Hilary Putnam - REPRESENTATION AND REALITY.pdf - Putnam - MKTK

Preface

This book is primarily a criticism of currently fashionable philosoph -

ical views held in and around the cognitive science community . They

are the views of philosophers , including some of my former selves ,

but they are ' by no means held only by philosophers . I am dissatisfied

with these views , and so this book consists of philosophical criticism ,

but I am by no means depressed by what some will regard as the

" negative " outcome of my investigations . As I suggest in the last

chapter , it is only by seeing that the currently fashionable views do

not work that we can begin to seewhat the tasks of philosophy might

really be.

I was enabled to start work on what became this book by the gen -

erosi "ty of the National Endowment for the Humanities , which gave

me a fellowship in 1982 - 1983. I was able to tryout various versions

of the book in different lecture series that I was invited to give . One

of the earliest versions was tried out in Princeton , where I was briefly

a Visiting Senior Fellow in the Humanities ( in 1985 ) and had valuable

oppnrh1nitip ~ to discuss my criticism of functionalism with Gil Harman

, Saul Kripke , and David Lewis , among others. Later I tried out

other versions at Tel Aviv University and at the University of Munich ,

where I received many valuable comments and criticisms . The final

version of three chapters ( chapters 1 , 5 , and 7) formed the substance

of my Whidden Lectures at McMaster University in the fall of 1987 .

All of my colleagues have in one way or another contributed to my

thinking on this topic ( and none can be held responsible for the results

) . In particular , Burton Dreben persuaded me to undertake a radical

reworking of the penultimate version . An earlier version was

substantially rewritten as the result of criticisms by two close readers:

Charles Travis and my dearest critic Ruth Anna Putnam . And I owe

many thanks to the participants in my 1986NEH Summer Seminar.

Introduction

Many years ago I was invited to give a lecture on what is today called

" computer science " at a large eastern university . I titled my lecture

" Turing Machines ," because the most famous abstract model of a

computer is the model produced by Alan Turing . Today biographies

of Turing are reviewed in the New YorkTime , but in those early days

of the computer Turing was virtually unheard of . Thus it wasn ' t surprising

that someone at the university " corrected " what he assumed

to be my typo graphical error , with the result that posters announcing

that I would give a lecture on TOURING MACHINES went up all

over the campus . ( A few people left rather early in the lecture . )

My interest in computers and the mind thus dates from a very early

period . I may have been the first philosopher to advance the thesis

that the computer is the right model for the mind . I gave my form of

this doctrine the name " functionalism ," and under this name it has

become the dominant view - some say the orthodoxy - in contemporary

philosophy of mind .

In this book I shall be arguing that the computer analogy, call it the

" computational view of the mind ," or " functionalism ," or what you

will , does not after all answer the question we philosophers ( along

with many cognitive scientists ) want to answer , the question " What

is the nature of mental states? " I am , thus , as I have done on more

than one occasion , criticizing a view I myself earlier advanced.

Strangely enough , there are philosophers who criticize me for doing

this . The fact that I change my mind in philosophy has been viewed

as a character defect. When I am lighthearted , I retort that it might

be that I change my mind so often becauseI make mistakes , and that

other philosophers don ' t change their minds because they simply

never make mistakes. But I should like now, for once , to say something

serious about this . I have never forgotten the conversations I

had with Rudolf Carnap in the years 1953 - 1955 , and in particular , I

have never forgotten how Carnap - a great philosopher who had an

aura of integrity and seriousness which was almost overwhelming -

would stress that he had changed his mind on philosophical issues ,

xii Inuoduction

a sentence construction that was ever on Camap ' s lips . And , of

course , Russell , who influenced Catnap as Camap influenced me ,

was also criticized for changing his mind . Although I do not now

agree with Catnap ' s doctrines of any particular period , for me Camap

is still the outstanding example of a human

search for truth higher than personal vanity . A philosopher ' s job is

not to produce a view X and then , if possible , to become universally

known as " Mr . View X " or " Ms . View X. " If philosophical investigations

( a phrase made famous by another philosopher who " changed

his mind " ) contribute to the thousands- of - years - old dialogue which

is philosophy, if they deepen our understanding of the riddles we

being who

puts the

refer to as " philosophical problems , " then the philosopher who conducts

those investigations is doing the job right . Philosophy is not a

subject that eventuates in final solutions , and the discovery that the

latest view - no matter if one produced it oneself - still does not clear

away the mystery is characteristic of the work , when the work is well

done . I could add that what I just described as " changing my mind "

is not a matter of " conversion " from one view to another ; it is rather

a matter of being tom between opposing views of the nature of phi -

losophy itself . When I was a " scientific realist , " I felt deeply troubled

by the difficulties with scientific realism ; having given up scientific

realism , I am still tremendously aware of what is appealing about the

scientific realist conception of philosophy . I hope that the present

book at least partly reveals this " being tom . "

But enough of this . The computational view was itself a reaction

against the idea that our matter is more important than our function ,

that our what is more important than our how. My " functionalism "

insisted that , in principle , a machine (say, one of Isaac Asimov' S robots

) , a human being , a creature with a silicon chemistry, and a disembodied

spirit could all work much the same way when described

at the relevant level of abstraction , and that it is just wrong to think

that the essenceof our minds is our " hardware . " This much - and it

was central to my former view - I shall not be giving up in this book ,

and indeed it still seems to me to be as true and as important as it

ever did . What I shall try to do is the trick attributed to adepts in

jujitsu of turning an opponent 's strength against himself : I shall try

to show that the arguments for the computational view, in fact , the

very arguments I formerly used to show that a simpleminded identification

of mental states with physical - chemical states cannot be

right , can be generalized and extended to show that astraight -

forward identification of mental stateswith functional states , i .e. , with

computationally

characterized states , also cannot be right . Function -

and changed it more than once . " I used to think . . . I now think " was

Inb' oduction xiii

alism argued that mental states cannot simply be physical - chemical

states , although they are emergent from and supervenient on physical

- chemical states ; I shall now argue that mental states also cannot

be computational states , or computational cum physical states ( states

defined using a mixed vocabulary referring both to physical and to

computationalparameters ) , although they are emergent from and

may be supervenient upon our computational states. Unlike my Reason

, Truth and History, this book does not suggest a general stance

toward metaphysical questions , and , apart from a brief sketch in the

final chapter , I shall try to keep my own " positive " views out of the

work . Although there are many parts to the argument I will be presenting

, it was developed as a single argument . In the future I hope

to return to larger metaphysical questions ; here I aim at giving a fairly

complete account of one particular line of thought on one particular

philosophical issue , digressing ( as I shall have to ) into issues in the

philosophy of language , the theory of causation , the nature of truth ,

and so on , only to the extent that those issues bear on the chosen

topic .

The first three chapters actually grew out of two earlier papers . 1

Those papers were , in part , polemics against the views of my good

friend and former student Jerry Fodor. Fodor , I hasten to say, is not

the main target of this book ; but I have retained some of my polemic

against what I call " MIT mentalism ," because the arguments are

the present book doesn ' t have a " main target " ; for its aim is not so

much to refute one particular view as to establish the need for a different

way of looking at problems about " mental states. " At any rate ,

the intended contribution of these three chapters to that end is to do

two things : ( 1 ) to establish a close connection ( discovered and emphasized

throughout his career by w. ~ Quine ) between problems

about meaning and problems about belief fixation , by showing that

the holistic character of belief fixation in science bears deeply on the

issue of the individuation of " meanings " ( or " contents " or " intentions

, " as they are called by various philosophers ) ; and ( 2 ) to argue

that , in fact , thinking of " meanings " ( or " contents " ) as " theoretical

entities " - as scientific objects , objects which can be isolated and

which can play an explanatory role in a scientific theory - is a mistake

. In the course 9fthe argument I defend the view that there is no

criterion for sameness of meaning except actual interpretative practice

- a view made famous by Quine and Davidson .

Chapter 4 was difficult to place , because it is really on a " parallel

drawn on in later chapters . The main target of the '

present book is

one H . Putnam ( one of my former selves ) and those who have

adopted his views . Or perhaps it would be more accurate to say that

xiv Introduction

seriously as an explanatory theory, the " eliminationist "

philosophers ( e. g . , Quine ) are prepared to dismiss it as " secondclass

" talk , useful , perhaps , when we are doing " personal biography

" but having no place in the description of Nature ( which alone

has metaphysical import , according to these philosophers ) .

The best response to such an argument is to point out that the

difficulties with functionalist views ( developed in chapters 5 and 6 )

apply as much to " physicalist " accounts of reference as to " physicalist

" accounts of meaning . Reference is the main tool used in formal

theories of truth . But truth is not just a notion of folk psychology ; it ~

is the central notion of logic . None of these philosophers wishes to

give up logic . Eliminationist philosophers must meet this challenge -

the challenge of showing that their " let's eliminatetalk of the mental

from our metaphysical picture " stance doesn ' t require the " elimination

" of the notion of truth . Generally they try to do this

( a ) by saying that Tarski showed that the notion of " truth " can be

defined without

appealing to any dubious mentalistic or

" intentional

notions ; or ( b ) by claiming

that truth is just

a device for

" disquotation . "

If I did not respond to these views , then , I knew, my ' entire book

would evoke a " We told you so " from the eliminationists . Hence the

need for a chapter devoted to questions about truth . If I am right , the

idea that there can be an account of truth which has " nothing to do

with the mental " is an illusion .

Chapters 5 and 6 build on the previous material , especially on the

arguments for meaning holism . The purpose of these chapters is to

argue that mental states are not only Corn

position ally plastic ( the

same " mental state " can , in principle , be a property of systems which

are not of the same physical constitution ) but computationallyplastic

as well - the same mental state ( e. g . , the same belief or desire ) can in

principle be a property of systems which are not of the same com -

putational structure . Mental states cannot literally be " programs ," because

physically possible systems may be in the same mental state

while having unlike " programs ."

This leads to the difficult

kind of " equivalence " between the structures of all physic a Jly possible

systems ( organisms cum environments ) which contain a physically

possible organism who entertains a particular belief ; a kind of

question whether there is nevertheless a

track " to the rest of the volume ; yet I found it impossible to omit . One

influential line of thought in recent years maintains that what the

dif11cultieswith individuating ( / giving a scientific account of ) either

propositional attitudes or " meanings " show is that talk of both belongs

to " folk psychology . " While some philosophers take folk psychology

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