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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