## 1. Overview: Basic Issues, Questions, and Distinctions



Very little in the study of human life has been left untouched by
developments in evolutionary biology, and inquiry into the nature of
morality is no exception. With the recognition that we, like all other
living things, belong to a species that has evolved through natural
selection comes the acknowledgement that evolutionary processes have
likewise shaped us deeply. How deeply?



Evolutionary explanations are commonplace when it comes to questions
about our physiological nature--why we have opposable thumbs,
say, or a bipedal posture. But even a brief look at other animals
affords countless examples of adaptive *psychological* and
*behavioral* traits as well--appetites for food or sex,
fear responses, patterns of aggression, parental care and bonding, or
patterns of cooperation and retribution; and these traits are likewise
often best explained as biological adaptations, i.e., traits that
evolved through natural selection due to their adaptive effects. (We
will go through a striking example involving cooperative behavior in
section 2.2.) This raises the question: to what extent might human
psychological and behavioral traits similarly reflect our own
evolutionary heritage?



When it comes to morality, the most basic issue concerns our
*capacity for normative guidance*: our ability to be motivated
by norms of behavior and feeling through *judgments* about how
people *ought* to act and respond in various circumstances
(Joyce 2006, Kitcher 2006a,b, 2011, and Machery and Mallon 2010). Is
this human capacity a biological adaptation, having perhaps conferred
a selective advantage on our hominin ancestors by enhancing social
cohesion and cooperation? ('Hominin' refers, as did
'hominid' until very recently, to *Homo sapiens*
together with fossil species of ape to which *Homo sapiens* are
more closely related than we are to chimpanzees; these include the
Australopithecines, extinct species of *Homo*, etc., making up
the tribe Hominini within the sub-family Homininae.)



If so, then it would be part of *evolved* *human nature*
to employ moral judgment in governing human behavior, rather than a
mere "cultural veneer" artificially imposed on an amoral
human nature (de Waal 2006). This would be a significant result, and
it is only the beginning of the intriguing questions that arise at the
intersection of morality and evolutionary biology. Researchers are
also interested in the possibility of more specific forms of
evolutionary influence. Are there, for example, emotional adaptations
that influence the very *content* of moral judgments and
behavior, even today?



For example, many of us believe that among our various moral duties,
we have special and stringent duties toward family members. Might this
'moral intuition' be attributable, at least in part, to an
evolved tendency to favor members of one's kin group over others,
analogous to similar traits in other animals? Even where moral beliefs
are heavily shaped by culture, there might be such evolutionary
influences in the background: evolved psychological traits may have
contributed to the shaping of cultural practices themselves,
influencing, for example, the development of "family
first" cultural norms that inform our judgments. Similarly with
a tendency more generally to favor members of one's own group
(however defined) over outsiders.



The above sorts of questions, which are receiving growing attention in
the sciences, all pertain to morality understood as a *set of
empirical phenomena to be explained*: it is an empirical fact
about human beings that we make moral judgments, have certain feelings
and behave in certain ways, and it is natural for the sciences to seek
causal explanations for such phenomena. At the same time, however, it
is a very complex matter--and one often neglected outside of
philosophy--how such empirical, explanatory projects are related
to the very different sets of questions and projects pursued by
philosophers when they inquire into the nature and source of
morality.



Moral philosophers tend to focus on questions about the justification
of moral claims, the existence and grounds of moral truths, and what
morality requires of us. These are very different from the empirical
questions pursued in the sciences, but how we answer each set of
questions may have implications for how we should answer the other. As
we will see, though the two sets of issues are distinct, the
scientific explanatory projects raise potential challenges for certain
philosophical views, and at the same time attention to philosophical
issues raises doubts about some of the explanatory claims made in the
name of science, which often *rely on* controversial
philosophical assumptions. Progress in this area will not be made
either by doing moral philosophy in isolation from the sciences or by
taking morality out of the hands of philosophers and looking to
scientific inquiry in isolation. More promising would be a careful
examination of the ways in which the scientific and philosophical
projects inform each other.


### 1.1 Three Kinds of Appeal to Evolution in Evolutionary Ethics



Talk of 'evolutionary ethics' may suggest a well-defined
field of inquiry, but in practice it can refer to any or all of the
following:


1. *Descriptive Evolutionary Ethics*: appeals to evolutionary
theory in the scientific explanation of the origins of certain human
capacities, tendencies, or patterns of thought, feeling and behavior.
For example: the appeal to natural selection pressures in the distant
past to explain the evolution of a capacity for normative guidance, or
more specifically the origins of our sense of fairness or our
resentment of cheaters. (See section 2.)
2. *Prescriptive Evolutionary Ethics*: appeals to evolutionary
theory in justifying or undermining certain normative ethical claims
or theories--for example, to justify free market capitalism or
male-dominant social structures, or to undermine the claim that human
beings have a special dignity that non-human animals lack. (See
section 3.)
3. *Evolutionary Metaethics*: appeals to evolutionary theory
in supporting or undermining various
 metaethical
 theories (i.e., theories *about* moral discourse and its
subject matter)--for example, to support a non-cognitivist
account of the semantics of moral judgment (the idea that moral
judgments do not purport to represent moral facts but instead just
express emotions, attitudes or commitments), or to undermine the claim
that there are objective moral values, or to cast doubt on whether we
could have justified beliefs about such values. (See section 4.)



All three types of project have broadly to do with *how
neo-Darwinian evolutionary theory might bear on our understanding of
ethics or morality*. The driving questions, concerns,
methodologies and implications, however, differ greatly among these
three lines of inquiry.



Importantly, there are no simple or straightforward moves from the
scientific projects in A to the philosophical projects in B or C.
Arguments for or against such moves require difficult philosophical
work. Moreover, philosophical issues relevant to C can have an
important bearing on at least some of the scientific explanatory
projects in A. This puts important constraints on how much can
confidently be said in favor of such scientific explanations given
ongoing controversy over the philosophical issues.



It is, for example, a matter of live debate in contemporary metaethics
whether there are knowable *moral truths*--correct answers
to at least some questions about what is morally good or bad, right or
wrong. If there are, as many philosophers (and non-philosophers)
believe, then this will likely make a difference to the explanation of
at least *some* of our moral beliefs and behaviors. Our belief
in equal human dignity, for example, along with derivative beliefs
about the wrongness of slavery or rape, might be sufficiently
explained by our having grasped the moral truth that human beings have
such dignity and so should not be treated as "mere means"
(see section 2.4). Similarly, the belief that we have moral
obligations to mitigate suffering even among distant strangers might
be explained at least in part by our having grasped the moral fact
that pointless suffering is intrinsically bad and that this gives us
good reason to mitigate it where we can.



If this is so, then scientists will be overreaching if they claim that
"causal explanations of brain activity and
evolution...already cover most known facts about behavior we term
'moral'" (Wilson 1998, 54). Instead, a significant
amount of moral judgment and behavior may be the result of gaining
moral knowledge, rather than just reflecting the causal conditioning
of evolution. This might apply even to *universally* held moral
beliefs or distinctions, which are often cited as evidence of an
evolved "universal moral grammar" (Mikhail 2011). For
example, people everywhere and from a very young age distinguish
between violations of merely *conventional* norms and
violations of norms involving *harm*, and they are strongly
disposed to respond to suffering with concern (Nichols 2004). But even
if this partly reflects evolved psychological mechanisms or
'modules' governing social sentiments and responses, much
of it may *also* be the result of human intelligence grasping
(under varying cultural conditions) genuine morally relevant
distinctions or facts--such as the difference between the
normative force that attends harm and that which attends mere
violations of convention.



We will look in more detail later at this and other possibilities for
explaining moral judgment and behavior. The point so far is just that
there are plausible philosophical accounts of at least some moral
judgment and behavior that appeal to independent exercises of
judgment--perhaps in grasping moral truths, or perhaps just in
forming reflective commitments--rather than to causal
conditioning by evolutionary factors. There is a danger, then, of
begging central questions if we draw *general* conclusions
about "the" explanation of "our" moral thought
and behavior based on scientific considerations--as is common in
discussions of scientific work in this area. We may instead need a
plurality of explanatory models. The best explanation for deeply
reflective moral judgments may look quite different from the
explanation for unreflective psychological dispositions we share with
other primates, and there may be mixed explanations for much that lies
in between.


### 1.2 The Empirical and Normative Senses of 'Morality'



As a final preliminary point, it is useful to clear up one persistent
source of confusion in discussions of morality and evolution by
distinguishing between two very different senses of
'morality' and describing more explicitly the different
sets of questions associated with them.


1. The Empirical Sense of 'Morality'



People coming from a scientific perspective, who are interested in
*descriptive* evolutionary ethics, speak of morality as
something to be explained scientifically--as in familiar talk of
"how morality evolved". Here 'morality'
refers, as noted earlier, to a certain *set of empirical
phenomena*, such as the observed capacity of human beings to make
normative judgments, or the tendency to have certain sentiments such
as sympathy or guilt or blame, or certain 'intuitions'
about fairness or violence. Just as we can inquire into the origins
and functions of other traits, such as human linguistic capacities, we
can inquire into the origins and functions of the various
psychological capacities and tendencies associated with
'morality'.



The sense of 'morality' in the above questions may be
called the *empirical sense* of the term, and it is in this
sense that scientists speak of "the evolution of
morality," using such tools as comparative genomics and primate
studies to shed light on it (Rosenberg 2006; de Waal 1996 and 2006).
Such explanatory projects will be discussed in section 2.


2. The Normative Sense of 'Morality'



In contrast to the above, there is a very different use of the term
'morality' in what may be called the *normative*
*sense*. Consider the question: "Does morality require
that we make substantial sacrifices to help distant strangers?"
Such a question arises from the deliberative standpoint as we seek to
determine how we ought to live, and it is a normative rather than an
empirical question. We are not here asking an anthropological question
about some actual moral code--even that of our own
society--but a normative question that might lead us to a new
moral code. When we use 'morality' in the normative sense,
it is meant to refer to *however it is we ought to live*, i.e.,
to *a set of norms that ought to be adopted and
 followed*.[2]



Philosophers employ this normative sense of 'morality' or
'moral' in posing a variety of both normative and
metaethical questions: What does morality require of us? Does morality
have a purely consequentialist structure, as utilitarians claim? What
kind of meaning do claims about morality in the normative sense have?
Are there moral truths--i.e., truths about morality in the
normative sense--and if so, what are they grounded in and how can
we come to know them? Is morality culturally relative or at least
partly universal? (Note that this is not the same as the
*anthropological* question whether or to what extent morality
in the *empirical* sense *varies* from culture to
culture.)



While morality in the normative sense is not an empirical phenomenon
to be explained, there are still important questions to ask about how
evolutionary theory may bear on it. Can we look to our evolutionary
background for moral guidance, gaining insight into the content of
morality in the normative sense (as claimed by proponents of
*prescriptive* evolutionary ethics)? (Section 3) Does
evolutionary theory shed light on metaethics, helping to resolve
questions about the *existence* and *nature* of morality
in the normative sense (as claimed by proponents of evolutionary
metaethics)? Does it, for example, lend support to nihilism (the idea
that there is really *no such thing* *as* *morality
in the normative sense*) or to skepticism (the idea that even if
there are truths about morality in the normative sense we cannot know
them, or at least could not know them if they were objective truths)?
(Section 4)



Having distinguished various issues and questions, we may turn now to
consider first the scientific explanatory projects concerning morality
in the *empirical* sense.


## 2. Descriptive Evolutionary Ethics: Explaining Morality in the Empirical Sense



Evolutionary explanations for morality in the empirical sense are
offered at different levels, and this makes for very different
explanatory projects with different implications. Some typical
*explananda* in accounts of "the evolution of
morality" are:


1. The general capacity for normative judgment and guidance, and the
tendency to exercise this capacity in social life;
2. The capacity for certain sentiments and the ability to detect them
in others;
3. The tendency to experience and to be motivated by certain
sentiments in certain types of situation;
4. The tendency to make certain particular kinds of moral judgment or
inference, or to have certain characteristic moral intuitions (i.e., a
'moral sense');
5. The tendency to exhibit certain particular types of behavior in
certain types of situation (as a result of D);
6. The tendency of societies to exhibit certain particular systems of
norms or types of practice (due to D and E).


### 2.1 Levels and Types of Explanation: Some Possibilities



It is uncontroversial that there will be evolutionary explanations of
*some* sort for the very general capacities and tendencies in A
and B: we are evolved creatures, and our psychological capacities,
like other complex capacities, are outcomes of evolutionary processes.
But this does not by itself settle whether these capacities and
tendencies are themselves *adaptations*, having evolved through
natural selection because of their adaptive effects. That is the most
common view (further explored below), but there are alternatives.



It is possible, for example, that our capacity to make moral judgments
is a spin-off (side-effect or by-product) of our non-moral
intellectual capacities, which latter are
 adaptations.[3]
 On this view, we tend to make moral judgments because we are
intellectual and reflective creatures, not because natural selection
has specifically given us this moral capacity and tendency as an
adaptation; the role of natural selection would be indirect, supplying
more general capacities as adaptations, from which specifically moral
tendencies spring independently (Ayala 2006; Prinz 2008, Machery and
Mallon 2010).



The deeper point, however, is that *whichever* position one
takes on the role of natural selection in the emergence of generic
capacities for moral judgment, this does not settle how best to
account for other, more specific tendencies, such as C-F. In
particular:


* Even if (1) our capacity and tendency to make moral judgments
*is* an adaptation that evolved through natural selection, it
remains possible that (2) the *content* of particular moral
judgments is derived *autonomously*, i.e., free from causal
shaping by particular elements in our evolutionary background--in
roughly the way that the contents of our beliefs in physics or
philosophy seem to be (see section 2.4 below).
* Alternatively, even if (1\*) our capacity and tendency to make
moral judgments is *not* itself an adaptation, it remains
possible that (2\*) the *content* of particular moral judgments
*is* deeply shaped by evolved emotional dispositions that have
affected the content of moral judgments since human beings began
making them. Such emotional adaptations may thus have influenced
cultural norms throughout history and may continue to influence our
moral judgments, and hence our behavior, today.



And of course there are other possibilities: 1 might be combined with
2\*, or 1\* might be combined with 2, and both 2 and 2\* could also be
weakened to apply only to *some* judgments, while others are
explained in other ways, as suggested earlier. There are, then, many
possible stories to be told about the origins of our moral judgments
and behavior.



Since our concern is with *morality*, the crucial issue to
begin with is the origins of *moral judgment*: for morality has
not merely to do with certain emotions and behaviors (such as sympathy
and altruism) as such, but with the exercise of moral
*judgment* about how one ought to behave in various social
circumstances (Joyce 2006, ch. 2; Korsgaard 2006; Kitcher 2006c, 2011;
Machery and Mallon 2010). Certain emotions and behaviors are then
relevant too insofar as they relate to the exercise of such judgment,
but in the absence of moral judgment they seem only to belong to
proto-morality.



Still, many discussions employ a looser notion of
'morality' that refers simply to certain kinds of socially
positive emotion or behavior, such as *psychological altruism*
(defined below). Since accounts of the origins of moral judgment rely
on these ideas as well, and these emotions or behavioral dispositions
are also often appealed to as causal influences on the content of
moral judgment, it is worth starting with a look at the issue of
psychological altruism, distinguishing it from merely biological
altruism.


### 2.2 Biological and Psychological Altruism



Many discussions of morality and evolutionary biology focus largely on
the issue of *altruistic* feeling and behavior. This can be
confusing because in addition to *psychological altruism* there
is also *biological altruism*, which is found in many species.
(See Kitcher 2011, part I, for a comprehensive discussion.)
Psychological altruism involves *caring about others' welfare
and deliberately* *benefiting them for their own sake*,
with no restriction on the type of benefit involved. By contrast,
biological altruism has nothing essentially to do with intentions or
motives, and it pertains only to 'benefits' to others that
increase their *reproductive fitness* (boosting their genetic
contribution to future generations).



Though psychological altruism is different from biological altruism,
there are a variety of possible explanations of the evolution of
psychological altruism that appeal to the same factors that explain
the origins of biological altruism, namely:


* *Kin selection* or 'inclusive fitness' theory
(Hamilton 1964);
* Selection pressures leading to *teamwork*, *reciprocal
altruism* (Trivers 1971; Maynard Smith 1982; Axelrod 1984) and
*indirect reciprocity* (Alexander 1987; Joyce 2006); and
* *Group selection* (Sober and Wilson 1998).



It would take us too far afield to survey all these biological
accounts in detail, the background for which is already treated in the
entry for
 biological altruism;
 there are also many excellent and accessible summaries of such
accounts and their application to psychological altruism (e.g., Joyce
2006, ch. 1). We will settle here for one detailed illustration of one
way in which *biological* altruism can be given an evolutionary
explanation, followed by a sketch of the ways in which this and other
evolutionary mechanisms might likewise explain the emergence of
*psychological* altruism--keeping in mind that this is all
just one part of explaining *morality* proper, to which we
return in the next sub-section.



The very idea that biological altruism can come about through natural
selection may initially seem puzzling. One way of characterizing
natural selection, after all, is in terms of "selfish
genes": natural selection occurs when a variant of a gene (an
allele) at a given locus tends to cause a modification of a bodily or
behavioral trait (a phenotypic trait) in a way that, in the overall
environment, tends to cause that variant of the gene to increase its
relative frequency in the next generation; this then increases the
representation of the associated trait modification as well. Typically
this happens when the phenotypic modification is one that causes the
organism to have greater reproductive success: if, in the overall
context, allele A causes its carrier to have a trait T that causes the
organism to have more offspring than other organisms in the population
who carry rival allele A\* and display alternative trait T\*, then A
will be inherited and carried by more organisms in succeeding
generations; and that means that T will likewise be displayed by more
organisms (Dawkins, 1989). But how do we get from "selfish
genes" increasing their representation in the gene pool, via
improving the reproductive success of their carriers, to such things
as cooperation and biological altruism? It turns out there are many
ways.



To take one dramatic example, consider social insect colonies, and in
particular, the Hymenoptera (bees, ants and wasps). In these colonies
we find such an extreme degree of cooperation--division of labor
(queen, workers, soldiers, etc.), food-sharing, information
sharing--that it is tempting to view the entire colony as a
single functioning organism. Indeed, in the case of stinging worker
honey bees, there is not only cooperative labor but also, when
necessary, the ultimate sacrifice in defense of the hive (at least
where the invader is a mammal, stinging of which proves fatal to the
bee as the barbed sting is torn out upon being deposited in the
victim). How can such striking cooperation and self-sacrifice be
explained in evolutionary terms?



One important fact to notice is that the colony is one large family:
typically, the workers are sisters--daughters of the queen.
Return to the idea of "selfish genes" described above:
what ultimately increases an allele's representation in the gene
pool is its having some phenotypic effect that causes copies of that
allele to be in more organisms in succeeding generations. That
normally happens when the phenotypic effect causes the organism to
have greater reproductive success, but it can equally happen if it
causes the organism's close kin to have greater reproductive
success: for close kin are likely to carry copies of that same allele,
which means that greater reproductive success for kin likewise
propagates copies of the allele. So while an allele that causes an
organism to engage in sex more often may thereby spread, so might an
allele that causes an organism to help a sibling to reproduce (as by
aiding survival); either way, that allele will be helping to propagate
copies of itself in the next generation, which in turn means that the
helping behavior it causes will likewise spread over time (Dawkins
1989, 171-77).



This mechanism of "kin selection" can explain how worker
bees evolved such apparently 'selfless' traits, focused on
aiding the queen's survival and reproduction. In fact, the
situation is even more interesting and extreme: workers have evolved
to serve the queen's reproduction at the complete expense of their
own, as they are *sterile*. This extreme biological altruism,
however, may be explained by the same principles, with the addition of
the fact that due to a genetic peculiarity of the Hymenoptera (their
haplodiploidy), sisters are *more* closely related to each
other genetically than they would be to their own
 offspring.[4]
 This means that natural selection will actually favor worker traits
that help their *mother* reproduce (thus making more sisters,
who are especially likely to carry copies of the gene for that same
trait, making it spread), over traits in workers aimed at personal
reproduction. This could explain how worker sterility evolved, as
traits focused on helping the queen took precedence over personal
reproduction, and it explains how even suicidal behavior could have
been selected for as propagating the genes that cause it (Dawkins
1989, 174-75). (It is worth noting, however, that the theory of
kin selection and inclusive fitness is highly complex and has received
renewed critical scrutiny in recent years. For a recent special
collection of articles on the topic see
 Royal Society Open Science on Inclusive Fitness).



This is only one example of one way in which biological altruism can
evolve: there are others, which are not restricted to kin and are
explained using game-theoretic or group dynamic models (again, see the
entry on
 biological altruism
 for details). The crucial point is just that *any* kind of
genetically-based trait can evolve if it happens to have the right
kind of feedback effect on the genes that influence it. This brings
us, then, to the sort of trait we are more interested in: a
*disposition for psychological altruism*, as defined above.



Again, while it may initially seem puzzling that evolution should give
rise to psychological altruism, rather than merely to selfishness,
there is nothing paradoxical about it: a genetically-based disposition
for psychological altruism will evolve just in case such a trait, in
the relevant circumstances, promotes the propagation of the genes that
bring it about (and does so more effectively than alternative traits
produced by rival alleles). And this can again happen in various
ways.



The basic idea is that psychological altruistic dispositions can
evolve as *proximate mechanisms* or "modules" for
promoting the biological advantages relevant to the forms of selection
listed above. In some cases, these adaptive psychological mechanisms
will involve specifically targeted or conditional altruistic
motivations, involving capacities for discrimination to focus benefits
on kin or on reciprocators. In other cases, the selection pressures
will give rise to less discriminating altruistic sentiments and
tendencies as the simplest and most cost-effective mechanisms for
promoting adaptive cooperative behaviors in a given environment. If
our hominin ancestors tended to live in circumstances where the
opportunities for 'wasting' altruism in
non-fitness-enhancing ways (e.g., on 'outsiders') were
sufficiently few and far between, then a simple, undiscriminating
(though limited) sense of concern and altruism may have promoted
fitness at far less cost than more discriminating forms, evolving more
readily. One advantage of this hypothesis is that it might help
explain some sorts of concern and altruism that are otherwise hard to
make sense of in evolutionary terms.



For example, suppose you receive a letter from UNICEF soliciting
contributions for health and nutrition programs for children in
Darfur, and you are moved to send a check. This is not merely
selective altruism toward kin or likely reciprocators, but altruism
toward strangers who are in no position to reciprocate, and it might
therefore seem puzzling from a purely biological point of view: such
'indiscriminate altruism' isn't biologically adaptive
in the way more selective altruism might be; your helping children in
Darfur isn't helping to propagate your own genes, so it may seem
mysterious how such a trait could have evolved through natural
selection. But a trait that is not presently adaptive may once have
been. In the environment in which our hominin ancestors lived, where
there was little positive contact with outsiders, even relatively
indiscriminate altruism would tend to benefit kin or potential
reciprocators, and so might have been a simple adaptive mechanism on
the whole.



If so, then your presently non-adaptive altruistic behavior in our
current global environment could in principle be an expression of an
evolved, indiscriminate altruistic tendency--an adaptation that
is largely no longer adaptive, and so would amount to a kind of
'misfiring' of formerly adaptive instincts (Dawkins 2006,
220-21; Kitcher 2006b). It would be in this way on a par with
our taste for fatty foods--originally evolved for its adaptive
effects though it is no longer beneficial in today's fast food
economy--though in the case of altruism the
'misfiring' has happier results. Of course, it's also
possible (as discussed in section 2.4) that your altruistic tendency
isn't itself an adaptation at all, but is instead rooted in values
that you've developed, through moral reflection in your cultural
context, independently of specific evolutionary influences. Or it may
be some combination of the two.



This area of inquiry remains largely speculative, since it is one
thing to develop models for how psychological altruism could in
principle evolve, and quite another to show convincingly that a given
form of natural selection has in fact played the relevant role in
actual human evolutionary history. There may be doubts, for example,
whether there was sufficient pair-wise engagement in iterated
prisoner's dilemma games to explain the evolution of reciprocal
altruism according to some of the most familiar game-theoretic models
(Kitcher 2006a,b). In any case, it is time to return to the issue of
moral judgment, which is crucial to the explanation of
*morality* proper, and goes beyond mere altruistic feeling and
behavior. The following sub-section describes one leading
hypothesis.


### 2.3 Explaining the Origins of Morality: From Psychological Altruism to the Evolution of Normative Guidance



Kitcher (2006a,b; 2011) has proposed a three-stage account of the
evolution of morality. It begins with the evolution of an early but
fragile form of psychological altruism among hominins in the context
of "coalition games" in mixed adult groups. The social
structure would have been similar to that of contemporary chimpanzees
and bonobos, where cooperation among the relatively weak (or those in
weak stages of life) is beneficial to them, but strategic calculation
is infeasible. These conditions may have led from simpler forms of
biological altruism developed through kin selection to the evolution
of a psychological altruistic disposition involving "a blind
tendency to respond to the preferences of another animal with whom you
might engage in cooperative activity," as a simple but effective
mechanism for promoting advantageous participation in coalitions and
subcoalitions (Kitcher 2006b). (This is the
'indiscriminate' altruism discussed in the previous
sub-section.)



Because this disposition was both limited and unstable, however, and
competed with powerful selfish drives, there was a continual threat of
social rupture and loss of cooperative advantage. This in turn would
have made ongoing peacemaking a necessity, thus limiting the size of
viable cooperative units and the scope of cooperative projects, as
well as imposing significant costs through the devotion of time and
energy to peacemaking activities. An example would be extensive mutual
grooming going well beyond what is necessary for hygiene, of the sort
found in chimpanzee societies.



The next phase, according to this hypothesis, was a transition to much
larger groups with more extensive cooperative activities, through the
evolution of a *capacity for emotionally laden* *normative
guidance*, without which such arrangements would not have been
possible. (See also Gibbard 1990, ch. 4.) With the emergence of a
capacity to make and follow normative judgments, reinforced by
coevolved reactive emotions such as guilt and resentment, and the
development of rules and social practices promoting and enforcing
group loyalty and cooperation, a new psychological mechanism came into
being for reinforcing the previously unstable altruistic tendencies
and promoting large-scale social cohesion and stability. The
advantages of membership in coalitions and subcoalitions would be
conferred on hominins who had facility with such normative
guidance--including a strong sense of obligation and tendency
toward social compliance--and who thus acted consistently on
these altruistic tendencies, acquiring the reputation for being good
coalition partners and participating in a broader array of cooperative
projects.



If this hypothesis is correct, it might explain not only the origins
of our general capacity for normative judgment and motivation, but
also the widespread tendency for social rules or norms historically to
emphasize such things as *group identity, loyalty and
cohesion*, and to focus largely on the regulation of
*violence* and *sex*; and it might help to explain
widespread dispositions toward *social conformity, concern with
reputation and social standing, tendencies for group-wise scorning or
punishment of the disloyal, and the power of emotions such as
resentment, guilt and shame*.



In the final phase, this sort of "proto-morality" of norms
and reactive emotions would then be supplemented over thousands of
years with various paths of
 *cultural evolution*,
 leading to the development and fleshing out of the much more
sophisticated systems of moral beliefs, practices and institutions
with which we are familiar, from the earliest historical examples
right up to our present moral cultures (Kitcher 2006a, 2011). There
is, of course, a great deal of leeway in the last part, concerning the
details of the transition through cultural evolution from hominin
proto-moralities to contemporary moral systems, which allows for some
very different possible stories. Some accounts will attribute great
influence to evolved, "domain-specific psychological
modules" (such as a dedicated mechanism that automatically
generates a feeling of concern when confronted with suffering) in
shaping the content of our moral feeling, judgment and behavior, both
through shaping our cultures and more directly; other accounts, while
not denying some such influence, will emphasize very different factors
as influencing the content of at least some of our moral beliefs (such
as the "capacity for open-ended normativity" cited by
Buchanan and Powell 2015, 2018, 2019). This brings us to the next
major topic.


### 2.4 Autonomous Moral Reflection and the Explanation of Reasoned Moral Judgment and Behavior



So far, we have focused on scientific projects that treat morality in
the empirical sense as calling simply for causal explanation, as by
appeal to evolutionary influences. This is unexceptionable with regard
to the origins of the general human capacity for moral judgment:
clearly some causal explanation is required, and an evolutionary
explanation is plausible. But things are much more complicated when we
consider the explanation of the actual *content* of moral
judgment, feeling and behavior.



We have had a taste above of the way in which scientists might propose
to explain our particular moral attitudes or judgments by appeal to
specific evolutionary causes as filtered through cultural
developments. Human beings have a strong, emotionally-laden sense of
basic fairness, resentment of cheaters, and a desire that they be
punished, all of which finds expression in both cultural norms and
individual moral judgments. You might experience such feelings if
you've been the victim of a scam, morally condemning the
perpetrators. And some of these psychological traits may have
analogues in other species. For example, Sarah Brosnan and Frans de
Waal (2014) argue that "evidence indicates that [*inequity
aversion*, i.e., negative reactions to unequal
rewards for similar tasks] is widespread in cooperative species
under many circumstances"--though some have disputed this and
offered alternative hypotheses to explain the behavior, based on
further research (Engelmann, Clift, Herrmann, and Tomasello
2017).[5]
In the simplest case, an animal
protests when it sees a companion receive a superior reward for a
similar task, as in a well-known study with brown capuchin monkeys,
though similar effects have now been observed even in non-primates,
such as dogs and crows. In the more complex
case, chimpanzees sometimes react negatively to inequity even
where they are the ones receiving the greater reward. A natural
evolutionary hypothesis for the simpler case is that such a
disposition protected against 'wasting' cooperative
efforts where they were not fitness-enhancing. Similarly, a natural
explanatory hypothesis for the more complex form of inequity
aversion is that it evolved in creatures with sufficient
predictive capacities and emotional control because it
preserved beneficial cooperative relationships that could be
threatened by such inequities, thus proving fitness-enhancing on the
whole given the benefits of continued cooperation (Brosnan and de
Waal, 2014). All of this might suggest good prospects for causal
explanation of human moral traits in terms of evolved psychological
traits. Indeed, Brosnan and de Waal explicitly hypothesize that the
evolved complex response observed in champanzees is what
"allowed the development of a complete sense of fairness in
humans, which aims not at equality for its own sake but for the sake
of continued cooperation" (Brosnan and de Waal, 2014).



Caution is needed here, however. Our moral judgments and resulting
behaviors cannot just be assumed to be *mere causal upshots* of
some such biological and psychological forces, on a par with the
cooperative activity of bees or the resentment felt by capuchin
monkeys (or even the broader unease apparently felt by chimpanzees)
over unequal rewards for equal work. When a rational agent makes a
judgment, whether in the sphere of morality or in such areas as
science, mathematics or philosophy, the proper question is not in the
first instance what *caused* that judgment to occur, but what
*reasons* the person had for making it--for thinking it to
be true. It is those reasons that typically constitute an explanation
of the judgment. They explain by bringing out what the person
*took* (rightly or wrongly) to be the *justification*
for the belief in question--the considerations showing the belief
likely to be true. All of this complicates the explanatory project in
relation to the thoughts, feelings and actions of rational agents.



It is helpful to illustrate the general point first with other kinds
of judgment, and then to return to morality. Consider some judgments
in mathematics, philosophy and science:



> 
> 
> M: There is at least one prime number between 5,000 and 10,000.
> 
> 
> 
> P: If identity claims such as 'water = H2O' are
> true, then they are *necessary truths* (i.e., true in all
> possible worlds).
> 
> 
> 
> S: There is no such thing as absolute simultaneity.
> 
> 
> 



How do we explain someone's believing something like M, P or S? We
normally need to know *her reasons* for believing it to be
true, which we can then go on to assess as good or bad reasons for
such a belief. Either way, we typically take her reasons--and the
*reasoning* associated with them--to explain her belief,
which is why we engage seriously with her reasons as such in critical
discussion, and go on to inquire into their merits. If, for example,
we ask a person why she believes M, and she cites a proof she has
found convincing, showing that for any natural number *n* >
1 there is at least one prime number between *n* and
2*n*, we normally take this as a sufficient explanation for why
she believes M. What we do *not* normally do is to appeal
directly to independent causes, such as evolutionary or other
biological or psychological influences to explain people's beliefs
in these areas. Such independent explanations for beliefs can
sometimes be correct, as in the case of someone given a post-hypnotic
suggestion, in which case we may regard her judgment as *merely
caused* and the reasons offered as mere rationalization. But this
is not the norm.



The reason why we normally explain beliefs such as M, P or S by appeal
to the reasons the person gives for them is that we normally assume
that the person is capable of intelligent reflection and reasoning and
has arrived at her belief for the reasons she gives as a result of
that reflection (whether or not the belief is ultimately correct). We
assume in general that people are capable of significant
*autonomy* in their thinking, in the following sense:



> 
> *Autonomy Assumption*: people have, to greater or lesser
> degrees, a capacity for reasoning that follows *autonomous
> standards appropriate to the subjects in question*, rather than in
> slavish service to evolutionarily given instincts merely filtered
> through cultural forms or applied in novel environments. Such
> reflection, reasoning, judgment and resulting behavior seem to be
> *autonomous* in the sense that they involve *exercises of
> thought that are not themselves significantly shaped by specific
> evolutionarily given tendencies, but instead follow independent norms
> appropriate to the pursuits in question* (Nagel 1979).
> 



This assumption seems hard to deny in the face of such abstract
pursuits as algebraic topology, quantum field theory, population
biology, modal metaphysics, or twelve-tone musical composition, all of
which seem transparently to involve precisely such *autonomous
applications of human intelligence*. Even if there are
evolutionary influences behind our general tendency to engage in
certain kinds of mental activity, or behind some of our motives in
these pursuits (e.g., if a given musician or poet is motivated to
compose music or poetry in order to impress a potential mate), this
would not show that the activity is governed in its details by such
influences (cf. Buchanan and Powell 2015, 2018, and 2019). And again,
this assumption of autonomy is borne out in our normal explanations of
beliefs such as P above: we take a person at her word that what
explains her believing P, for example, is that due to philosophical
arguments she's read and has found convincing she takes
'water' to work like a proper name and thinks that it
follows from this that 'water' refers to whatever
molecular compound it picks out in the actual world in all possible
worlds in which the compound exists.



Few would deny the autonomy assumption altogether. To do so in the
name of providing alternative evolutionary causal explanations of our
beliefs would risk self-defeat: for if we lack the relevant
intellectual autonomy across the board, then even *the
biologist's beliefs about evolutionary biology and its
implications* would just be attributable to such biological
causes, rather than to reasons that provide real warrant for such
beliefs within a rational framework with truth-tracking integrity. The
challenge to the autonomy assumption is therefore more likely to come
in a selective
 form.[6]



This brings us back to moral judgment. As with M, P and S, people
typically have *reasons* for their moral judgments, and whether
or not we agree with them, we typically take those reasons to explain
why they believe what they do. Consider again the moral judgment
mentioned earlier:



> 
> MJ: The person who cheated me did something wrong and should be
> punished.
> 



Just as with M, P and S, someone making this judgment will have
reasons that she takes to justify this claim, ultimately tying into
her overall conception of right and wrong. And we tend to take this at
face value as an explanation of why she believes MJ, unless we have
special reason to suspect distorting causes, such as prejudice leading
to misperception and rationalization. We tend to think that a person
has the moral beliefs she does as a result of background moral
reflection and reasoning, within her cultural context. In other words,
we tend to treat a person's moral beliefs much as we treat her
reasoned mathematical, scientific, or philosophical beliefs, applying
the autonomy assumption in seeking to explain why she believes what
she does.



One potential lesson from evolutionary biology, however, is that even
if the autonomy assumption equally applies *in principle* to
the sphere of moral judgment, it may be a mistake just to assume that
most moral judgment and behavior is in fact a result of the exercise
of such autonomous reflection, reasoning and judgment. The autonomy
assumption, after all, says only that we have the capacity for
relevantly autonomous reflection and judgment; it does not imply that
we always exercise it. Perhaps the human capacity for autonomous
thinking is exercised only in some cases, while in others the process
that leads to moral belief is largely influenced by evolved
psychological dispositions, such as emotional adaptations. While such
a situation may not tend to arise in relation to our mathematical,
philosophical, or scientific thinking, our evolutionary history may
have given rise to emotional dispositions that play a significant role
in at least some of our moral thinking, feeling and behavior. (See
section 2.5 below.)



One plausible story, then, is that while many of our more reflective
and reasoned moral judgments involve autonomous exercises of
domain-general intelligence, many other less reflective moral
judgments are largely attributable to evolutionary
influences--both through direct conditioning of people's
moral judgments by evolved, domain-specific psychological dispositions
and through background influences on cultural factors. On this
hypothesis, we cannot treat moral judgments as a homogeneous set, but
must recognize that they can come about in very different ways,
requiring a plurality of explanatory models. While a model of
autonomous reasoning might apply to some moral beliefs and behaviors,
a model appealing to evolutionary causal influences will apply to
others. And often some combination of models may be necessary, as in
cases where both evolutionary influences and our own independent moral
reflection might lead to similar judgments, *overdetermining*
them.



For example, even if it is true that evolutionary pressures favoring
caring for offspring have strongly influenced our attitudes towards
our children, it does not follow that this is the complete explanation
for why we believe we have special obligations to care for our
children and for why we behave as we do toward them. It may be
*part* of the explanation, while another part may have to do
with an autonomous recognition of the *appropriateness* of
special parental care: we see that we have *good reasons* to
take special care of our children, which *ought* to motivate us
even if we weren't already motivated by instinctive feelings. We
might also employ autonomous, domain-general comprehensive moral
reasoning to recognize that our instinctive feelings shouldn't
always be followed, e.g., in cases where considerations of justice
constrain certain pursuits of benefits for one's own children,
providing genuine overriding reasons to refrain from unjust actions.
(We will consider another plausible example of overdetermination
involving judgments about the much discussed 'Trolley
cases' in section 3.)


### 2.5 The Challenge to the Autonomous Reflection Model: *Post Hoc* Rationalization of Emotionally Caused Judgment



Advocates of an autonomous reflection model of moral judgment grant
that various causal influences--likely including evolutionary
ones--often play *some* role in moral thought and feeling.
But opponents who hold a deflationary view of the role of autonomous
reflection seek to press the challenge here more fully. To expand the
potential reach of the evolutionary influence model of moral judgment,
they typically combine that causal model with what may be called the
'mere rationalization hypothesis' with regard to the
*reasons* people give for moral judgments that are really
shaped by evolutionary factors.



On this view, our giving of *reasons* for our moral beliefs in
such cases is interpreted as mere *post hoc rationalization*.
Rather than engaging in autonomous reflection and reasoning, and
coming to believe certain moral propositions for the reasons that
emerge from that reflection (as with M, P and S), what is happening
instead according to this hypothesis is that (1) our moral beliefs are
simply *caused* by *emotions* or 'moral
instincts' we have largely due to our evolutionary background,
and (2) we then invent *rationalizations* for these resulting
beliefs in order to try to make sense of them to ourselves, unaware of
their real causal origins (Haidt 2001; Wheatley and Haidt 2005; Knobe
and Leiter 2007; Leiter 2007).



For example, when someone judges that abortion is wrong, it may be
that "the anti-abortion judgment (a gut feeling that abortion is
bad) causes the belief that life begins at conception (an *ex post
facto* rationalization of the gut feeling)" (Haidt 2001,
817). On this model, our moral reasonings and justifications (or at
least those to which the model is supposed to apply) are just so much
window dressing for beliefs that are more like post-hypnotic
suggestions than they are like M, P or S; just as with post-hypnotic
suggestions, people go to great lengths to provide rationalizations in
an attempt to render their moral beliefs intelligible to themselves.
The difference is that instead of a hypnotist, the causal agents are
emotional dispositions stemming from our evolutionary past.



The basic idea that *some* moral beliefs are susceptible to
this sort of debunking explanation is not new. Moral philosophers have
long recognized that people have often been led to moral judgments
based on self-interest or prejudice, for example, and then
rationalized their views, inventing justifications for positions held
due to other causes. A plausible example would be a judgment such
as:



> 
> MJ2: Interracial marriage is morally wrong.
> 



While such a judgment was not uncommon just a few generations ago,
most readers of this article will recognize MJ2 to be not only false,
but also likely to have stemmed from racial prejudice, with much of
what was said to justify it being mere *post hoc*
rationalization for a view more attributable to the causal influence
of prejudice than to the workings of autonomous reflection and
reasononing. Most philosophers today would say something similar about
a moral belief still held by many people, especially within
traditional religions:



> 
> MJ3: Homosexuality is morally wrong.
> 



The reason why philosophers tend to find a 'mere rationalization
hypothesis' plausible for such beliefs as MJ2 and MJ3 is that
(i) the justifications offered for them have consistently failed to
stand up to critical reflection, and (ii) there are plausible
alternative explanations for why people have really come to hold such
beliefs, such as that they have misconstrued personal feelings of
disgust as perceptions of objective moral wrongness, and projected
those feelings onto the world as 'moral
 impurity'.[7]
 Together, these considerations lend support to the hypothesis that
the justifications offered are mere rationalizations, and that the
beliefs are best explained by appeal to emotional causes.



The central question is: How broadly does the deflationary model of
the 'mere rationalization hypothesis' apply to moral
judgments, and to what extent are evolutionary influences implicated
in those cases?



At one extreme, someone might deny that the autonomy assumption
applies to the moral domain at all: we either lack these capacities in
the domain of moral thought, or at least never exercise them. Such a
claim seems to have little plausibility, however. Why should it be
that human intelligence and innovation know virtually no bounds in
other domains--as illustrated by feats of autonomous inquiry and
creativity in quantum field theory, algebraic topology, modal
metaphysics, or symphonic composition--and yet when it comes to
moral thinking we remain stuck in ruts carved out for us by evolution,
slavishly following patterns of thought prescribed for us by evolved,
domain-specific mechanisms, with all of our cultural developments
providing mere variations on those themes?



The very fact of human self-consciousness makes such a picture
unlikely: for as soon as we are told that our thinking is constrained
along evolutionarily given paths, our very awareness of those
influences provides the opening to imagine and to pursue new
possibilities. If you are told, for example, that you are
evolutionarily conditioned to favor your group heavily over outsiders
in your moral judgments, you are able, as a reflective agent, to take
this very fact into account in your subsequent moral reflection,
deciding that this favoring is unwarranted and thus coming to a new,
more egalitarian moral
 view.[8]
 Analogously, it may be true that we possess dedicated mechanisms for
'reading' faces as trustworthy or threatening, and often
make split-second judgments on this basis; but this doesn't
preclude our ability to revise such judgments, as when we reflect on
the behavior of someone with 'trustworthy facial features'
and realize that he is actually a scoundrel.



It is noteworthy that the leading proponent of the mere
rationalization hypothesis, Jonathan Haidt (2001), does *not*
take the extreme position of denying the autonomy assumption. He
grants that such capacities exist and are sometimes exercised,
singling out the moral deliberations of philosophers as likely
examples (2001, 828-29). His claim is just that such exercise of
autonomous reasoning in the production of moral judgment is rare; in
the vast majority of cases, our judgments result from immediate
'intuitions' reflecting emotional causation. But there are
many questions to raise even about this qualified claim (despite its
generously letting philosophers, at least, off the hook).



Even where our judgments are based on immediate
'intuitions', it may be that these intuitions are often
themselves *informed* by *prior* acts of reflection and
reasoning (Pizarro and Bloom 2003), or are partly cognitive responses
to objective features of situations that may outrun our ability (prior
to philosophical reflection) to articulate them--much as a chess
master may 'see' that a certain move is best prior to
being able to articulate exactly why (Kamm 1996, 2007). Similarly, the
input from the autonomous reasoning of philosophers and some religious
leaders may well influence the background ethical sensibilities of
whole societies, thus influencing moral judgment even where there is
no lengthy reasoning occurring in the particular case. There are also
important philosophical worries about the methodologies by which Haidt
comes to his deflationary conclusions about the role played by
reasoning in ordinary people's moral judgments.



To take just one example, Haidt cites a study where people made
negative moral judgments in response to "actions that were
offensive yet harmless, such as...cleaning one's toilet with
the national flag." People had negative emotional reactions to
these things and judged them to be wrong, despite the fact that they
did not cause any harms to anyone; that is, "affective reactions
were good predictors of judgment, whereas perceptions of harmfulness
were not" (Haidt 2001, 817). He takes this to support the
conclusion that people's moral judgments in these cases are based
on gut feelings and merely rationalized, since the actions, being
harmless, don't actually warrant such negative moral judgments.
But such a conclusion would be supported only if all the subjects in
the experiment were *consequentialists*, specifically believing
that *only harmful consequences* are relevant to moral
wrongness. If they are not, and believe--perhaps quite rightly
(though it doesn't matter for the present point what the truth is
here)--that there are *other* factors that can make an
action wrong, then their judgments may be perfectly appropriate
despite the lack of harmful consequences.



This is in fact entirely plausible in the cases studied: most people
think that it is inherently *disrespectful*, and hence wrong,
to clean a toilet with their nation's flag, quite apart from the
fact that it doesn't hurt anyone; so the fact that their moral
judgment lines up with their emotions but not with a belief that there
will be harmful consequences does not show (or even suggest) that the
moral judgment is merely caused by emotions or gut reactions. Nor is
it surprising that people have trouble articulating their reasons when
they find an action *intrinsically* inappropriate, as by being
disrespectful (as opposed to being instrumentally bad, which is much
easier to explain).



To return to our central question: it remains unclear just how much of
human moral judgment is susceptible to the mere rationalization
hypothesis, or when it is, how much of a role is played by
evolutionary influences on emotions. The mere rationalization
hypothesis is best supported when we have independent reason to reject
an appeal to autonomous reflection, as when a moral judgment is
implausible in itself and we have a very likely debunking causal
explanation of why someone might nonetheless be led to believe such a
thing. Such is the case with MJ2 and MJ3 above, and perhaps many other
traditional moral judgments focused on *sexual taboos, notions of
'impurity', in-group loyalty (from tribalism to
nationalism), hierarchical authority relations, and rigid gender
roles*. But this does not provide grounds for a deflationary
approach across the board.



Many moral beliefs--for example, concerning the moral irrelevance
of sexual preference, the moral equality of persons of all races and
nationalities, or moral obligations even to future generations in far
away countries--are much more plausible candidates for being
upshots of autonomous moral reflection and reasoning. Indeed, many
philosophers take them to be plausible candidates for moral
*truths*, grasped through reflection that reveals *good
reasons* for believing them, which is therefore what explains our
moral beliefs and behavior in these cases.



These claims may, of course, be disputed. Even if it is granted that
our judgments are often the products of our reasoning, *pace*
Haidt (2001), it remains possible that our reasoning itself is
distorted by evolutionary influences. This may be especially worrisome
given the role played by *intuitions* in moral reasoning
(unlike with mathematical reasoning, say), even in determining our
acceptance of premises in arguments: insofar as there are concerns
that our intuitions may be distorted by evolutionary influences, there
will equally be worries about our moral reasoning (Sinnott-Armstrong
2005).



It remains unclear, however, just how far such worries really extend,
even if it is granted that moral intuition and reasoning are often
subject to such distorting influence. It is hard to see, for example,
how some people's moral belief that we should impoverish ourselves
and limit our own reproduction in order to help distant strangers, or
even that we should cease having children altogether, could be
explained in terms of the distortion of their reasoning by
evolutionary influences. The striking range of moral beliefs itself,
both across and within cultures, seems like good evidence of
significant input from autonomous moral reflection--moral thought
going beyond exercises of evolved "neurocomputational
systems" or "social contract algorithms" or
"inference engines" with domain-specific goals and special
inference procedures designed for solving particular adaptive problems
(Cosmides and Tooby 2008). Even if there are indeed such special
modules devoted to reasoning about obligation and entitlement, as
posited by evolutionary psychologists, the question is how much they
explain, and whether they really exclude significant input from
autonomous moral reasoning.



These issues remain challenging and controversial. But the
controversies are as much ongoing *philosophical* ones as
scientific ones, and it is therefore unlikely that scientific results
will settle them. Science will plainly not settle, for example,
whether or not there are moral truths; and if there are, they will
likely play an explanatory role with regard to at least some of our
moral beliefs--something we will miss if we approach these issues
from an exclusively scientific point of view.



A duly cautious claim about the explanatory role of evolution with
respect to morality in the empirical sense might therefore be:



> 
> *The Modest Evolutionary Explanatory Thesis*: evolutionary
> forces may adequately explain certain *capacities* and
> *tendencies* associated with moral thinking, feeling and
> behavior, and may explain or *partially* explain *some*
> of the *content* of our moral thought, feeling and behavior,
> insofar as it is influenced (individually or via influences on
> cultural development) by those tendencies.
> 


## 3. Evolutionary Biology and Normative Ethics: Prescriptive Evolutionary Ethics, Corrective Evolutionary Ethics, and the Question of Moral Progress



In section 1.2, we distinguished between the empirical and normative
senses of 'morality'. This section deals with *morality
in the normative sense*. Does evolutionary biology shed light on
the content of morality in the normative sense? That is, in thinking
about how we ought to live, do we get any insight from evolutionary
theory? And does evolutionary biology have any significant
implications for thinking about the prospects for moral progress?


### 3.1 Spencer



The project of attempting to derive normative conclusions from the
facts of evolutionary biology is most commonly associated with Herbert
Spencer and his "Social Darwinist" admirers. Spencer was,
by all accounts, a more gifted and subtle thinker than he is typically
given credit for today. (See the entry on
 Spencer.)
 Still, we may treat his views briefly here, as his arguments
concerning evolutionary biology and ethics were based on deep
misunderstandings of evolution. This is not to deny the historical
interest of his views. It may be surprising to learn, for example,
that Spencer himself gave a central place to harmony and *mutual
aid* in the "permanently peaceful societies" he viewed
as the pinnacle of evolution in its "highest
phase"--something one does not typically associate with
"Social Darwinism", but which comes directly from
Spencer's (largely non-Darwinian) conception of evolution.



Spencer (1879) conceived of evolution as a teleological process,
directed toward the production of progressively "more
evolved" (in the sense of "superior") forms
manifesting a greater "totality of life", i.e., a greater
richness of thought, feeling and action, as well as greater length of
life. Human behavior is "more evolved" than the behavior
of other animals, and the harmonious and mutually supportive behavior
of people in "permanently peaceful societies" (where
"self-maintenance and race-maintenance" is pursued without
hindering others in the same pursuit) is "more evolved"
than the behavior of savages or of members of less harmonious
societies; that is, the former is the "highest form of
conduct" because it subserves the greatest "totality of
life" embodied by harmonious and happy human social life, where
the latter is taken to be the final end of evolution.



All of this, of course, is inconsistent with Darwinism, which denies
that evolution is a teleological or end-directed process, gives no
meaning to Spencer's notions of "more evolved" forms
or conduct (whereby human beings, for example, are "more
evolved" than other species, or ethical conduct is "more
evolved" than unethical conduct), and focuses on reproductive
fitness rather than on Spencer's notion of the "greatest
totality of life in self, in offspring and in fellow man," among
other fundamental differences (Rachels 1990). Spencer's views on
morality and evolution may therefore be set aside as historically
interesting but unhelpful to contemporary discussions based on a
better understanding of evolutionary biology.


### 3.2 Biology and the Autonomy of Ethics



Even philosophers sympathetic to
 ethical naturalism
 (the view that moral facts are themselves natural facts of some sort)
have typically been wary of attempts to derive conclusions about
morality in the *normative* sense from facts about evolutionary
history. This is especially so when they are clear (unlike Spencer)
about the principles governing Darwinian evolution through natural
selection. From the fact that a certain trait is an adaptation, which
evolved through natural selection by virtue of its positive feedback
effects on germ-line replication of the alleles that generate the
trait, nothing at all seems to follow about whether it is morally good
or right, or something we ought to embrace and foster. Certain
dispositions may be present in us for good evolutionary reasons
without any implication that these traits benefit us, or are moral
virtues or produce behaviors that are morally right.



A brief survey of some of the traits that are likely biological
adaptations in a number of species--such as a tendency to kill
'step-children' or to philander--ought to convince us
that even if similar tendencies are likewise adaptations in human
beings, present in us for similar evolutionary reasons, this would be
no argument at all that we *ought* to engage in such behaviors.
Clearly the burden would be on the prescriptive evolutionary ethicist
to explain why a trait's having been good at propagating the
alleles coding for it tens or hundreds of thousands of years ago
should be thought to have anything at all with the *rational or
moral justification* *of our embracing it*. And the
prospects for meeting this burden have never seemed strong: it is hard
to see how such evolutionary facts can possibly have *normative
authority or force* for a rational agent (McDowell 1995).
Regardless of why one has a given trait, the question for a rational
agent is always: is it right for me to exercise it, or should I
instead renounce and resist it as far as I am able? (Korsgaard
 2006).[9]



This suggests that ethics, like mathematics, is an *autonomous*
subject in the sense that it has its own "internal standards of
justification and criticism", such that its conclusions cannot
be justified by other forms of inquiry such as evolutionary biology
(Nagel 1979, 142; McDowell 1995 and 1997a,b). Normative ethical
conclusions are justified through first-order ethical reflection and
argument, just as mathematical propositions are justified through
mathematical reasoning, rather than through learning more about our
evolutionary past or about what is happening in our brains when we
engage in these forms of reasoning (Rachels, 1990). It would seem to
be as much of a mistake to try to answer ethical questions by
examining fMRI scans or studying our evolutionary history as it would
be to try to solve mathematical problems by such means (except,
perhaps, insofar as evolutionary theory may shed light on some
present, morally relevant empirical facts, as discussed below).



Still, some have argued that empirical psychological studies (and
related evolutionary hypotheses--see section 4.2) can have
normative ethical implications. In particular, it has recently been
argued that scientific evidence supports *consequentialist*
ethical theories over deontological ones (Greene 2003, 2008, Singer
2005). Consider a famous pair of hypothetical cases much discussed by
moral philosophers (Thomson 1985):



> 
> 
> *Trolley*: a runaway trolley is heading toward five people on
> the track ahead, who cannot get out of the way; it cannot be stopped,
> but there is a switch you could flip that would divert it onto a side
> track containing only one person;
> 
> 
> 
> *Bridge*: a runaway trolley is heading toward five people on
> the track ahead, who cannot get out of the way; you are standing on a
> bridge over the track, and if you shove the very large person next to
> you off the bridge and in front of the trolley, the crushing of his
> body will stop the trolley before it reaches the five.
> 
> 
> 



Most people respond to these cases by saying that Trolley is
permissible while Bridge is not. But what explains this difference in
moral response? Many philosophers have argued for deontological
constraints prohibiting murdering some to save others, as in Bridge;
they regard the case of diverting a public threat toward lesser harm,
as in Trolley, as an exception, and offer principled reasons for doing
so, thus justifying our treating the two cases differently (e.g.,
Thomson 1985). Greene (2008, 42-44) dismisses such normative
explanations as unconvincing and takes a very different tack,
highlighting another difference between Trolley and Bridge: whereas
the harm done in Bridge (shoving a man to his death) is "up
close and personal", the harm done in Trolley (by flipping a
switch) is not. This difference corresponds to a difference in the
strength of emotional response, the response to "personal"
harm being much stronger; and this in turn corresponds to a difference
in the brain regions most active when the cases are contemplated:
Bridge tends to activate areas associated with social/emotional
processing (the posterior cingulate cortex, the medial prefrontal
cortex, and the amygdala) while Trolley produces activity in areas
associated with higher cognition (the dorsolateral prefrontal cortex
and the inferior parietal lobe).



Greene takes this to support the hypothesis that what accounts for
people's different moral responses to Trolley and Bridge (and
countless other cases) is simply the difference in emotional response,
which in turn ties in to evolutionary explanations. Given the need in
our evolutionary past for mechanisms to restrain interpersonal
violence within cooperating groups, "it should come as no
surprise if we have innate responses to personal violence that are
powerful but rather primitive," predating the evolution of
complex reasoning and now competing with our more reasoned responses
(Greene 2008, 43). Deontological intuitions, such as our condemnation
of the violence in Bridge, thus represent evolved "alarm-like
emotional responses" which are subsequently
*rationalized* rather than resulting from moral reasoning (see
the discussion of Haidt in section 2.5); by contrast, our responses to
more abstract harm such as Trolley reflect complex cognitive
processes, as do consequentialist responses generally, including cases
where people overcome their initial negative emotional responses (in
cases like Bridge) and decide that the right thing to do is whatever
produces the best overall consequences.



Greene's claim, then, is that this casts doubt on deontological
ethical theory: far from giving us good reasons to refrain from
certain utility maximizing acts, it merely gives expression to
emotional relics of our evolutionary history. A rational morality will
move beyond such alarm-like emotions and take us, through genuine
reasoning, in the direction of consequentialism.



As with Haidt's claims about moral judgment (section 2.5), there
are many philosophical questions to raise about such appeals to
experimental data to draw philosophically loaded conclusions (Appiah
2008, Berker 2009, Dancy 2014, Railton 2014, FitzPatrick 2018). It is
hardly surprising, after all, that people have strong emotional
reactions to blatant rights violations such as shoving an innocent
person off a bridge in front of a trolley to be crushed for the
greater good. Such emotions would equally be expected on deontological
models. Nor does the speed with which we make negative moral judgments
in such cases show that the judgments are merely emotion-driven: even
if there is not explicit reasoning going on in each case, the
emotion-laden intuitive responses may be informed by background moral
reflection and formation (Pizarro and Bloom 2003, Dancy 2014, Railton
2014). Philosophers who are less skeptical of the normative
explanations for our judgments will find it plausible that such
reflection has made us intuitively sensitive to morally relevant
distinctions--such as the distinction between doing something to
a public threat to direct it toward least harm vs. assaulting an
innocent person and using his harm to bring about less overall harm;
that sensitivity then shows up in our intuitive moral judgments, which
are no less justified just because they provoke strong emotions.



Indeed, philosophers who believe there are good reasons for
distinguishing morally between Trolley and Bridge are unlikely to be
convinced by the above debunking explanation, for the following
reason. Suppose we vary Bridge to equalize the cases for the factor
Greene emphasizes: instead of having to shove the man off the bridge,
all you have to do in Bridge Lever is flip a switch, and the switch
will activate a lever that knocks the bystander off the bridge in
front of the trolley. These cases are now equalized to be
"impersonal": neither now involves violence that is
"up close and personal". But does this variation change
our moral response? If it does not, and we find Bridge Lever again
objectionable (just like Bridge) while allowing for Trolley, then
Greene's proposed explanation would not work: we would need a
different explanation for this pair of cases, such as the
reason-giving explanation deontological philosophers would give. Even
with regard to the original pair of cases, while Greene may be right
that evolved dispositions against personal violence play some
role in explaining our reactions, this needn't be the whole
explanation. It may be that this is another case of
*overdetermination* (see section 2.4).


### 3.3 Corrective Uses of Evolutionary Biology in Normative Ethics



A less problematic kind of appeal to evolutionary theory has been made
even by those who fully recognize the autonomy of ethics and the role
of autonomous moral reflection. Darwinian evolutionary theory implies
that many other beliefs about the natures and origins of living things
are false. Human beings are not members of a species created by a
special act of a divine designer, but members of an evolved species
related by common ancestry to every other species on Earth. So insofar
as certain ethical views *rely* on assumptions about special
creation, they will be refuted by the success of evolutionary theory.
More weakly, insofar as certain ethical views have traditionally been
*supported* by claims about special creation, they will to that
extent lose some of their support. This would not show that they are
false or even unjustified, as there may be alternative sufficient
support for them. But in removing some of their common support,
evolutionary theory would pose a significant challenge to those who
had relied on that support (Rachels 1990).



Rachels takes such an approach against the common belief that human
beings have a special moral dignity that is much higher than the
status enjoyed by non-human animals. Such a belief has traditionally
been rooted in the idea that we are separate from other living things,
having been created specially in the image of God and endowed with
souls, giving us a special moral status. If evolutionary theory is
true, however, then this support is undermined: since *Homo
sapiens* evolved from other species, there is no sharp biological
separation between *Homo sapiens* and the rest of the living
world; there is instead a continuum through evolutionary history, with
no species created separately, in a divine image, or infused with
special souls. Thus, those who have based their beliefs about the
speical moral status of human beings on a creationist picture have a
problem: that picture is false, and the true picture does nothing to
support such a view.



Again, however, this does not show that the common view of special
human dignity is false or even unjustified. There may be other forms
of support for it that do not depend on creationist assumptions. Many
would argue, for example, that although we are related to other
animals, we are very different from even our closest primate
relatives, as (not to put too fine a point on it) a trip to the zoo
followed by a visit to the Library of Congress or the Metropolitan
Museum of Art will confirm. The vastness of the differences between
human and other forms of life on Earth is not erased by pointing out
that human beings got to be the way we are through contingent
evolutionary processes acting on brains similar to those of extant
apes, together with thousands of years of cultural evolution. It is
these real differences--regardless of how they came
about--that plausibly ground differences in the moral status of
human beings and other
 animals.[10]



There are more straightforward ways in which evolutionary biology, as
well as results from empirical moral psychology, can play a corrective
role in normative ethics. Evolutionary biology and comparative
genetics might, for example, be used to undermine false claims about
race, which underlie racist ethical claims. Experimental psychology
might be used to cast doubts on the moral condemnation of
homosexuality by supporting the debunking hypothesis that such
judgments stem from projected disgust. More generally, psychological
experiments can expose typical human pitfalls in moral judgment and
behavior--tendencies toward cruelty in conditions of power
inequality, or toward exaggerated moral condemnation when experiencing
disgust or stress. If we understand these facts about ourselves, we
can more effectively pursue and realize normative goals such as
non-violence or fairness by avoiding circumstances that lead to
cruelty, or by watching for and correcting distorting influences on
our judgment (Glover 2000; Appiah 2008, 49, 71-72, 110-11,
124; Buchanan and Powell 2018). As noted earlier, however, the
normative goals themselves will not have been set for us by
evolutionary biology or psychology. That task falls to informed moral
reflection.


### 3.4 The Question of Moral Progress



The idea of moral progress features prominently in reflection on the
history and future of moral thought and practice. While it may be
difficult to assess whether a society has made moral progress *on
the whole* over some period, it is not hard to find plausible
examples of progress along particular dimensions. The elimination of
the Atlantic slave trade, for example, and the development of the
modern human rights movement are compelling examples of widespread
moral progress. There are also plausible avenues to further
progress through improved conformity with legitimate moral norms
and through improvements in moral concepts, reasoning, and
understanding. We might then wonder: what are the drivers of such
moral progress (and likewise of moral regression when it occurs)? And
how might evolutionary biology bear on the prospects and strategies
for achieving moral progress (and avoiding moral regression)? Allen
Buchanan and Russell Powell take up these issues in wide-ranging
theoretical work that potentially has practical implications for a
number of current social and political problems, as discussed below
(Buchanan and Powell 2018, 2019; Buchanan 2020; see also the symposium
discussion of the 2018 book in *Analyse & Kritik* 41(2),
2019).



Different metaethical stances (see section 4) yield different
understandings of what moral progress might consist in as well as
different explanations for how moral progress has historically come
about. A moral realist, for example, will tend to conceive of moral
progress in terms of achieving a more accurate grasp of objective
moral truths and refining of our practices and institutions to align
more closely with them; and plausible examples, such as the widespread
liberalization of moral practices over the past few centuries, will be
explained largely by appeal to growing insight into moral truth
(Huemer 2016). By contrast, those who reject such appeals to objective
moral truths but wish to retain some notion of moral progress (perhaps
one that is extensionally very similar) will formulate a different
conception of progress and offer socio-cultural explanations of
progressive changes that do not rely on appeals to improved insights
into moral truth (Kitcher 2011). We will here set aside the many
complex issues attending these different approaches and focus on
this question: what bearing might our evolutionary past have on our
prospects and strategies for achieving the sorts of changes most agree
would constitute moral progress?



Suppose that the trend toward greater inclusivity with respect to the
scope of moral consideration--i.e., the elimination of racial and
gender barriers to the attribution of full human moral status, and the
extension of substantial moral considerability to a wide range of
non-human animals--counts as moral progress. One pessimistic
thought that might arise here on the basis of evolutionary
considerations is that human moral psychology may have evolved in such
a way as to place inevitable constraints on the possibilities for
achieving robust and sustained progress in these respects. While our
evolved moral psychology may contain certain altruistic elements,
these may be ultimately parochial, given the nature of the selection
pressures faced by our Pleistocene ancestors and assuming, as most
discussions do, that the long Pleistocene Epoch (roughly 2.6 million
years ago to 11,700 years ago, is the one primarily relevant to the
biological evolution of human psychological
 traits).[11]
 That is, these elements may be focused on kin and members of a
perceived in-group, with other countervailing dispositions posing
strong obstacles to extending that altruism to outside groups. Even if
we have some capacity for autonomous moral thought, enabling at least
some to grasp more inclusive moral truths, there may be such powerful
evolutionary constraints built into human moral psychology that such
ideas are unlikely to take hold and motivate progressive changes in a
widespread and sustainable way. There may be evolutionary limits to
the basic moral progress that we evolved primates can realistically
hope to achieve: we may just be saddled with a largely
*exclusivist, tribalist* morality.



Buchanan and Powell refer to this pessimistic idea as
"evoconservatism," and they note that it has been used
to argue against social and political movements organized around such
"cosmopolitan moral reform." And on the other side of
that same evolutionary coin, "evoliberals" share the same
premise about the constraints imposed by evolution on human moral
psychology but instead argue that since the progressive goals are
sufficiently desirable, we should look for biotechnological
interventions to alter human nature in such a way as to make them
realistically achievable. Buchanan and Powell reject both views
because they reject the underlying picture of evolved human moral
nature. Instead, they argue that the striking shifts that have already
occurred toward more inclusive morality, as well as consideration of
the conditions under which moral regression has occurred, support a
very different, more nuanced picture of evolved human moral
psychology--one without such pessimistic implications for deep
and lasting moral progress.



On their "biocultural" view, it is not just that human
rationality allows significant scope for autonomous moral reasoning
that can lead to greater inclusivity (as discussed in section 2.4
above), but that our evolved moral psychology itself contains the
seeds for such a shift (though it equally contains the seeds for
potential moral regression). They key idea is that our evolved moral
nature is neither inherently tribalist nor inherently inclusivist, but
contains *both* dispositions; their expression, however,
is conditional on the particular socio-institutional environmental
conditions that obtain (or are at least perceived to obtain). In some
conditions tribalistic dispositions will be engaged, while in other
conditions inclusivist dispositions can dominate. This is their
"adaptive plasticity" model of evolved human moral
psychology, according to which evolution has disposed us to think and
behave in certain ways under one set of (perceived) conditions, and in
very different ways under another set of (perceived)
conditions--this having been fitness-enhancing in our
evolutionary history. In particular, our tribalist tendencies are
activated when "cues of out-group threat" are perceived
(whether real or not), involving competition, disease, undermining of
in-group cohesion, and so on; by contrast, our inclusivist tendencies
are activated when such cues are less abundant or salient.



The hypothesis is that these adaptively plastic traits served the
biological interests of Pleiostocene humans well, achieving the joint
benefits of tribalism under conditions where it was fitness-enhancing
and more inclusive morality under conditions where tribalism was
counterproductive and greater inclusivity was beneficial. For us
today, this constitutes a mixed inheritance: on the one hand, it
provides us with the seeds for moral progress insofar as we can foster
and maintain the socio-institutional contexts that allow more
inclusive dispositions to flourish; on the other hand, it saddles us
with vulnerability to destructive tribalism when we find ourselves (or
even just *perceive* ourselves to be) in circumstances
characterized by sufficient out-group threat cues. Buchanan and Powell
argue that this makes human beings dangerously susceptible to moral
regression due to the manipulation of perceptions through demagogic
populism, for example--a danger that is exacerbated where
disinformation is rapidly spread through social media. If they are
right, then the situation is ripe for media-savvy politicians to
manipulate popular beliefs in ways designed to trigger the threat cues
that energize tribalist tendencies in thought, feeling and behavior
for political gain--from reflexive anti-immigrant nationalist
sentiment to racially charged scapegoating during a pandemic.



While these dangers cast doubt on the conviction that moral
progress is inevitable or even the natural default, the model proposed
by Buchanan and Powell leaves open a realistic hope for continued and
deepening moral progress: it is possible for humanity to make and
sustain deep moral progress, without being hamstrung by any inbuilt
evolutionary constraints; but it will require ongoing cultural efforts
to foster and sustain the socio-institutional circumstances that
enable the better aspects of human moral nature to predominate
(Buchanan, forthcoming). This is the practical message of this
biocultural theory of moral progress: moral progress is possible for
us without the need for biotechnological modifications of human
nature; but such progress is also fragile and cannot be taken for
granted (Buchanan and Powell 2018).


## 4. Evolutionary Metaethics



While evolutionary facts may do little to illuminate the
*content* of morality in the normative sense (apart from
shedding light on morally relevant facts), they are sometimes thought
to tell us something about the *existence* and *nature*
of morality in the normative sense. (See section 1.2 for the notion of
morality in the normative sense.) A number of philosophers have
claimed that evolutionary theory can be used to debunk certain
*metaethical* theories and perhaps to support others. One
relatively modest project along these lines would be to use
evolutionary biology to undermine Aristotelian appeals to natural
teleology in human life to account for ethical facts, along the lines
of Foot (2001). This evolutionary-based critique of
"teleological naturalism" in ethics (FitzPatrick 2000) is
discussed in the



> 
> Supplement on Natural Teleology in Ethics.
>  



Other projects involve using evolutionary biology to try to undermine
traditional
 moral realism--the
 view that moral judgments can be true (accurately representing moral
facts) when construed literally, that their truth does not depend on
our evaluative attitudes, and that we can know at least some of these
truths. Such arguments are taken to support moral skepticism
(according to which we cannot possess moral knowledge) or
 moral antirealism
 (for example, views that construe moral truths as functions of our
evaluative attitudes, or expressivist views according to which moral
judgments function to express attitudes, acceptance of norms, etc.,
rather than to represent moral facts, or error theoretic views
according to which all moral judgments are false).


### 4.1 General Evolutionary Debunking Arguments



As discussed in section 2, evolutionary accounts of the origins of our
capacity to be guided by moral judgments do not require any appeal to
the comprehension of moral *truths* by our hominin ancestors,
or even to the existence of such truths. Such stories require only
claims about natural selection pressures having favored the
development of such a capacity and tendency because of the positive
effects such traits had on biological fitness (Kitcher 2006a, 176, and
2011; Joyce 2006, 131, 184; Street 2006, 127 f.; Griffiths and Wilkins
2015). Should this fact undermine our confidence in the existence of
moral truth or in the possibility of moral knowledge (at least if
moral truths are understood to be objective, i.e., independent of our
evaluative attitudes)?



Proponents of epistemic 'evolutionary debunking arguments'
think it should, arguing either that evolutionary considerations
support moral skepticism (Joyce 2006, 2013, Forthcoming) or that they
at least undermine traditional moral realism by providing a defeater
for our moral beliefs *if* correctness for moral beliefs is
construed in a realist fashion as accurate representation of objective
or independent moral truths (Street 2006, 2008). (For discussion of
these arguments, see Copp 2008, Kahane 2011, Enoch 2011, Skarsaune
2011, Shafer-Landau 2012, Berker 2014, Fraser 2014, FitzPatrick
2014a,b and 2017a,b, Vavova 2015, Rini 2016, Levi and Levi 2020, among
many others.)



On the face of it, the mere fact that natural selection would not have
'designed' our moral faculties to track moral truths
accurately (as it plausibly designed our perceptual faculties to track
facts about medium sized objects in typical human environments) is not
obviously problematic. There are, after all, lots of cases where we
seem to be able to grasp genuine truths even though those truths play
no role in the story of how our basic mental capacities evolved. We
are able to grasp truths of quantum field theory or higher dimensional
topology or, for that matter, philosophy (or so we are assuming in
even engaging in this debate) even though those truths had nothing to
do with why the basic mental capacities underlying these abilities
evolved in our Pleistocene ancestors. Those capacities evolved in
response to selection pressures in ancestral hunter-gatherer
environments, and we have simply learned how to develop, train and
exercise them in cultural contexts to discover truths that go far
beyond any that were relevant to the evolution of those underlying
capacities. Philosophers who endorse some form of moral realism have
typically believed that we've done the same thing in grasping
moral truths (see sections 2.4-2.5).



Suppose, however, that evolutionary influences not only did not design
our faculties to track moral truths, but *did* positively shape
them in ways that have pervasively conditioned the *content* of
our moral thought and feeling, through evolved emotional dispositions
or "domain specific modules" that provide us with
inherited moral instincts that shape our beliefs. Debunkers have
claimed that this is the case and argued that it has deep metaethical
implications. Though there are a variety of formulations of such
arguments, with somewhat different targets (some attacking moral
knowledge itself, others seeking only to undermine moral realism by
showing that it would saddle us with moral skepticism), a core
argument based on the work of Sharon Street may be spelled out roughly
like this:


#### Evolutionary Debunking Argument:



"Our system of evaluative judgments is thoroughly saturated with
evolutionary influence," because of the role natural selection
played in shaping our underlying psychological dispositions (Street
2006, 114). But natural selection shaped those dispositions simply
according to which variations best contributed to the biological
fitness of our hominin ancestors, rather than in ways that would be
expected to track independent moral truths as such, even if they
existed. That is, natural selection rewarded moral belief-forming
dispositions that yielded whatever moral beliefs led to behaviors that
caused hunter-gatherers to out-reproduce their peers and propagate
their genes more effectively, regardless of whether or not these
beliefs happened accurately to represent a realm of independent moral
truths. (The same would have been true for religious beliefs and
theological truths: all that mattered were the relevant effects on
genetic propagation, as through increased cooperation and rule
following based on belief in a watchful god, assuming the religious
belief-forming dispositions were under genetic control and subject to
selection pressures. Theological truth or falsity was beside the
point.) But since realists do not understand moral truths simply to be
a function of what helped Pleistocene hunter-gatherers to maximize
their reproductive output, it would be a *sheer coincidence* if
our evolutionarily shaped moral beliefs happened to align with the
moral truths, accurately representing them. And we are not justified
in thinking that any such sheer coincidence has taken place.
Therefore, we cannot have any justified confidence that our moral
beliefs accurately represent independent moral truths of the sort
posited by realists. That is, our justification for our moral beliefs
would be defeated by these evolutionary considerations, at least if
truth for moral beliefs consists in accurately representing
independent moral facts, as realists maintain. (Epistemic internalists
may deny that the facts cited above would by themselves render our
moral beliefs unjustified, even on a realist model. But even they
should agree that *once we become aware of those facts* our
moral beliefs would thereby be rendered unjustified, at least given a
realist model of what it would be for them to be true.) So realism
saddles us with skepticism. And if such skepticism is implausible,
then realism must be rejected in favor of an antirealist view (such as
moral subjectivism) that would still allow for justified moral beliefs
despite evolutionary influences and our awareness of them (Street
2006, 2008).



One response to this argument, on behalf of naturalistic realism,
grants the claim of pervasive evolutionary influence on the contents
of moral beliefs but challenges the claim that this should undermine
our confidence in these beliefs. David Copp (2008), for example, has
argued that on the conception of moral truths implied by his
society-centered moral naturalism, it is plausible to suppose that a
moral psychology shaped by natural selection in social contexts would
yield moral beliefs that track moral truths at least reasonably well
as a first approximation. On such a view, moral truths are grounded in
moral standards having to do with codes that would enable societies to
meet their basic needs (continued existence, stable cooperation among
members, internal harmony and peaceful relations with other
societies). Given the account of the evolution of human moral
psychology sketched in section 2.3, involving the evolution of a
capacity for normative guidance in connection with promoting social
stability and cooperation (ultimately, of course, because of effects
on genetic propagation), and further contributions of cultural
evolution toward the development of moral codes fostering those same
goals, many of our moral beliefs would naturally have to do with
conditions for social stability and cooperation. Since on the proposed
naturalistic view this is just what moral truths are about, there
would thus be a tendency for our moral beliefs to have been shaped in
ways that do tend to track moral truths, especially combined with
continued cultural developments for correcting beliefs or attitudes
that fail to contribute to these social goals.



Street (2008) has replied to this proposed way out of the problem, in
part, by noting that Copp's strategy relies on his intuitions
about what the moral truths are, as reflected in his society-centered
moral theory. But those are precisely the intuitions of an
*evolved* theorist, *ex hypothesi* influenced by the
same evolutionary factors that influenced the moral beliefs in
question. So of course we can expect there to be a decent alignment
between our evolutionarily shaped moral beliefs and the moral truths
described by a moral theory spun by the very same evolutionarily
shaped mind. Such a move, she argues, therefore cannot really help the
realist. It would be different if God independently (and convincingly)
revealed to us what the moral truths are, so that we could then go
check our moral beliefs against them and perhaps discover that they
line up pretty well; but instead, all we're doing is comparing our
moral beliefs with a purported list of moral truths yielded by a
theory we find plausible precisely because it is appealing to our
evolved sensibilities (though see Locke 2014 and FitzPatrick 2014b for
some complications here).



Similar and even worse worries arise for a subset of non-naturalists
who grant the debunkers' claims about pervasive evolutionary
influence on our moral beliefs and also insist that moral properties
and facts have played no role at any point in the formation of our
moral beliefs, which have instead been caused by some 'third
factor' that happens to have brought about the desired
correlation (Wielenberg 2010, Enoch 2011). One can, of course, tell a
story about some such third factor: perhaps the 'evolutionary
aim', survival and reproduction, also happens to be good, so
that in giving us moral beliefs that promoted survival and
reproduction evolution also happened to give us moral belief
dispositions that are largely accurate (Enoch 2011). But the question
is again how one is entitled to rely on moral intuitions (e.g., that
survival and reproduction are good) in telling that story, even
*after* granting that those intuitions are simply the product
of 'morally blind' causes, i.e., causes operating entirely
insensitively to moral properties and facts. There are also deeper
difficulties concerning oversimplifications in such accounts (e.g.,
regarding the 'evolutionary aim') and the fact that on
this approach the correlations between moral beliefs and moral truths
ultimately rest on a mere accident, raising doubts about whether such
accounts can really make sense of the kind of moral knowledge and
understanding realists think we have (Bedke 2009, FitzPatrick
2014b).



Realists have further resources, however, which can be deployed to
supplement a move such as Copp's, in a way that blocks the above
dialectical worry raised by Street. Street's objection to Copp,
after all, has teeth only if the realist has already granted the
strong claims about "tremendous" and pervasive
evolutionary influence "saturating" our moral beliefs
across the board. It is far from clear, however, why realists should
accept such strong claims to begin with. As discussed in section 2, it
seems doubtful that the scientific evidence itself supports such
strong claims about the etiology of 'our' moral beliefs. Even
if there is significant evolutionary influence on the content of many
of our moral beliefs, it remains possible that many of our moral
beliefs are arrived at partly (or in some cases wholly) through
autonomous moral reflection and reasoning, just as with our
mathematical, scientific and philosophical beliefs.



Consider how a moral realist will approach the above debunking
argument. It is intended to show us that realism is untenable, which
of course means that this conclusion cannot just be *assumed*
from the start. Yet if we begin the argument allowing that there may
be independent moral truths, then why should we accept the initial
claim about the pervasive influence of evolutionary forces on the
content of our moral thinking in the first place? If there are
independent moral truths, then we may plausibly have grasped many of
them through autonomous exercises of our capacities for moral
reflection, whereby we have come to recognize good reasons for
thinking certain moral propositions to be true, by correctly grasping
that certain features of actions are wrong-making, say.



For example, your belief that human trafficking is wrong is plausibly
best explained by citing your reasons for holding it: you believe
it's wrong for the reasons you give, such as the fact that it
causes tremendous suffering and deprivation, violates the basic
dignity and rights of its victims, and so on. From a realist
perspective, these features you cite in giving your reasons for the
belief are in fact wrong-making features of human trafficking, i.e.,
features that make trafficking wrong and therefore *make true*
the moral proposition that human trafficking is wrong. On this
picture, you therefore believe that trafficking is wrong because it
*is* wrong and you've come to recognize the moral fact that
it is wrong by recognizing the reasons why it is wrong (FitzPatrick
2016).



Unless realism has *already* been rejected for other reasons,
then, this picture is an open possibility at the start of the debate,
which means that the realist is entitled to hold that many of our
moral beliefs are in fact not merely caused by evolutionary and other
'morally blind' influences, but are instead well-grounded
responses to moral reality. That is, the realist need never grant the
debunker's strong claims to the effect that our moral beliefs
across the board are saturated with evolutionary influence (see
section 2). Perhaps some are and some aren't, and the proportions
will depend on the extent to which we've successfully exercised
autonomous reflection in arriving at our moral beliefs, which is a
wide open question. If there are enough autonomous beliefs in the mix,
and we can identify them, then the rest of the argument will not go
through (FitzPatrick 2014a,b; 2016,
 2017a,b).[12]



The debunking argument would be strengthened if we had good reason to
be skeptical about autonomous moral reflection. In this vein, Street
claims that whatever moral reflection and reasoning we engage in is
limited merely to assessing "thoroughly contaminated"
evaluative beliefs using "tools of rational reflection [that
are] equally contaminated" (Street 2006: 124). The problem,
however, is that this claim is based upon the very premise in
question: the tools of reflection are allegedly thoroughly
contaminated *because of* the "tremendous"
evolutionary influence on the content of "our" moral
judgments across the board; yet our question is why we should believe
the latter in the first place. Until we are given independent reason
to discount the power of moral reflection so radically, treating it as
nothing more than using some rotten apples to judge other rotten
apples, we seem to have little reason to dismiss the possibility of
autonomous moral reflection, and therefore little reason to accept the
initial claim of pervasive "saturation" of our moral
beliefs with evolutionary influence.



Street actually casts her argument in terms of a "Darwinian
dilemma" for realists, which centers around the following
question: what is the relation between the evolutionary shaping of
moral judgments and the independent moral truths posited by realists?
(Street 2006, 109). As already noted, the best scientific accounts
suggest that there would be no special relation here, even if such
moral truths existed. But if there is no special relation between this
evolutionary shaping and independent moral truths, then we would have
no reason to trust our moral beliefs, which are as likely to be
off-track as on-track, leading to moral skepticism. So the realist
seems to face a *dilemma*: reject the best available science or
lose all justification for our moral beliefs.



As brought out above, one way out of the dilemma for a realist is
simply to deny that the evolutionary influence on the content of our
moral beliefs is as pervasive as Street claims. The realist can grant
that where such influence does exist we cannot assume that it would
have pushed our beliefs toward moral truth: it may accidentally have
done so in some cases (e.g., influencing us to think we have
obligations to care for our children) and it might have been
distorting in others (e.g., influencing us to downplay obligations to
those who do not belong to our in-group). But this is not a problem if
we also have a culturally developed capacity for autonomous moral
reflection and reasoning that allows us to attain moral knowledge
despite the presence of *some* unreliable influences. Realists
will claim that we don't *need* natural selection to have
given us moral beliefs that track moral truths, any more than we need
this in science or philosophy: all we need is for natural selection to
have given us faculties that we can develop, train and use in ways
that reliably track moral truths, and enough freedom from
evolutionarily given instincts that we can so exercise those
faculties.



Finally, Street challenges the realist to specify what faculty or
capacity might ground our capacity to arrive at independent moral
truths, how the former evolved, and how the latter could plausibly
have arisen as a byproduct of it. She claims that there is no
plausible story to be told here, since the capacity to grasp
independent moral truths would have to be "a highly specialized,
sophisticated capacity" akin to the human eye, and no such
entity could plausibly emerge "as the purely incidental
byproduct of some unrelated capacity that was selected for on other
grounds entirely" (Street 2006, 142-43). But the
realist's story needn't take that form. The claim will be just
that our capacity to grasp moral truths--like our capacity to
grasp philosophical truths about metaphysical necessity, say--is
simply a byproduct of our general capacities for critical reasoning,
combined with the evolved capacity for forming and employing normative
concepts in our thinking and decision-making.



A related but somewhat different debunking argument focuses on the
origins of moral *concepts* (Joyce 2006, chap. 6). It begins
with the claim that we have a *complete* *non*-moral
genealogy of our moral beliefs--a complete explanation of how
we've come to believe what we do, which does not require any
appeal to moral *truths*. Instead, we explain the origins of
our moral concepts--such as fairness, justice, and guilt--in
evolutionary terms, recalling that natural selection would have
rewarded genetic propagation, not the tracking of moral truths, in
shaping them; and then we explain our beliefs employing those moral
concepts in familiar sociological and psychological terms. The claim
is then that the existence of such a non-moral geneaology of moral
beliefs makes the notion of moral truths "explanatorily
superfluous"--just as truths about witches are
explanatorily superfluous given a complete genealogy of beliefs about
witches that does not involve any appeal to truths about witches. And
if moral truths are explanatorily superfluous, then we should not
posit them, any more than we posit truths about witches: we should
remain agnostic about moral truth and give up any claims to moral
knowledge. In other words, evolutionary biology leads to moral
skepticism.



The critical questions about this argument parallel those raised about
the previous one. Even if it is granted that crude versions of our
*concepts* of fairness or guilt originated through evolutionary
processes in our hominin ancestors, independently of any connection to
moral truths, it remains possible that through cultural evolution we
have developed refined *conceptions* of fairness or guilt that
can be employed in epistemically respectable ways (FitzPatrick 2014a).
Regardless of how and why the concept of fairness originated, why
should we doubt that we can today use a refined conception of fairness
to state moral truths, such as the truth that race-based voting laws
are unfair and wrong? If there are grounds of skepticism about this
they would have to lie in reasons to doubt the soundness of our
first-order moral arguments about fairness, rather than in claims
about how and why a crude version of the concept first arose (Nagel
1997).



Absent such doubts, it's not clear why the mere fact of historical
evolutionary influence should undermine our confidence in our moral
claims. To draw an analogy, should a theist give up her belief just
because crude, ancestral forms of religious belief can be causally
explained without appeal to theological facts? Perhaps she will if she
finds no good reasons for her own belief, and concludes that it is to
be explained along similar lines. But if she has reflected on the
matter and been persuaded by a "cosmological argument from fine
tuning," for example, then it seems she might reasonably
maintain her belief, taking her employment of the concept of a deity
to be epistemically legitimate despite the fact that other employments
are subject to debunking evolutionary, sociological and psychological
explanations.



In general, the worry about Joyce's debunking argument is similar
to the worry about Street's: unless we start out *already*
assuming (against the realist) that there are no knowable moral
truths, it is hard to see why we should accept Joyce's premise
that we possess a *complete* *non*-moral geneaology of
moral judgment, and hence that it is explanatorily superfluous to
posit moral truths. Whether or not the non-moral geneaology is
complete is precisely what is in question in ongoing metaethical
debates: realists, who posit knowable moral truths, can reasonably
hold that the correct explanation for at least many of our moral
beliefs *does* appeal to moral truths or facts that we have
grasped, while anti-realists, who deny the existence of such truths,
claim that the correct explanation for all of our moral beliefs
involves no such appeal. The issue remains controversial. So unless
one has independently settled that issue against realism, one is
unlikely to accept the premise that there is a complete non-moral
genealogy of our moral beliefs: there may well be a *partial*
non-moral genealogy, for the sorts of reasons Joyce gives, but it will
be *complete* only if *none* of our moral beliefs are
the result of our having grasped moral truths; and this negative claim
will be very unlikely if there are in fact knowable moral truths
(since we would plausibly have grasped some of them, and they would
thus figure into the explanation of some of our moral beliefs). We
should therefore feel compelled to grant Joyce's premise that
there *is* such a complete non-moral genealogy only if we have
*already given up* on the idea of knowable moral truths. But
that makes it hard to see how the argument as a whole can be used to
persuade anyone who doesn't already accept its conclusion.



It is worth noting that the appeal to evolution to support general
skeptical worries about ethics is not in fact new: it goes all the
back to Darwin himself. Consider the following provocative, fanciful
reflection (later echoed closely by E.O. Wilson 1978, 204-206),
which at least suggests a skeptical argument closely related to the
debunking arguments examined above:



> 
> It may be well first to premise that I do not wish to maintain that
> any strictly social animal, if its intellectual faculties were to
> become as active and as highly developed as in man, would acquire
> exactly the same moral sense as ours. In the same manner as various
> animals have some sense of beauty, though they admire widely different
> objects, so they might have a sense of right and wrong, though led by
> it to follow widely different lines of conduct. If, for instance, to
> take an extreme case, men were reared under precisely the same
> conditions as hive-bees, there can hardly be a doubt that our
> unmarried females would, like the worker-bees, think it a sacred duty
> to kill their brothers, and mothers would strive to kill their fertile
> daughters; and no one would think of interfering. Nevertheless the
> bee, or any other social animal, would in our supposed case gain, as
> it appears to me, some feeling of right and wrong, or a conscience
> (Darwin 1871, 73).
> 



The argument at least suggested by this passage is that our moral
sense, which generates our moral beliefs, has the shape and content it
has because of the contingencies of human ecology; had creatures with
a very different ecology, such as bees, come to be rational, they
would thus have developed a very different moral sense suitable to
their ecology. But then which of these very different moral senses
could be expected reliably to track moral truths (if they exist)? The
answer seems to be: *neither* (unless we simply relativize
moral truths to various possible ecologies, taking such truths to
reduce to facts about effective genetic propagation--though as we
saw in section 3, such a move has little moral plausibility). For
moral senses are contingent products of particular ecologies in a way
that cannot be expected to track independent and stable moral truths.
We and the hypothetical rational bees will thus have very different
moral outlooks, each of which is explicable in terms of our respective
ecologies and will seem quite natural to those who occupy the relevant
ecology (while the other's outlook will seem bizarre), but neither
of which seems to have any claim to be a reliable guide to *moral
truth* (as usually conceived). This imaginary exercise in
perspective thus seems to support moral skepticism: the very idea of
independent, stable moral truths will seem suspect (playing no role in
the explanation of the origins of various possible moral senses), and
our confidence that our moral sense would track them in any case will
seem unwarranted.



What such an argument overlooks, however, is precisely the factor of
*autonomous moral reflection* that the bees' imagined
rationality would bring with it (see sections 2.4-2.5, and
McDowell 1995). True, we might expect relatively unreflective and
tradition-bound bees to speak of "sacred duties" to kill
brothers or fertile daughters, in a way that lines up with the
relevant genetic relations that figured into the evolution of their
given moral senses. But we could equally expect more reflective bees
(the buzzing philosophers among them) to raise the question whether
they really had *good reason* to do everything that their
evolution has disposed them to do in the service of maximizing their
genetic propagation. These more philosophical bees might consider the
possibility that some potential goods of bee life, in the context of
ongoing innovations in rational bee culture, might be available to
them if they resisted certain impulses and acted differently; and this
might lead to the development of at least partly autonomous moral
norms, and hence moral senses that are a complex mixture of inherited
dispositions and rational judgment.



If bees became rational, then, there is no reason to suppose that
their moral sensibilities would simply reflect their ecology any more
than human moral sensibilities simply reflect human ecology: to the
extent that they are really rational, we should expect some autonomous
reflection, and perhaps even significant overlap with autonomous human
moral reflection, as we both strive for something beyond the merely
biologically useful (FitzPatrick 2000, 355-56, and 2017b). This
is not to suggest, of course, that moral truths or objective moral
norms, if they exist, will be exactly the same for human life and for
rational bee life, or for actual human life and human life imagined
under vastly different ecological circumstances. On any plausible view
of morality, there will be significant variation in moral principles
and/or their applications where there is significant variation in the
basic facts of life. Just as we could never live just like bees, bees
could never live just like humans, and no reasonable morality would
demand such a thing. Even a realist, then, will grant a significant
degree of cross-species moral relativism (or counterfactual moral
relativism for deeply different courses of human evolution). But it
needn't be the extreme and implausible relativism linking true
moral standards simply and directly to ecology, and whatever moral
truths might obtain for each species might well be accessible to
members of each species through autonomous moral reflection, with at
least some points of convergence.


### 4.2 Selective Evolutionary Debunking Arguments



Before leaving the topic of evolutionary debunking arguments, it
should be noted that in addition to the general arguments considered
above, which are aimed at debunking morality (or in Street's case,
debunking a realist construal of morality) *as a whole*, there
are also evolutionary debunking arguments meant instead just to target
a *selected range* of moral beliefs as epistemically suspect.
Such selective debunking arguments may be deployed by moral realists
who reject general debunking arguments in this domain but nonetheless
wish to use similar tactics to discredit certain kinds of moral belief
as part of advancing their own *normative* ethical project.
They might argue, for example, that while the deontological beliefs
held by their opponents can be successfully debunked by appeal to
evolutionary considerations, their own utilitarian ethical beliefs are
immune from such debunking, stemming from autonomous rational
reflection rather than from evolved psychological modules shaped by
the distorting influences of natural selection.



This is the strategy adopted by Katarzyna de Lazari-Radek and Peter
Singer (2014) in an effort to support Sidgwick's principle of
Universal Benevolence, i.e., impartial utilitarianism. That principle
is inconsistent not only with moral egoism but with any moral
stance that incorporates limited forms of partiality (such as special
duties to family and friends even when not utility-maximizing, or
constraints against taking certain means
when promoting utility, or moral permissions to favor
oneself or loved ones to some degree over strangers). So in order to
discredit such competing moral views, they claim that one can tell
debunking evolutionary stories to 'explain away' these
non-utilitarian moral beliefs as unreliable products of distorting
evolutionary influences: people believe such things only because
natural selection shaped human moral psychology in the direction of
selfishness and at best parochial altruism, for Darwinian reasons
having nothing to do with moral truth. Then, in effect, they treat the
possibility of telling such debunking evolutionary stories as
sufficient to undermine epistemic justification for the targeted moral
beliefs. At the same time, however, they maintain that their own
favored ethical beliefs, involving strict impartiality, are
invulnerable to any similar treatment, so that we can remain confident
in the rationality of utilitarian morality.



There are reasons to doubt whether this sort of theoretically
ambitious but selective evolutionary debunking strategy is a viable or
stable one (Kahane 2011 and 2014, Rini 2016, FitzPatrick 2017a).
A natural worry is that if such debunking arguments really worked
against opponents of utilitarianism in the manner suggested, then
similar arguments could equally be deployed against
utilitarianism if we play by the same rules. The selective
debunking arguments used by de Lazari-Radek and Singer give a great
deal of negative epistemic weight to the mere existence of possible
debunking explanations which, *if true*, would clearly pose a
problem for the targeted beliefs (even though it remains a wide open
question whether such explanatory stories are in fact true). That is,
they give great weight to the mere ability to *tell a plausible
debunking story* according to which non-utilitarian moral beliefs
would turn out to be problematically rooted in 'contaminated
starting points' (psychological dispositions resulting from
morally blind evolutionary forces) that have merely been refined over
time by culturally conditioned causal influences operating equally
blindly to moral truths. This raises problems for them, however,
because one can easiliy enough come up with similar debunking stories
about *utilitarian* beliefs, according to which they would
equally turn out to be problematically shaped by morally-blind
evolutionary forces that contaminated the starting points.



Here is just one way such a story could go (FitzPatrick 2017a). Recall
the possibility discussed in sub-sections 2.2 and 2.3, that in early
ancestral environments involving mostly small in-group interactions,
where there were relatively few opportunities for 'wasting'
altruistic tendencies on outsiders, natural selection gave rise to
some fairly *indiscriminate* dispositions involving sympathy
and altruism. (Or again, recall the adaptive plasticity model from
Buchanan and Powell 2018, discussed in section 3.4, which posits
environmentally sensitive inclusivist tendencies as part of evolved
human psychology.) As long as such indiscriminate altruism contributed
more to fitness in that environment than it detracted from it through
occasional 'misfirings' of such sentiments and behaviors
directed at non-cooperators, it could very well have evolved as a
simple fitness-enhancing mechanism (Kitcher 2006b). Someone who wishes
to debunk impartial utilitarianism might then tell a story according
to which the utilitarian's impartial sympathy and concern is
nothing but an extension of this evolved psychological trait, whereby
it is systematically 'misfiring' (from a biological point of
view) in our current environment. More precisely, the story would be
that current utilitarian beliefs represent a cultural refinement of
such evolved tendencies *via* an application of reasoning, such
as the consistency reasoning utilitarians employ in arguing for an
"expanding circle" of moral concern and an increasingly
impartial altruism. The debunker will claim that however rational such
inferential steps may be in themselves, they are still just operating
on certain moral starting points that are 'contaminated'
by evolutionary influence: namely, deeply ingrained moral intuitions
about the *intrinsic badness of suffering* wherever it occurs,
or the goodness of pleasure, which trace back to evolved psychological
dispositions to recoil at suffering and injury, and to feel sympathy
for others. Basic utilitarian moral intuitions, no less than
non-utilitarian intuitions, may ultimately be nothing but illusions
foisted on us by our evolutionary history, rooted in contaminated
starting points (Ruse 2006). In both cases, proponents of the moral
views in question have moved well beyond the original evolved
dispositions, through culturally-developed reasoning that has refined
them in various ways. But if this doesn't save non-utilitarian
moral beliefs given the debunking story about the contaminated
starting points, then it won't save utilitarian moral beliefs
either.



Now de Lazari-Radek and Singer might reasonably wish to counter such
debunking attacks by claiming that even if there are such evolutionary
influences at the root of their intuitions about the badness of
suffering or the propriety of impartial altruism, the reflection and
reasoning that has taken place over centuries of sophisticated moral
inquiry has not merely provided for more consistent applications of
evolutionarily contaminated dispositions: it has instead amounted to
the intellectual *discovery of good reasons* to believe the
contents of utilitarian moral claims to be *true*. This
philosophical possibility certainly remains on the table and
hasn't been shown not to obtain simply because an aspiring
debunker can tell a debunking story according to which it doesn't.
And such a reply would indeed be a plausible response to the debunker,
making precisely the point emphasized earlier in section 4.1, in
responding to general debunking arguments. The problem, however, is
that if they are entitled to make this response to the debunker on
behalf of utilitarian moral beliefs, then so are their opponents on
behalf of non-utilitarian moral beliefs: what's good for the
utilitarian goose is good for the non-utilitarian gander.



In other words, to escape evolutionary debunking themselves, it seems
that de Lazari-Radek and Singer will have to allow that the mere
existence of a possible evolutionary debunking explanation for a set
of moral beliefs does not undermine epistemic justification for them.
It matters whether or not that story *is actually the correct*
explanatory story, including its claim that the beliefs in question
are *exhaustively* accounted for simply in terms of the
morally-blind, extraneous causes in question, rather than partly
through rational grasp of good reasons for believing their contents to
be true; and merely being able to tell a debunking story does not
establish such a strong claim. Once this is recognized,
however, the same principle applies to just the sorts of
debunking arguments they have deployed against non-utilitarians, who
can thus avoid them in the same way.



One or more of the debunking stories could, of course, still turn out
to be true, and they do need to be taken seriously as
*possibilities.* The critical points raised here are just,
first, that it is unclear whether debunking arguments really have
compelling force against those who haven't already
independently rejected the positions being targeted (showing them that
their beliefs are really bunk); and second, that it may be
hazardous for those who reject general evolutionary debunking
arguments in ethics to attempt to use similar arguments selectively
against competing normative ethical views. Such potential
explanations could, however, still play a supporting role within a
broader set of moral arguments, contributing a possible theory of
error helping to explain why some people may believe certain moral
claims or theories even though they are false.


### 4.3 Evolutionary Biology and Expressivism



A less ambitious claim made by some antirealists is that the account
in section 2.3 of the origins of our capacity for normative guidance
at least *lends support to* or *fits naturally with* an
*expressivist* metaethical view--the view that moral
judgments do not even purport to state moral facts, but instead
express non-cognitive states such as attitudes or acceptance of
certain norms, etc. (Gibbard 1990; Kitcher 2006a). Suppose the human
capacity for normative guidance is indeed an adaptation that evolved
in connection with social coordination, cooperation and stability.
This capacity involves being in the state of *accepting a
norm*, which we should thus expect to be a standard part of human
moral psychology and its capacity for "linguistically infused
motivation" (Gibbard 1990, 55). This may lend support to a
norm-expressivist approach to normative judgment, insofar as such an
approach focuses precisely on the notion of accepting a norm, and the
evolutionary story provides good reason to suppose that accepting a
norm is a "natural, biological phenomenon" (61).



It is less clear, however, whether anything stronger than this can be
said. Suppose it's true that we evolved a capacity and tendency
for normative guidance because of the coordinating social function
achieved by the expression of norm acceptance. Not only does this
leave open what we *now* use that capacity to do, but it even
leaves open what exactly our ancestors did with it. One possibility is
that the activity they were engaged with was *non-cognitive*:
they were merely expressing non-cognitive states comprising attitudes
and states of norm acceptance. Kitcher (2006a) suggests that this is
the metaethical picture best supported by the evolutionary story. But
Joyce (2006, 175-76) has disputed this. Even granting that the
*biological* function of moral judgment is social coordination,
the *linguistic* function of moral judgments could go either
way: it may be that the biological function was carried out through
non-cognitive expressions of norm acceptance, but it may equally
instead be that it was carried out through *cognitive*
judgments involving *claims to objective validity*. Indeed, the
social function might be all the better served if those making moral
judgments firmly believe in objective values and assert those beliefs,
even if they are in fact making a projective error in doing so, as
error theorists claim. Compare: even if religious belief has a
biological function (e.g., reducing anxiety), it wouldn't follow
that religious assertions are non-cognitive and so aren't really
assertions, and the story might be more plausible if it is assumed
that they *are* genuine assertions (Joyce 2006, 176, 208; Ruse
2006).



Thus, although the evolutionary story fits naturally with a merely
non-cognitivist metaethical view, it may fit equally well with a
cognitivist view. If one rejects the existence of moral truths, the
latter would then lead to an error theory (Mackie 1977). But as
discussed in section 4.1, it is far from clear how much support
evolutionary biology itself lends to moral anti-realism or irrealism.
It is consistent with plausible evolutionary stories that although our
capacities for normative guidance originally evolved for reasons that
had nothing to do with moral truths as such, we now regularly employ
them to deliberate about and to communicate moral truths. So all three
metaethical views discussed here--expressivism, error theory and
moral realism--remain on the table.