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354
Ethics
January 2 13
Churchland, Patricia
S
Braintrust: vVhat euroscience Tells
Us
about iHomlity.
Princeton, NJ: Princeton University Press, 2011. Pp. 273. $24.95 (cloth).
In Braintrust: vVhat
euroscience
Tells
Us
about Morality Patricia Churchland sets out
to synthesize and explain recent developments in the biological sciences that
shed
light on the
nature
of
human
morality.
Churchland
casts a wide
net
and covers a
lot
of
ground. After a brief introduction, seven dense chapters examine a range
of
complex topics, including evolutionary constraints on social and moral behavior;
the evolution of the mammalian brain (with particular emphasis on
hormones
such
as
oxytocin); the neurobiological basis of human cooperation (again with reference
to oxytocin); the genetic blueprint for moral cognition and
the
evidentiary status
of
specialized moral modules;
mirror neurons
and
other
neurocognitive mechanisms
of
mental
state attribution;
the
proper place
of
rules, norms, and laws
in
a natu
ralistic ethics; and religion and morality.
The
treatment of
these subjects
is
generally informative and often quite illu
minating, albeit occasionally superficial. Churchland writes elegantly and presents
a clear, distinctive,
and
forceful viewpoint
on
the science of morality, which draws
inspiration from Aristotle,
Hume,
and Darwin. Her principal thesis, that moral and
social values are rooted in the neurobiology of care, trust, and cooperation, deserves
to be taken seriously by scientists
and
philosophers alike. In this review, I focus
on
three perceived weaknesses
of
Churchland's stimulating book that likely
will
be
of particular interest to philosophers: her interpretation
of
Hume,
her
skepticism
toward innate moral principles, and her ueatrnent
of
moral rules. I
then
conclude
by
making a
few
brief observations
about the
general significance of
Braintrust.
Churchland begins (4-8)
and
ends (201-4) her book with Hume, endorsing
Hume s naturalism and offering a fuirly conventional reading of his influential
passage in the
Treatise
warning against deriving normative statements exclusively
from descriptive statements.
Her
discussion of
the
is-ought passage
is sound
as far
as it goes,
but
it arguably does
not
go
far
enough.
The
context of
this famous
passage was
not
merely Hume s naturalism but also his internalism about the na
ture and
origin
of
moral distinctions.
Churchland
discusses
the former
but not
the latter-a curious omission in a book offering a brain-based perspective on hu
man morality.
True,
Hume claimed that moral distinctions
are
not derived from
reason because moral distinctions motivate and reason
is
motivationally inert. Yet
he
also
argued,
more significantly in this context, that
moral
principles connect
ing fact patterns with verdicts are not among the information transmitted to the
mind
through
the senses. These principles must, therefore, be contributed
by
the
individuals engaged in moral perception.
The
principles
are
located in
them
not
in the mind-independent objects of the external world, and they supply the crucial
but
often hidden major premises
of
their intuitive moral judgments. The proper
focus of moral philosophy
is
thus the moral nature of human beings and
the
sentiments of blame and praise they apply intuitively to the stimuli that occasion
moral judgments,
not the eternal fitness
of
things
or
the abstract relations
of
ex
ternal objects. It
is
these sentiments, not outside entities, that introduce the distinct
concept of
ought into
the
theory
of
moral cognition.
By
contrast,
the phenomena
that stimulate moral judgment
can
be rendered in terms
of
features-passions,
motives, volitions, and so forth-that
are
purely descriptive.
If one
is
convinced by
Hume
and follows
him
in locating moral principles
inside the head,
then
the question naturally arises: Where do they come from?
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Book
Reviews 355
s
Hume asks in the
Treatise
whence do these principles arise in the human mind?
In her discussion of innateness, Churchland (103-17) neglects to consider
Hwne s
own response to this question
and
thus
endorses
a very
un-Humean
answer.
In
a nutshell, Hwne argued that because individuals are prepared to recognize an in
finite
number and
variety of moral duties, the precepts from which these duties
arise cannot be derived from experience alone. Instead, one must
seek
their ori
gin in more general principles, a type of instinctive knowledge that constitutes
part of the original fabric of the human mind. y contrast,
and
again quite
surprisingly,
Churchland
expresses skepticism
about
whether any hypothesis of
innate moral
principles makes sense.
Noting
that Plato was among the first to
argue
that human
beings possess innate moral knowledge, she initially suggests
that
to
defend
a similar conclusion in a
modem
scientific framework
one
needs
to identify the genes involved, show how they help organize neural circuitry, and
then show
the
relation
of the
circuitry to
the
particular behavioral trait
at
issue
{105). Recognizing that this may be asking too
much-few
i any cognitive capac
ities are
understood
at this level of scientific detail-Churchland
then
canvasses
other arguments for innate knowledge, finding all of them lacking.
The careful reader
will
notice, however, that neither in this critical chapter nor
elsewhere in
raintrust
does Churchland directly address the epistemological prolr
lem that engaged Plato
and
that has motivated generations
of
philosophers
and
cognitive scientists ever since: How do we know so much based on so little?
Nor
does
she squarely confront the argument from the poverty of the stimulus, the primary
nativist response to Plato'
s--and
Hume 's--problem. Perhaps even
more
surpris
ingly, Churchland does not consider any of the available evidence from infant cog
nition, developmental psychology, or
other
parts of cognitive science that appears
to lend support to various forms of moral nativism. Instead, she more or less skips
ontogenetic development altogether. She also repeatedly confounds the issue
of
innateness with three related, but distinct, topics: universality, modularity, and im
penetrability.
The
result
is
a critical discussion
of
innateness that largely bypasses
many of the most salient problems in moral epistemology and tends to obscure
the most relevant scientific discoveries that
bear on
them.
Poverty of the stimulus arguments are a species of
computational
argument.
Typically, they claim that in order to understand how the brain processes informa
tion in a given domain,
one
must recognize the crucial gap-filling contribution of
the brain itself. Thus, these arguments generally do not focus
on
particular behav
iors
or
behavioral traits as such but, rather, focus on the cognitive structures
that
enter
into behavior and, more broadly, the second-order cognitive capacities that
must be postulated in order to explain how these first-order structures
are
acquired
by each individual.
The
particular computations to which these argwnents indi
rectly refer can be conceived
on
the model
of
rules
or
rule following, but care
must be taken to dissociate any such conception from claims about the ons ious
possession
or
application
of
rules. Rather, the dominant trend in the cognitive sci
ences is to asswne that these mental ntles are known and operate unconsciously
and to
proceed
with the challenging task
of
explaining the gap between the rich
outputs of cognition and the sparse and ambiguous information available through
the senses,
whether
this underdetermination involves perception
or
knowledge
acquisition.
Unfortunately, in
her
chapter
on
rules {163-90), Churchland neglects to draw
this fundamental distinction. Instead, she repeatedly assumes that the only rule-
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56
thics
January 2 13
based hypothesis worth analyzing in this context involves the conscious, rational
application of moral rules (
166).
For example, she criticizes the
popular
notion that
there exists a specific set
of
discursive rules
that
one
carr[ies]
around in
memory
and
literally consults when making moral
judgments
(185). This s an easy target,
but
its implausibility does
not
imply that intuitive moral judgment does not de
pend on the application
of
rules.
These
rules may not
be
discursive, memorized,
or
literally consulted,
but
the best explanation of the properties of moral
judgment
suggests that they do enter into moral cognition all the same. In short, unconscious
computation, not conscious application of rules, s the more significant rule-based
proposal to evaluate in this context Disappointingly, Churchland does
not
consider
this hypothesis.
Churchland s
failure to
engage
with
an
internalist
conception
of
moral
cog
nition that posits an
innate
basis for the acquisition of unconscious rules and the
representations over which they compute may be the most conspicuous weak
ness of
Braintrust.
The most obvious strengths are the
author s
unapologetic nat
uralism; her
deep
knowledge of genetics, neuroscience, and evolutionary biol
ogy; and
her keen
appreciation for the complexity, dynamism, and explanatory
potential of these fields.
Churchland
s convinced that one cannot make prog
ress in uncovering the
nature
and origin of human moral values without under-
standing a fair
bit
of science.
On
this general point, she seems correct and makes
a persuasive case. The topics she surveys and
the
literatures from which she draws
may intimidate some readers, but the
trail
she blazes will be empowering for
others, particularly philosophers who wish to
break
free from the conventional
limits
of their
discipline.
In Churchland,
they will find an
expert
guide and an
inspiring role model.
Her
lucid
and detailed
chapters on the neurobiology of
caring
(27-62), cooperation
and trust
(63-94), and
the theory of
mind (118-62)
alone are worth the price of admission.
Yet ethical naturalism comes in many varieties. Churchland s hardly alone
in thinking
that Hume and
Darwin were essentially
correct
in locating
the
ori
gin of morality in a moral sense or conscience that nature, not God, has made
universal in the species (192-93).
t
does not follow that genetics, neuroscience,
and
evolutionary biology are the best sources from which to draw to carry forward
their central insights. As these fields are currently conceived, they may be able to
contribute relatively little. Certainly they seem unlikely to accomplish as much as
a collective effort by philosophers, cognitive scientists, and other researchers to
understand how the mind processes information in the moral domain within a
computational-representational framework and, only
then,
to relate that
under-
standing to what
s
known
about
genes, brains,
and
evolution.
The general
sig
nificance of
Braintrust
then, may rest more on the particular conception of the
science of morality it seeks to promote than
on
its naturalism per se.
For readers
interested in learning more about the basic architecture of the
brain
or the neu-
robiology ofcare and attachment, however,
Churchland s
book s a
good
place to
start and will serve as a valuable resource. There s much to learn about these
topics, and Churchland s a gifted teacher.
jOHN
MIKHAIL
Geargetown
University