Beyond Reduction
PHILOSOPHY OF MIND
SERIES EDITOR
David J. Chalmers, Australian National University
Self Expressions
Minds, Morals, and the Meaning of Life
O
WEN FLANAGAN
The Conscious Mind
In Search of a Fundamental Theory
D
AVID J. CHALMERS
Deconstructing the Mind
S
TEPHEN P. STICH
The Human Animal
Personal Identity without Psychology
E
RIC OLSON
Minds and Bodies
Philosophers and Their Ideas
C
OLIN MCGINN
What’s Within?
Nativism Reconsidered
F
IONA COWIE
Dreaming Souls
Sleep, Dreams, and the Evolution of the
Conscious Mind

Gut Reactions
A Perceptual Theory of Emotion
J
ESSE J. PRINZ
Ignorance and Imagination
On the Epistemic Origin of the Problem of
Consciousness
D
ANIEL STOLJAR
Simulating Minds
The Philosophy, Psychology, and
Neuroscience of Mindreading
A
LVIN I. GOLDMAN
Phenomenal Concepts and Phenomenal
Knowledge
New Essays on Consciousness and
Physicalism
E
DITED BY TORIN ALTER AND SVEN WALTER
Beyond Reduction
Philosophy of Mind and Post-Reductionist
Philosophy of Science
steven horst
1
2007
3
Oxford University Press, Inc., publishes works that further
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Fo r my mo th e r
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Preface
It is difficult to fix a date for the beginnings of this book with any real
precision. It is one of several fruits of a project that began in the
summer of 1993. At that time, having finished all but editorial work
on Symbols, Computation and Intentionality (Horst 1996), I began to
explore a topic on which I had left a substantial promissory note in
that book: namely, the question of whether mental phenomena like
intentionality and phenomenology could be naturalized. It was with
this in mind that I attended NEH Summer Institutes on Naturalism
(at the University of Nebraska, hosted by Robert Audi) and Meaning
(at Rutgers University, hosted by Jerry Fodor and Ernie LePore). One
thing that became clear to everyone at Audi’s institute was that, while a
great number of philosophers wish to lay claim to the word ‘natural-
ism’, they in fact use that word in a surprising number of ways.
Chapter 1 of this book, which attempts to bring some order to this
motley assortment of usages, grew out of extended research into the
contemporary and historical usages of the term and the research
projects associated with it.
When I started out on the project, I still assumed, as I had in
Symbols, Computation and Intentionality, that intertheoretic reductions
were the rule in the natural sciences and that the explanatory gaps
encountered with respect to consciousness, intentionality, and norma-
tivity present unique problems. During a 1997–98 sabbatical at Prince-
ton and Stanford’s Center for the Study of Language and Information,
made possible by an NEH Fellowship and by sabbatical support from my
home institution, Wesleyan University, I had several conversations with
philosophers of science (Paul Humphreys, Bas van Fraassen, Patrick
Suppes, and my Wesleyan colleague Joseph Rouse) who regarded my

A slightly trimmer version was read by two anonymous referees, who con-
firmed my suspicions that this was really not a single book but several books,
with different topics, for different audiences, while also providing helpful (and
sympathetic) feedback on many of the main points.
The book you are now reading, while descended from those drafts of Mind
and the World of Nature, involved a complete rewriting of everything, with a
narrower orientation and greater focus upon reductive forms of naturalism. In
its final form, it is particularly indebted to suggestions from Thomas Polger of
the University of Cincinnati, who read the penultimate draft. Tom’s own book
(Polger 2003) defends a form of type-identity theory, on which account he
might seem to represent a point of view almost completely antithetical to my
own view, which is not only antireductionist but antinaturalist. However, he
and I actually agree on a number of points, ran ging from the failure of the
classic reductionist project of Carnap and Nagel in philosophy of science to the
need to adopt some form of pluralism in philosophy of science and philosophy
of mind. However, the forms our pluralisms take are quite different. Thanks
viii preface
also go to a number of people who kindly agreed to read chapters at various
stages along the way, particularly Michael Silberstein and Joe Rouse. The final
product is better for their input.
Neither memory nor space allows me to give due credit to all of the people
with whom I have had profitable conversations over the years that have helped
to shape the final form of this book. I shall single out a few, hopefully without
giving offense to those who have been omitted . Wesleyan University has
supported this work through two semester-long sabbaticals. David Chalmers,
now at the Australian National University, has been a continuing source of
lively engagement as our views have drifted apart over the past decade, and was
so kind as to include me in the NEH Summer Institute on Consciousness and
Intentionality he and David Hoy hosted at the University of California at Santa
Cruz in 1992. My Wesleyan colleague Joseph Rouse has been helpful on a

and incomprehensible gaffes are, of course, entirely of my own doing.
preface ix
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Contents
Introduction, 3
Part I Naturalism and Reduction in Philosophy of Mind
and Philosophy of Science
1. Varieties of Naturalism: What Is a Naturalistic Philosophy
of Mind? 11
2. Reduction and Supervenience: The Contemporary
Problematic in Philosophy of Mind, 23
3. The Demise of Reductionism in Philosophy of Science, 47
Part II Philosophy of Mind and Post-Reductionist
Philosophy of Science
4. Reductionism and Eliminativism Reconsidered, 67
5. The Explanatory Gap and Dualism Reconsidered, 83
6. Nonreductive Physicalism and Mysterianism, 93
Part III Cognitive Pluralism, Explanation, and Metaphysics
7. Two Forms of Pluralism, 121
8. The Scope and Pl ausibility of Cognitive Pluralist
Epistemology, 151
9. Cognitive Pluralism and Modal Metaphysics, 183
10. Cognitive Pluralism and Naturalism, 199
Notes, 205
Bibliography, 215
Index, 225
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Beyond Reduction
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Introduction

anomaly. The centrally important properties of the mind, such as consciousness,
intentionality, and normativity, do not seem to be reducible to what the brain
does, or indeed to any facts specifiable in the languages of the natural sciences.
This problem, variously known as the ‘‘explanatory gap’’ (Levine 1983) or
the ‘‘hard problem of consciousness’’ (Chalmers 1996), was posed almost four
centuries ago by Descartes and has regained a good deal of notoriety in recent
years. Is the appearance that there is such an explanatory gap merely a
symptom of the current immature state of the sciences of the mind? Or
perhaps of philosophers’ ignorance of recent work in those sciences? Or is it
a real and abiding feature of our understanding of the relationship between
ourselves and the world of nature? And if so, if there is a principled limit to our
ability to understand and explain the mind in terms of something else, what
does this entail? Does it imply some form of dualism? Or that our ways of
conceiving of the mind are so misguided that they do not in fact really refer to
any real phenomena at all? Or perhaps merely that there are limitations to our
own understanding that prevent us from having the same kind of insight into
the basis of our own thinking that we have into things like atoms and metabolic
processes? If we assume that intertheoretic reduction is the rule in the sciences
generally, the explanatory gap would seem to be a crucial philosophical linch-
pin upon which our understanding of our place in the universe turns.
My contention in this book is that this entire problematic is misguided and
is an artifact of an erroneous view in the philosophy of science. The crucial
error is to assume that intertheoretic reductions are in fact the norm in the
sciences (an error that was shared by proponents of the reductionist orthodoxy
in philosophy of mind and by its challengers responsible for the resurgence of
interest in the explanatory gap). This view was, to be sure, a central philosophi-
cal orthodoxy in the middle parts of the twentieth century. Yet over the past
several decades, it has been decisively rejected within philosophy of science
itself, and for reasons having nothing to do with the special problems encoun-
tered in examining the mind and its relationship to the brain. Biology is not

the sense of not being reducible to basic physics. My suggestion is that this is
best understood by considering the sciences as cognitive enterprises: enter-
prises of modeling local features of the world (and of ourselves) in particular
representational systems. Such models are local and piecemeal. They are also
idealized in a variety of ways that can present principled barriers to their
wholesale integration into something like a single axiomatic system. This
view might be seen, in one respect, as a kind of generalization of the ‘‘Myste-
rian’’ views offered by Colin McGinn and Stephen Pinker. Whereas McGinn
and Pinker suggest that the psychological explanatory gaps might be a conse-
quence of limitations of our cognitive faculties, I suggest that the gaps repre-
sented by failures of reducibility in the science of natures might be understood
in much the same fashion.
All of this might sound like a perfectly sensible move in the familiar
direction of nonreductive physicalism: everything might supervene upon basic
physics, and yet our minds may prove incapable of a global understanding of
these supervenience relations in the form of the kind of axiomatic reconstruc-
tion of the special sciences envisioned by Carnap or Nagel. However, I think
this would be the wrong conclusion to draw, for a number of reasons. First,
I contend that, once one has rejected reductions, one no longer has a basis for
preferring physicalism to its alternatives either. Second, the cognitivist turn
involved in Cognitive Pluralism has metaphysical implications of its own. We
can no longer rest content with a naı
¨
ve realism that assumes that the world
divides itself in a unique, canonical, and mind-independent way into objects
and properties. Rather, the ways we carve up the world are inextricably bound
up with the ways minds like ours represent features of the world. While
Cognitive Pluralism may leave the inventory of the world as conceived by the
sciences or by common sense essentially untouched, it cannot take that inven-
tory as ontological bedrock. Like Kantian Idealism and Pragmatism, it

profession and in the educated public, who think that reductionism is some-
how implied either by the current state of the sciences or by the best philoso-
phy of science available. I think that this assumption is widespread, but false.
Indeed, I regard reductionism as a doctrine both false and harmful. I am not
sure what I would do if I thought it harmful but true. Happily, I am not in that
position.
Overview of the Book
This book is divided into three parts. Part I sets out some background on the
problems and frames the terms of debate, hopefully in a way that will provide
both a useful systematization for fellow specialists and an accessible point of
entry for nonspecialists. Chapter 1 examines a variety of views that go by the
name of ‘‘naturalism’’ in philosophy of mind, and contrasts them with the use
of the word ‘naturalism’ in other areas, such as epistemology and philosophy of
science. I argue that naturalistic philosophy of mind involves two kinds of
claims: that mental phenomena can be explained in naturalistic terms, and that
mental phenomena are metaphysically supervenient upon and determined by the
6 beyond reduction
phenomena encountered in the natural sciences. I also argue that there is good
reason for the fact that specifically reductive forms of naturalism have enjoyed
pride of place in philosophical discussions, on the grounds that what I call
‘‘broadly reductive explanation,’’ and only that form of explanation, guarantees
metaphysical supervenience as well.
Chapter 2 undertakes a survey of the principal positions on the current
scene in philosophy of mind: reductive and nonreductive materialism, elim-
inativism, dualism, and Mysterianism. These are presented in terms of the
answers they give to four questions:
1. Can the phenomena of the (nonmental) special sciences be
reductively explained?
2. Do the phenomena of the (nonmental) special sciences supervene
upon the physical facts?

’s (1993) ‘‘promiscuous
pluralism,’’ a kind of realist pluralism with a radically expanded ontological
inventory. The second is the view I wish to recommend, Cognitive Pluralism.
introduction 7
Cognitive Pluralism is first discussed in chapter 7 in epistemological terms, as
a possible explanation of why there might be abiding explanatory pluralism in
the sciences. Chapter 8 then argues that the key notions developed in chapter 7
—especially that the mind understands the world through special-purpose,
idealized models—is not a feature distinctive of scientific understanding so
much as it is a general feature of human cognitive architecture, of which
scientific understanding is but a particularly exacting and regimented case.
In both of these chapters, it is argued that the use of special-purpose, idealized
models, each employing a representational system suited to its individual
problem domain, (a) may be a deep ‘‘design principle’’ of human cognitive
architecture that cannot be avoided, and (b) is sufficient to explain some types
of abiding disunities in our knowledge as artifacts of our cognitive architecture.
Cognitive Pluralism is then discussed as a metaphysical thesis in chapter 9.
There it is argued that both its cognitivist and its pluralist strands give us
reason to rethink the status of intuitions about claims for metaphysical neces-
sity and supervenience that have shaped recent discussions in the metaphysics
of mind. Chapter 10 returns to the topic of naturalism, and asks whether a
naturalist might also be a Cognitive Pluralist, and vice versa. The answer to this
depends upon the operative sense of the word ‘naturalism’. If it is used as it
is employed in philosophy of science and epistemology—that is, as signifying
a rejection of aprioristic theories in favor of theories more engaged with
the sciences themselves—then Cognitive Pluralism is intended as a paradigm
example of a ‘‘naturalistic’’ approach. But if it signifies the view that there
is a single privileged set of ‘‘natural’’ facts upon which all of the others
depend, and from which they may be derived, Cognitive Pluralism is a radical
repudiation of naturalism.

I am not really pointing out anything new here. The ambiguity
of the word ‘naturalism’ has been widely noted, and has been remarked
upon for perhaps half a century now. The midcentury philosopher of
science Ernest Nagel, in his 1955 presidential address to the American
Philosophical Association, noted that ‘‘the number of distinguishable
doctrines for which the word ‘naturalism’ has been a counter in
the history of thought is notorious’’ (3). In their introduction to the
anthology Naturalism: A Critical Appraisal, Wagner and Warner (1993, 3) express
a similar view:
Participants in current discussions of naturalism seem to assume that
the meaning of ‘naturalism’ (‘naturalist program’, etc.), its motivations
and—often—its correctness, one way or the other, are almost obvious.
The historical situation makes such assumptions exceedingly unlikely.
Philosophers have taken just about every possible stance with some
manner of justification, and all of the main programs within this area
(‘‘naturalism,’’ ‘‘phenomenology,’’ ‘‘analytic philosophy,’’ and so forth)
have been open to sharp differences of interpretation by their adherents.
In a similar vein, David Papineau (1993, 1) begins his book Philosophical Natu-
ralism with the words, ‘‘What is philosophical ‘naturalism’? The term is a
familiar one nowadays, but there is little consensus on its meaning. . I suspect
that the main reason for the terminological unclarity is that nearly everybody
nowadays wants to be a ‘naturalist’, but the aspirants to the term nevertheless
disagree widely on substantial questions of philosophical doctrine.’’ Some phi-
losophers, such as Jesse Hobbs (1993), have taken Papineau’s point that ‘‘nearly
everybody wants to be a ‘naturalist’ ’’ even further, raising the question of
whether the word ‘naturalism’ is simply ‘‘a contemporary shibboleth.’’ If one
came to this conclusion, one would, I think, be half right. The word ‘naturalism’
does tend to function as a kind of shibboleth—that is, as a word whose use
distinguishes ‘‘members of the tribe’’ from outsiders. And it is, I think, true that
naturalism has become a kind of ideology in philosophical circles; that is, it is