this interpretation

by arguing that, if it were true, then you would have no reason not to get in

the box with the cat. For on the Everett interpretation you would be sure to

come out of the box alive. True thered also be a future in which you come

out dead. But whats so bad about that, given that you wont be there to

experience it, and that you survive happily in the only future that you willexperience?

This is a terrible argument (and not made any better by David Lewis

defending it at length in his last published papersee my David Lewis

and Schrdingers Cat.) There may be good objections to the Everett

interpretation, but this isnt one.

Everybody agrees that a future in which you are dead is a very bad thing,

and that it isnt made any better by your not being around to notice how


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bad it is.

Everettians will simply agree with this, and observe that it follows that it s a

bad idea to get in the box with the cat. Doing so will cause the universe to

contain a future where you are dead, alongside the one where you are

alive, rather than leaving it as a universe where you are alive in all futures.Since a future where you are dead is a very bad thing, you really don t

want to do that.

3:AM: It seems to many people thinking about such matters that many of

our complex cognitive capacities are innate, but that raises the issue

about how they could be? How could we have evolved an innate capacity

to recognize doorknobs, say, given that presumably when we were

evolving our minds we didnt have doorknobs?

DP: I dont have much use for the concept of innateness. The everyday


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concept incorporates a number of different notions that can come apart in

in many ways, and as a result encourages a range of dangerously

fallacious inferences.

Nor is it easy to tidy up the concept. I guess the best move is to try to

equate innate with not learned. But this really only works as a necessarycondition. It looks a bit dotty as a sufficient condition. (Is my newfound

ability to sing innate, just because it wasnt learned, but caused by that

bang on the head last week?)

Even if we go with the idea of innate as not learned, I doubt that anything

worth calling a cognitive capacity will come out as innate. This is because

it seems unlikely that evolution would ever bother to write the whole of any

cognitive capacity into the genes, so to speak, instead of allowinginformation from the environment to play at least some part in shaping it.

Of course our genes will make some capacities very much easier to learn

than others, and of course our genes themselves are not learned. But the

point remains that genes themselves are not cognitive capacities, and that

anything worth calling a cognitive capacity will depend to some degree on

learning and so not be innate.

Having said that, I do have quite a lot of sympathy for Fodors picture ofconcepts as information-free atomic entities which get locked onto their

referents causally, and to that extent they neednt involve anything much

in the way of learning. But even so it seems perverse to call them innate.

Here we see again the oddity of treating not learned as sufficient for

innate. Even if no learning to speak of was involved in locking my mental

term onto doorknobs, it is odd to say that therefore my possession of a

doorknob concept is innate, just as it is odd to say that my head-injury-

caused singing is innate.

3:AM: As a physicalist youll say that all laws are physical laws I guess.

But a non-physicalist will say that there are non-physical laws such as

laws in economics, or biology and psychology. Fodor writes about these

as special sciences. Do you think there can be special sciences?

DP: No, I think that there are non-physical laws all right: genuine (if not

strict) laws written in the language of biology, economics, and so on. But Idont regard that as a contentious issue. Even reductionists about


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chemistry will think that there are special chemical laws whose formulation

makes essential use of chemical terminology.

The contentious issue is whether there are any special laws that aren t

reducible to physics. Fodor says yes, but I have always thought that there

are issues here. It has always puzzled me, along with Jaegwon Kim andNed Block, that there should be genuine lawlike patterns at the special

level, if physicalism is true (as Fodor agrees) yet the special laws are

variably realized by different physical processes in different cases (as

Fodor insists). Why should we always get the same results in the same

circumstances, if what is going on at the physical level is so different in

each case?

In a number of papers I have explored the idea that natural selectionmight fill the gap. Sometimes selection processes can ensure that there is

always some mechanism to produce such-and-such an effect in such-and-

such circumstances, even though that mechanism will be different in

different cases. All territorial birds have some way of discouraging

conspecific invaders, but the mechanisms vary (songs, displays,

odours, . . .). Natural selection has ensured that each species achieves

the requisite effect somehow, but it doesnt care, so to speak, how the trick

is done.

I still think that this story works in some cases, especially in the case of

people learning skills and other social behaviours (individual learning is a

kind of selection process). But more recently I have become interested in

another possible source of variably realized special science laws. The

idea is inspired by Ruth Millikans notion of a historical kind. Millikan

observes that some categorieschemical compounds, clouds, stars

enter into a range of generalizations because their instances have acommon physical essence. These are eternal kinds. But other categories

enter into a range of generalizations because they are all copied from a

common source. These are historical kinds. For example, all the many

copies of the Bible have the same first word, the same second word, and

so on. Each individual version of the Nuer belief system contains the

same tenet about twins, about ancestral spirits, and so on.

I now think that many generalizations of interest in the special sciences


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to concrete reality.

Let me finish with more two recent books that I learnt much from.

Peter Godfrey-Smith. Darwinian Populations. This book focuses on

concepts that are generally taken for granted in philosophic thinking aboutnatural selection, such as organism, heredity and reproduction. By

challenging these notions Godfrey-Smith brings out what is and isnt

essential to natural selection and opens up a fascinating range of new

issues in the philosophy of biology.

Richard Holton. Wanting Willing Waiting. Holton distinguishes two

notions of weakness of willacting against your better judgement, and

failing to stick to your resolutionsand shows that they are quite different.The book explores the latter idea, and uses a wide range of empirical

studies to cast new light on such topics as will-power, temptation,

addiction and free will.

ABOUT THE INTERVIEWER

Richard Marshall is still biding his time.

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First published in 3:AM Magazine: Monday, April 8th, 2013.

Physical David Papineau Interviewed by Richard Marshall

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Transcript of Physical David Papineau Interviewed by Richard Marshall