Topics in Cognitive Science 1 (2009) 216–230

Copyright  2009 Cognitive Science Society, Inc. All rights reserved.

ISSN: 1756-8757 print / 1756-8765 online
DOI: 10.1111/j.1756-8765.2009.01014.x

Introduction: Philosophy in and Philosophy of

Cognitive Science
Andrew Brook
Department of Philosophy and Institute of Cognitive Science, Carleton University

Abstract
Despite being there from the beginning, philosophical approaches have never had a settled place
in cognitive research and few cognitive researchers not trained in philosophy have a clear sense of
what its role has been or should be. We distinguish philosophy in cognitive research and philosophy
of cognitive research. Concerning philosophy in cognitive research, after exploring some standard
reactions to this work by nonphilosophers, we will pay particular attention to the methods that philos-
ophers use. Being neither experimental nor computational, they can leave others bewildered.
Thought experiments are the most striking example but not the only one. Concerning philosophy of
cognitive research, we will pay particular attention to its power to generate and test normative claims,
claims about what should and should not be done.

Keywords: Philosophy of cognitive science; Philosophy in cognitive science; Philosophical methods;

Thought experiments; Justifying norms

1. Introduction

One of the features of our new journal, topiCS, will be groups of papers on a single
theme running across a number of issues. One of the themes is the place of philosophy in
cognitive science. A number of cognitive researchers trained in philosophy who have made
signal contributions to cognitive science will launch the theme, Dan Dennett, Bill Bechtel,
Paul Thagard, Pierre Jacob, Tom Metzinger, and Zenon Pylyshyn.1 There will be opportuni-
ties for others to enter the conversation. In this introduction, I will try to specify the theme
in detail, say something about why it is interesting, introduce some of the ways in which
philosophically knowledgeable researchers contribute to cognitive research, and sketch
some of the methods they use. (Note: Not all cognitive researchers trained in philosophy

Correspondence should be sent to Andrew Brook, Department of Philosophy, Carleton University, Ottawa,
Ontario, Canada K15 5B6. E-mail: abrook@ccs.carleton.ca
 A. Brook ⁄ Topics in Cognitive Science 1 (2009) 217

work in Departments of Philosophy and not all philosophically knowledgeable researchers

have formal training in philosophy).
Philosophy has never settled into a stable position in cognitive science and few cognitive
researchers without training in philosophy have a clear sense of what it has contributed and
should contribute. Overall, it has never achieved the position of behavioral experiments,
computational modeling or system building and, more recently, cognitive neuroscience.
There have of course been a wide range of collaborations between individuals trained in phi-
losophy and individuals with other training. All the contributors launching our theme have
done extensive work with researchers from other backgrounds. Others include Patricia
Churchland, Jesse Prinz, Jerry Fodor, Ned Block, Martin Davies, Brian McLaughlin, Evan
Thompson, Aaron Sloman, Nancy Nersessian, Georges Rey, Peter Carruthers, Rob Stainton,
Kathleen Akins, Jeff Pelletier, Steven Stich, Michael Anderson, Rick Grush, et al.—a com-
plete list would be quite long. Concepts, color perception, explanation ⁄ creation of theory,
reference and assertion in language, and consciousness are some of the topics. Two bodies
of collaboration have even come to have names, the philosophy and neuroscience movement
(Brook & Akins, 2005) and experimental philosophy (the activity of testing philosophical
theses and philosophers’ intuitions empirically) (Appiah, 2008; Knobe & Nichols, 2008).
These achievements notwithstanding, the nature of philosophically inspired research and
its potential for interacting with other work to shed light on cognition is not well understood
and relatively few researchers with other backgrounds make use of philosophical work
in their research. Our aim in this theme is to explore what philosophy could and should
contribute to cognitive research.
The unsettled place of philosophy in cognitive science is not because philosophy is a cog-
nitive Johnny-come-lately. Philosophers have been a part of cognitive science since the
activity was merely a twinkle in the eyes of a small but hardy group of pioneers in the
1960s. Hilary Putnam and Jerry Fodor come immediately to mind. In the 1960s, those two
did much to articulate the view that came to be known as functionalism. Functionalism (as
the term is used in cognitive research) is the idea that cognitive processes are to be under-
stood by what they do, that is, how they function, rather than in terms of their structure or
constituting mechanisms. Even when mechanisms are invoked, they are usually expressed
as organized structures of subfunctions which, when put together, implement a more com-
plex cognitive function. Functionalism is something like the official philosophy of mind of
cognitive science and has been from the beginning. This important contribution notwith-
standing, work done using philosophical tools did not go on to build a stable, well-under-
stood role for itself in the new science.2
There is a tendency among those trained in philosophy to blame themselves for this
state of affairs. Well, not themselves—other philosophers. The kinds of philosophy most
relevant to cognitive science are philosophy of mind, language, and science (including
parts of epistemology). According to these critics, too many philosophers in these sub-
fields have been at best indifferent, at worst hostile, to science. Indeed, they often reach
conclusions without even knowing what science could tell them about the topic on
which they are pronouncing. There is doubtless some merit to these charges. To take a
personal example, I did a doctorate in philosophy at Oxford some decades ago. I have
218 A. Brook ⁄ Topics in Cognitive Science 1 (2009)

no recollection of ever setting foot in the experimental psychology building—even

though I was working on consciousness! However, our goal in this series of papers is,
in the words of the old Johnnie Mercer song, to e-lim-in-ate the negative and ac-cent-
u-ate the positive.3 Even philosophers who are well versed in the relevant science have
never had a settled role in cognitive science. When philosophers’ work on cognition
has had shortcomings, it is far easier to beat up on them for their shortcomings than to
identify and clearly articulate what work done using philosophical techniques could and
should contribute. The latter will be the primary focus of the papers in the theme to
which this paper is the introduction.
To make progress we need to distinguish philosophy in cognitive science and philoso-
phy of cognitive science. The former embraces work done on topics such as mind and
language that are also studied using other approaches such as behavioral experiments and
theoretical linguistics, so philosophy of mind and language. The latter is a branch of the
philosophy of science and is a meta-study. It studies what others do—rather than doing
cognitive science, it studies cognitive science. Both play an important role. The nature
and role of philosophy of cognitive science is clearer and better understood than the nat-
ure and role of philosophy in cognitive science. The first two papers in the current theme
(Dennett, this issue, pp. 231–236; Thagard, this issue, pp. 237–254) deal mainly with
philosophy in cognitive science so we will start with it, then turn to the role of philoso-
phy of cognitive science. The hope is that these discussions will provide a foundation for
the papers to come in this theme.

2. Philosophy in cognitive science

When philosophy plays a role in cognitive science, it is usually philosophy of mind, phi-
losophy of language. Logic has also played a role. We will focus on philosophy of mind and
language. Logic has certainly made a contribution via its role in formal linguistic theory and
some kinds of AI. And it gives rise to some interesting philosophical questions, for example,
whether patterns of valid inference reflect something deep about human cognition or merely
the requirements of an invented system of norms. However, logic has a stable place in the
research to which it contributes.
This is not true of philosophy of mind and language. The range of topics that phi-
losophers of mind and language tackle is as broad as cognitive science itself, going
all the way from formal semantics and pragmatics to memory, perception, reasoning,
emotion, and consciousness to how to make neuroscience more useful to cognitive
research, but most nonphilosophers have no clear sense of what or even whether phi-
losophy can contribute to our understanding of them. To avoid cumbersome repetition,
until further notice I will refer to the philosophy that deals with such issues, philoso-
phy of mind and language, simply as philosophy or sometimes cognitive philosophy
(on the model of cognitive psychology).
Attitudes to work on cognition done using philosophical tools often take one of two gen-
eral forms, one dismissive, the other baffled. There are two important variants of each. All
 A. Brook ⁄ Topics in Cognitive Science 1 (2009) 219

four are actual reactions that I have encountered but I will not name names. The first dismis-
sive form goes like this:

Philosophers mounted some interesting speculations about the mind in times past but we
are now in a position where we can get out of the armchair and do real science on these
things. Philosophy, imaginative and entertaining though it can be, has been relegated to
the dustbin of history. There is still something to logic and maybe ethics but the rest of
philosophy has been superceded by science.

This view of philosophy is very widely held among cognitive researchers. Here is a
variant:

You philosophers with your relentless pursuit of the big picture exhaust me. What are the
research payoffs? What we need at this point in time is disciplined work on specific
issues, not big pictures painted in broad strokes. Even those of you who try to be interdis-
ciplinary and responsive to what is now known bite off more than any mortal can
currently chew.

The key idea embedded in both variants of the response is that there is nothing distinctive
to what philosophers do, logicians and ethicists maybe excepted. Philosophy is just specula-
tive armchair science.
There is, however, an important distinction between them. The first variant takes cogni-
tive philosophy, most of it anyway, to be doing exactly what science does now, only not
very well. The second takes it, some of it anyway, to be doing something that science does
relatively rarely, namely, integrate results in a bigger picture. The difference can be brought
out by reference to the generate-and-test picture of science. On the generate-and-test picture,
the work of science is to generate hypotheses and then test them to discover which ones
remain standing when faced with data. (Reichenbach and then Popper captured this picture
in the distinction between the context of [hypothesis] discovery and the context of [hypothe-
sis] justification). To these two add a third activity, namely, interpretation. The job of inter-
pretation, broadly, is to make sense of the results of generate-and-test. Put in the language
of these distinctions, the first variant views much of philosophy as generate without test, that
is to say, discovery without justification.4 And the second views at least part of philosophy
as premature attempts at broad, integrative interpretation.
Nor is it clear that the two things of which philosophy stands accused here are entirely
bad things. Even if philosophy is just speculative hypothesis generation in the generate-
and-test process, your view of the merits of this activity will hang on whether you believe
that the hypotheses afoot in cognitive science open up all the important alternatives. In
the 2,500 years that philosophers have been speculating about the mind, they have can-
vassed an extremely wide range of possibilities. Some of them may suggest important
hypotheses about otherwise-puzzling data that current researchers have not even thought
of, let alone tested. Among others, Prinz (2002) says this about empiricism, Chomsky
(as recently as 2007) and Fodor (1975) say this about rationalism, and Kitcher (1990),
220 A. Brook ⁄ Topics in Cognitive Science 1 (2009)

Brook (1994), and others say this about the Kantian tradition (Kant, 1781 ⁄ 7). Philoso-
phy’s speculative hypotheses may expand the range of interesting hypotheses about partic-
ular bodies of data considerably.
Your view of the second variant will hang on whether you agree with Newell (1973)
when he urged nearly 40 years ago that we need to do more than generate-and-test, more
than find new effects. We need to build big, generative theories that can tie together the
thousands of effects that we have now identified.
The baffled form recognizes that often philosophical work in cognitive science at least
appears to be quite different from other kinds of work on cognition, indeed from science in
general—and is puzzled. Not infrequently the reaction will focus on the techniques used in
cognitive philosophy that are the most unlike those used elsewhere in cognitive science.
Thought experiments are a leading example. The reaction then goes something like this:

Why are philosophers interested in thought experiments, intuition pumps as Dan Dennett
(1991) calls them? Thought experiments at best explore possibilities. Why worry about
what is possible? How could such a worry contribute to the generation of knowledge?
What we should be doing is discovering what is actually going on in cognition. For this
work, thought experiments are useless.

One finds the same reaction to reductio ad absurdum (reduction to absurdity) arguments,
hang-ups about clarity of concepts, and so on. The people reacting this way do find some-
thing distinctive in philosophical work in cognitive science—but do not see why anyone
would want to do these things or think that doing them might contribute to progress in cog-
nitive research. Here is a variant of this reaction, to do with concepts:

Philosophers spend their time worrying about concepts. Why? The concepts of cognitive
science are mostly just fine. What we need is to get on with discovering the facts.

I have treated these two as variants of a single reaction because thought experiments are
often used as a tool for investigating concepts.
For the second variant to hold water, it would have to be possible to do good investigation
of the facts without paying attention to the concepts with which one is describing and cate-
gorizing the facts. Often such a separation is not possible. But if it is not, thought experi-
ments are more closely linked to investigation of the facts than is generally thought.
Again, it is not clear that exploration of thought experiments and analysis of concepts are
bad things. We will consider thought experiments separately later. The suggestion that phi-
losophers’ interest in concepts is baffling is itself a bit baffling. It is widely recognized that
the conceptual apparatus of cognitive science is not in good shape. We have dozens of terms
for memory, for attention, for consciousness, and for many other things of central interest to
us. Each approach to cognition has its own proprietary terminology that is often mysterious
to other approaches. We use the word ‘representation’ to name two very different kinds of
thing, ‘attention’ to name three, ‘consciousness’ three, ‘information’ four, and so on. Our
concepts are just fine? Not likely.
 A. Brook ⁄ Topics in Cognitive Science 1 (2009) 221

3. Methods used to do philosophy in cognitive science

Some of the methods that cognitive philosophers use are baffling for good reason. Philos-
ophy in cognitive science does not do experiments, it is not computational, it seldom makes
use of detailed findings about the brain—it seldom does any of the things that other cogni-
tive researchers do most of the time. So how does it proceed?
Concerning methods in philosophy, there is something to all four of the reactions that
we just explored. Yes, some philosophical work, especially in the philosophy of mind
and language, generates and argues for hypotheses. In connection with the mind, this
work goes back to Descartes (the mind is not the brain), indeed even to Aristotle (the
mind is the living form of the body). And yes, some philosophers have not had as much
interest in testing as one would like, preferring to look to arguments and intuitions to
support their claims. In philosophy, sometimes imaginative appeal actually counts for
more than justification. Yes, some philosophical work consists of broad integrative inter-
pretations. Yes, thought experiments play a central role in some philosophical work,
especially in the philosophy of mind, and it is true that the nature and merits of that role
are none too clear. And yes, people with philosophical training tend to pay more atten-
tion to the conceptual toolkit of cognitive science than is common in those with other
kinds of training.
In an introductory way, here is what each of these methods is like:
1. Speculative hypothesis generation. There is nothing wrong with speculative hypothesis
generation as such. Indeed, as all hypothesis generation consists in the application of
the imagination to some group of facts, all hypothesis generation has a speculative ele-
ment to it. If so, there is also nothing distinctive to those with training in philosophy in
this work. There is little speculation in the context of justification but the context of
discovery is full of speculation.
2. Integrative interpretation. The activity of interpreting tested hypotheses is a large part
of what the philosophical contribution to cognitive science consists of. One of the roles
of philosophy has always been to show how ‘‘things in the broadest possible sense of
the term hang together in the broadest possible sense of the term,’’ as the great philoso-
pher of science Wilfrid Sellars (1963) once put it.
The results of these activities are theories and models offered by philosophers similar to
theories and models offered by others in cognitive science. Indeed, Quine (1953), Sellars
(1963), Castañeda (1980), and others take most of philosophy to be like this, including the
philosophy of mind and language. The main difference is that philosophers tend to go after
bigger and sometimes more abstract objects than researchers with other backgrounds: in
cognitive research, representation as a whole rather particular kinds of representation, ratio-
nality as a whole rather than particular activities of reasoning well, the nature of explanation
in cognitive science as a whole rather than how to explain a given phenomenon before us.
So far, except for level of generality and abstraction, there is nothing distinctive to this
methodology. However, philosophers’ interpretations are generally aimed at results
achieved by others. This sometimes confers advantages of breadth and objectivity.
222 A. Brook ⁄ Topics in Cognitive Science 1 (2009)

3. Exploration of thought experiments. Thought experiments consist of imagined manipu-

lations of imagined scenarios. Philosophers (and, as we will see, others) sometimes
claim that one can reach substantive conclusions by using them. We will return to this
topic.
4. Analysis of concepts. Philosophically grounded work in cognitive science has spent a
lot of time clarifying concepts and making recommendations for how concepts should
be used. Here is an example that shows why.
Pylyshyn and Storm (1988) have shown that humans can track a number of objects at the
same time. They suggested that we use what Pylyshyn calls visual indexicals to do so. How
does such tracking relate to attention? There are two options: (a) It is itself a kind of atten-
tion, albeit less focused and less conscious than a lot of attention. (b) It is a precursor to atten-
tion, a way of fixing on objects so that we can come to pay attention to them. Which is best?
Notice two things. First, this is not a trivial issue. If we say that tracking is a form of atten-
tion, then there is a form of attention that is dispersed over a number of objects and not fully
conscious. And theory of attention will have to account for it. If on the other hand we say that
only something subsequent to the kind of object tracking that Pylyshyn has in mind is atten-
tion, then we are free of these burdens. Second, the issue does not concern the facts and could
not be settled by reference to the facts. It is about the best way to group observed phenomena
under a word. Is the more or the less expansive use of the word ‘attention’ simpler and clea-
ner? Which better captures what us interests here, our reasons for using the word? Which
alternative is more neutral in the light of possible theories in the neighborhood? And so on.5
Philosophers do a lot of this kind of work. Though it is not distinctive to philosophy—
having a clean, trouble-free toolkit of concepts is a requisite of good science and so of inter-
est to anyone doing science—training in philosophy tends to makes one better at it. Also, it
could be suggested, the rest of cognitive science suffers from not doing enough of it. In the
context of this suggestion, it is striking that even when collaborative work between
philosophers and others has occurred, as it has, for example, on concepts and how we
process them, this work often does not affect cognitive science elsewhere, in this case the
stifling profusion and confusion of concepts in cognitive research.
Moreover, this kind of investigation is not limited to words. The investigation of the
semantic properties of different types of explanation, the investigation of how various scien-
tific (and perhaps other) activities use a given word, and perhaps some other things deal with
the same kinds of issues. And thought experiments are one of the main tools used in this
work, though they are used elsewhere, too, as we will see.

4. Thought experiments in cognitive philosophy

Thought experiments deserve some special attention. The activity of exploring them
looks very peculiar to those doing normal science and is widely misunderstood.
Thought experiments, we said, are exercises of the imagination. Thus, they contrast with
hands-on experiments.6 In a thought experiment, we imagine, that is, represent, a scenario,
 A. Brook ⁄ Topics in Cognitive Science 1 (2009) 223

rather than manipulate a scenario that actually exists. And we are interested in figuring out
what is possible rather than what is actually the case. Some of the most famous thought
experiments in cognitive science are Searle’s Chinese room, Putnam’s twin earth, Jackson’s
Mary the color–blind color scientist, Dennett’s qualia impasses, and Chalmers’ zombie
thought experiments. A major source of people’s bewilderment about philosophers and
thought experiments is that philosophers seem to hold that merely imagining scenarios could
reveal things of importance.
Searle’s (1980) Chinese room is the most famous thought experiment in cognitive
research. Someone who knows no Chinese is put in a room. Sheets of paper with shapes on
them come in through a slot. The person has an inventory of other shapes and a huge rule-
book linking shapes to shapes. For each shape that comes in, she identifies and finds the
linked shape(s) and shoves it (them) out a second slot. Unbeknownst to her, the shapes com-
ing in encode questions in Chinese and the shapes going out are answers to these questions.
What this is supposed to show is that what the person who knows no Chinese does in the
room is all that a computer processing symbols by their physically detectable properties
could do.
Twin earth thought experiments go like this (Putnam, 1975). Imagine a person here
on Earth, Adam, and his completely identical twin, Twadam, on experientially indistin-
guishable Twin Earth. Adam and Twadam both use the word ‘water’ and they use it in
situations that are experientially indistinguishable. Yet on earth what is called ‘water’ is
H2O, on twin earth it is XYZ. Does the word ‘water’ as used by Adam and by Twadam
have the same meaning? Evidently not. Yet everything in their heads is the same.
Hence, in Putnam’s memorable phrase, ‘‘meanings just ain’t in the head’’ (Putnam,
1975, p. 227).
The thought experiment about Mary the color scientist goes like this. Mary is a wonderful
color scientist. Indeed, she knows absolutely everything there is to know about color experi-
ence. Yet she has never seen color. One day the barrier is removed and she sees color for
the first time. It would seem that she would gain a new item of knowledge: what it is like to
experience color. Hence experience is not ... (draw your favorite conclusion). (Frank
Jackson created this thought experiment but no longer finds the radical implications in it that
he once did).
Here is a leading example of a qualia impasse, Dennett (1988, 1991). Chase and Sanborn
both notice that they do not like their favorite coffee as much anymore. Chase says that the
coffee tastes the same but he does not like that taste as much as he used to. Sanborn says,
no, he would still like that taste as much but the coffee no longer tastes the way it used to.
Since there would seem to be no way in which this putative difference could make a differ-
ence, we are invited to ask ourselves whether there is a real difference here.
Chalmers (1996) mounts zombie thought experiments to convince us that we can imagine
a creature behaviorally, cognitively, and even physically exactly like us except that it is not
conscious. If so, consciousness does not consist of anything behavioral, or cognitive, or
(nonconscious and) physical.
Thought experiments are used more widely in science than is generally recognized. Phys-
ics, for example, is famous for its thought experiments (on thought experiments in science,
224 A. Brook ⁄ Topics in Cognitive Science 1 (2009)

see Brown, 1991; Horowitz & Massey, 1991; and Sorensen, 1992). Schrodinger’s cat and
Galileo’s tying a smaller and a bigger piece of matter together are two of the best known.
Schrodinger argued, against the indeterminacy interpretation of quantum mechanics, that a
cat in a box had to be in some determinate state even if we do not know what it is. Galileo
argued, against the Aristotelians, that if Aristotle was right and a smaller mass A falls slower
than a larger mass B, then if we make up a new object C by joining A and B, C will have to
fall both faster and slower than B. This was supposed to eliminate Aristotle’s hypothesis,
with no experiments needed. Thought experiments played a key role in Einstein’s discovery
and formulation of relativity theory.
Sometimes psychological researchers use thought experiments, too. For example, some
research into reasoning starts with getting the subject to do a thought experiment. The sub-
ject is asked to determine whether more words begin with ‘r’ than end with it, for example,
or to determine which of two alternatives is more probable. Presumably the way in which
they do this is by imagining something and then using what they have imagined to answer
the question.
Equally, linguistic theory is full of thought experiments. In linguistic theory, thought
experiments usually concern much smaller matters than in philosophy—strings of words—
and the objective is to test intuitions of grammaticality or meaningfulness. ‘‘Does this string
sound grammatical?’’ or ‘‘Could this string mean such-and-such in the imagined context?’’
are the kinds of question asked. Chomsky’s invitation to imagine the string, ‘Colorless green
ideas sleep furiously,’ to see if it seems grammatical is the most famous example. Smaller
to be sure, but these too are thought experiments.
There are differences between thought experiments in physics, psychology, and linguis-
tics and the kind of thought experiment that philosophers do. In physics, not only is the
thought-experimental situation clear, but also its implications are clear, too, many of them
anyway. The latter is notably not true of philosophers’ thought experiments. And in linguis-
tics and psychology, the thought experiments are done by the subjects, not by the research-
ers, and are meant to generate data, not sort out what is actual or possible with respect to
data. (Brown [1991] says that they are real experiments done in the mind, not thought exper-
iments at all.) Also, in the hands of philosophers, thought experiments sometimes play a
normative role, which is not true elsewhere. Think again of the thought experiments in
reasoning research that we mentioned. Psychologists get subjects to do these exercises to
find out how they actually reason: what mistakes they make, what produces these mistakes,
and so on. When a philosopher runs a thought experiment about reasoning, her interest is
different. She wants to find out what good reasoning consists of. Nonetheless, thought
experiments are not unique to philosophers, not even inside cognitive science. However
peculiar they may seem to some people, they are used in science.
It could still be true, of course, that thought experiments play a bigger role in philosophy
than in any other part of cognitive science. That they do. Indeed, they are central to some
philosopher’s work. Equally, no other discipline uses them to study normative issues. None-
theless, thought experiments are not unique to philosophers.
What can thought experiments do for us? This is a topic to which I will return if there is
an opportunity later in the theme, but here are some of the claims made on their behalf:
 A. Brook ⁄ Topics in Cognitive Science 1 (2009) 225

1. Thought experiments can isolate crisp examples of a phenomenon under

investigation.
2. Thought experiments can tell us what we initially take something to be like and can
sometimes play a role in us deciding what we should take something to be like.
3. Thought experiments are often central to hypothesis generation.
4. Thought experiments can sometimes play a role in hypothesis testing and elimination.

The last claim is more contentious than the other three. In summary, thought experiments
are quite different from hands-on experiments. However, they play a key role in the clarifi-
cation and reconstruction of the concepts used in doing hands-on experiments and in the
generation of hypotheses for hands-on experiments to test. And they may sometimes play a
role in hypothesis elimination.

5. Philosophy of cognitive science

So far, we have mainly discussed the kind of philosophical work that is part of cognitive
science and the methods that researchers use when they do it. We turn now to philosophy of
cognitive science. As some of the papers to come in the theme deal with this role for philos-
ophy splendidly, I will keep my remarks brief.
Unlike the reaction to philosophy in cognitive science that we examined earlier, few have
serious doubts that philosophy of cognitive science plays an important role. The range of
philosophical questions that can be asked about cognitive science is almost limitless. (From
here on, the term ‘philosophy’ will no longer be short for ‘philosophy of mind and
language,’ as it was above). A sample of some of the important ones:
• Do cognitive models such as ACT-R merely fit the behavioral data or can they capture
the actual structure of human cognition (Fodor’s 1968, and Pylyshyn’s 1984 weak and
strong equivalence)? Closely related, could AI systems or robots operate as we do or
will they always be just engineering?
• What kinds of explanations work best on cognition, particularly in light of the massive
complexity and interconnectedness of the human brain and the inherently statistical,
rather than rule-like, nature of complex behavior (Bechtel, 2008; Bechtel, forthcom-
ing)?
• When are correlations merely correlations and when can they be taken to reflect a
causal or structural connection (Hardcastle, 1996, Ch. 2)?
• What does it take to confirm or refute a theory or model of cognition (see Thagard
[2000] on the role of coherence in cognitive theory building, for example)?
• Can studies done in the highly artificial setting of a laboratory reveal how cognition
works in more natural settings or do we need to study cognition ‘‘in the wild’’ to
achieve such understanding (Clark, 1997)?
• Does the structure of human cognition tell us something about the structure of all possi-
ble cognitive systems or is our cognitive structure just a tiny fragment of the space of
possible cognitive systems? (Chomsky [2000, p. 16, and many other places] holds that
226 A. Brook ⁄ Topics in Cognitive Science 1 (2009)

the latter is true of human languages at any rate. If this is true of language, how could it
not also be true of the rest of cognition?)
• While the notion of computation provided a useful metaphor and operational frame-
work for cognitive science in the early decades, is human cognition computational in
anything like the way any computer, serial or parallel, is? (Searle, 1980; Fodor, 1983,
2000; and many others say no). What implications, if any, does Gödel’s incompleteness
theorem have for this question? (Note: The answer to this last question probably will
have implications for the whole formal systems approach to human cognition, particu-
larly prominent at the moment in theoretical linguistics.)
• How can we integrate the multitude of different approaches to cognition into a single,
unified picture (Hardcastle, 1996, Chs. 6 and 7; Dawson, 1998, Ch. 8 is a penetrating
case study)?

Questions such as these not only raise important issues about guidelines and frameworks
for doing good cognitive research, but they also raise important meta-questions about the
goals of a science like cognitive science in the first place.
Equally, philosophical reflections on cognitive science can take a number of forms. What
I have tried to do in this paper, namely, understand how an activity in cognitive science
works (philosophy in this case), is one form. Another is to apply general philosophy of sci-
ence to cognitive science to determine what kind of science it is and what works in it
(Bechtel, forthcoming; Pylyshyn, 1984; Dawson, 1998; and Bechtel, 2008 are some impor-
tant examples). A third is what we earlier called the context of interpretation. Often it is
unclear what an experimental finding means. What are its implications for the question
before us? Does it help with other questions? ... and so on. A fourth consists of integrating
results attained by different ways of doing cognitive research (again, Hardcastle, 1996,
Chs. 6 and 7 and Dawson, 1998, Ch. 8). This is once again Sellars’ ‘‘how things in the
broadest possible sense of the term hang together in the broadest possible sense of the
term.’’ Yet a fifth is to make and defend claims of various kinds about how it should work.
Indeed, in philosophical reflections on cognitive science, how it does and how it should
work are often not far apart. Investigations of shoulds and should nots, goods and bads,
oughts and ought nots are normative investigations.
What methods do philosophers use to do such work? This is a big and largely unstudied
question, one much in need of some unhurried exploration. Here I will restrict myself to
investigation of normative questions, as this is the part of philosophy of cognitive science
most distinctive to it.
Normative investigations are sometimes thought to be restricted to ethics and aesthetics.
Certainly ethical issues arise in cognitive science. In particular, applications of cognitive
science, which can vary from human computer interfaces and virtual realities to pedagogy
to prosthetic brain implants and cognitive robotics, raise all kinds of questions about rights
and responsibilities. If biotechnology is controversial, ‘cogno-technology’ will be much
more so. Indeed, cognitive science probes such ancient and central questions as what it is to
be human, whether we have free will, and what the boundaries of the self are. There is lots
of work for philosophers to do on ethical issues in cognitive science.
 A. Brook ⁄ Topics in Cognitive Science 1 (2009) 227

That said, normative questions in cognitive science are not limited to ethics and adjoining
philosophical fields. Philosophy of science also concerns itself with norms, especially the
part of philosophy of science that studies knowledge—such things as norms for good evi-
dence, for warrant, for adequacy of theory, for good explanations, and so on. Such investiga-
tions are clearly important to cognitive science.
Norms, what ought to be, cannot be settled by studying what is. So scientific method,
which consists of description and theory of what is, cannot by itself resolve normative ques-
tions, not even the normative questions that arise about science itself. If normative work on
cognitive science is essential, there is also a case for holding that philosophers’ training in
how to think about norms makes a contribution that is both distinctive and irreplaceable.
Other disciplines may explore what explanations we in fact use, how we in fact access evi-
dence for purposes of belief formation, how we in fact reason about probabilities, and so on.
However, the activity of investigating what explanations we should use, how evidence
should constrain belief, how we should reason about probabilities cannot be read off any
facts about how we do in fact do these things.
As an example of how the descriptive ⁄ theoretical and the normative mix in philosophy of
cognitive science, consider work on explanation in cognitive science. Often this work is, to
begin with, broadly descriptive, aimed at questions such as: What styles of explanation do
cognitive scientists use? How do they work? But before long a normative dimension often
slides in: What styles of explanation should cognitive scientists use? What styles of explana-
tion might get us somewhere and which probably would not?
How do philosophers build such normative assessments? By what methods, by what
kinds of reasoning, can we validly ⁄ justifiably ⁄ adequately assess what we ought and ought
not do? Even this question about the methods of one kind of philosophy of cognitive science
is a big topic; I will restrict myself to just two suggestions. At least in epistemic contexts,
two main methods are

1. Inferring norms from general principles of some kind, principles that are themselves
rationally compelling, and
2. Shaping norms to serve our deepest epistemic interests.
In connection with epistemic norms, principles that preserve truth or that proportion
degree of belief to degree of probability might be examples. Occam’s Razor (postulate no
more entities than are needed to explain something) and simplicity (postulate the smallest
number of principles needed to explain something) might be others. Relevant interests might
include our interest in prediction, in control, in understanding structure, in knowing origins,
and so on.
Assessing normative claims against general principles of rationality or deep-seated epi-
stemic interests does seem to be a method distinctive to philosophical training. Indeed, when
cognitive scientists from other backgrounds engage in this sort of epistemology and philoso-
phy of science, they are no longer doing science, strictly speaking.
Thought experiments often have the purpose of helping us to help settle normative
claims. When we mount thought experiments to investigate concepts, styles of reasoning,
228 A. Brook ⁄ Topics in Cognitive Science 1 (2009)

and so on, we want the result to be good concepts, good styles of reasoning, and so on. That
is to say, we are interested in normatively reconstructing our conceptual tools so that they
serve our epistemic interests better, not just in finding out what is built into them already.7

6. Concluding remarks

I have tried to construct an overview of the kinds of contributions to cognitive science

made by those with philosophical training—both philosophy in cognitive science and phi-
losophy of cognitive science—and of some of the main methods used to make them.
Final note. Even if philosophy lacks distinctive methods, it could still play a distinctive
role in cognitive science. In particular, philosophy could have distinctive preoccupations.
And indeed it often does. Where experimentalists are interested in whether a claim is true,
philosophers tend to be more interested in how concepts hang together, what the possibili-
ties are, and so on. I am reminded of the 1950s television show Dragnet. Like Jack Webb,
the lead detective in the show, an experimentalist would say, ‘‘Just the facts, ma’am, noth-
ing but the facts.’’ A philosopher would be more likely to ask, ‘‘Wha’d’ya mean, ma’am,
wha’d’ya mean?’’ If an experimentalist does turn to look at her conceptual toolkit or stands
back to consider the general nature of what she is doing, this would be a sideline for her,
maybe because something in the toolkit is not working well. For philosophers, doing such
things is their occupation.
So, what could and should the role of philosophy in and of cognitive science be? Let the
show begin!8

Notes

1. Pylyshyn trained as a psychologist but has made prodigious philosophical contribu-

tions.
2. Much the same could be said of linguistic theory. In the form of the towering contribu-
tion made by Chomsky’s theory of syntax, it too was central in the early days and it
too has not settled into a stable, fully interactive position in cognitive science.
3. And not messing with Mr. Inbetween? I am not sure what that would be. The reference
is shamelessly stolen from Fred Dretske (1995).
4. This failing is precisely what experimental philosophy aims to fix.
5. Jackson (1998) is one of the very few philosophers who discuss work of this kind on
concepts. Kripke (1972); Nozick (1981); Cohen (1986); and Dummett (1993) offer
related discussions.
6. There is no short yet completely adequate way to mark the distinction. Question-beg-
ging options that do not work include ‘real experiment,’ ‘physical experiment,’ ...
7. Our discussion does not exhaust the range of methods used by philosophers to study
cognition. One method not mentioned so far is the view that philosophy is or should
be the untying of conceptual knots, an idea associated particularly with Ludwig
 A. Brook ⁄ Topics in Cognitive Science 1 (2009) 229

Wittgenstein (1953). Bennett and Hacker (2003) attempted to show its efficacy in cog-
nitive neuroscience but the attempt largely failed. I will not discuss it further. Another
method not mentioned so far is the attempt to study the mind by identifying standards
that a system must meet to be a mind. Standards of minimal rationality and certain
intersubjective standards are popular. This approach was introduced by Davidson
(1973) and Dennett (1973). In more recent times, McDowell (1994) and Davidson
(2001) have championed it. Sometimes called the normative model of mind, this
approach played a role in cognitive ethology for a while (Seyfarth & Cheney, 2002)
but has also not had much influence on general cognitive research, so I will not discuss
it further, either.
8. My thanks (in alphabetical order) to Bill Bechtel, Wayne Gray, Jo-Anne LeFevre,
Heidi Maibom, Rob Stainton, and Chris Viger for very helpful comments.

Acknowledgements

This paper is a distant descendant of Brook, A. (1999). Does philosophy have distinctive
methods to offer cognitive science? Proceedings of the 21st Annual Conference of the Cog-
nitive Science Society (New York: LEA), pp. 102–108. The discussion of thought
experiments draws on Brook, A. (2006). Thought experiments. In A. Barber and R. Stainton
(Eds.), Encyclopaedia of language and linguistics. Amsterdam: Elsevier.

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