Thomas
Nagel reviews Jonathan Haidt’s The
Righteous Mind: Why Good People Are Divided by Politics and Religion (along
with Dignity: Its History and Meaning
by Michael Rosen) in The New York Review
of Books. Here is Nagel’s summary of
Haidt’s theory:
Haidt’s empirical theory, which he calls “moral foundations
theory,” is an example of evolutionary psychology. It is the hypothesis that a
set of innate “modules” of moral response were fixed in humans by natural
selection, and that these responses, further shaped by cultural evolution in
various more specific forms and combinations, underlie the widely divergent
moralities that we observe not only across the globe but within pluralistic
cultures like that of the United States…
Haidt distinguishes six basic types of moral response, which
he likens to distinct taste receptors, so that different moralities are like
different cuisines in the use they make of these responses. Each type manifests
itself through intuitive emotional reactions, positive and negative, to a
specific value or its violation, so he gives them double-barreled names:
care/harm, liberty/oppression, fairness/cheating, loyalty/betrayal,
authority/subversion, and sanctity/degradation. Haidt believes that all these
responses developed in their basic innate form because they suppress or
regulate self-interest and make cooperation possible among people who are not
close relatives.
I am cutting and pasting here
to isolate the following topic.
Specifically, Haidt argues that group selection—selection
for genetic traits whose presence benefited social groups of early humans in
competition with other groups, rather than individual selection for traits that
enhanced the reproductive success of individuals in competition with other
individuals—is responsible for the main moral dispositions. The existence of
group selection is a highly contentious issue in evolutionary biology. Haidt
defends it in this case on the ground that moral norms can include cheap
enforcement mechanisms, such as forms of group pressure, that cancel the
genetic advantage for any individual of trying to benefit from the group’s
success while not following the norms—free riding, in other words.
Individual natural selection can explain psychological
traits that benefit the individual and his close kin; but group selection, he
argues, is needed to explain those traits that benefit individuals only by
sustaining norms that preserve the cohesion of the group.
As Nagel observes, group
selection is a very controversial issue in Darwinian Theory. As the argument is frequently put, any altruistic
trait that benefitted the growth of a group as a whole without conferring a
reproductive benefit on the individual altruist against other members of the
group would quickly go out of business. As
the group grows relative to other groups, the portion of altruists would shrink
and disappear. Thus group selection
cannot work.
One way to make group selection
work would be for groups to continually break up and reform. If the group-benefit trait works to increase
the size of the group faster than individual selection within the group works
against the altruists and groups break up and reassemble faster than the latter
can complete its work, altruists might be sustained in the general population.
Another way to make group
selection work would be for the altruists to have a way of purging
non-altruists from the group. Haidt
argues that group selection is necessary to explain the evolution of moral
instincts. I would point out that the
obverse is equally true. Moral instincts
are necessary to make group selection possible.
Whether group selection is a
common feature of creatures other than human beings is to be sure difficult to
demonstrate. That natural selection
favors human beings who can cooperate with one another much more effectively
than other social animals because the moral instincts allow such persons to
trust one another seems very likely. The
moral instincts are clearly not limited either to direct self-interest or to a
preference for genetic relatives. Young
children will readily cooperate with individuals who they have just met, coming
to their aid or engaging them in games.
Once cooperation has begun, the child will expect the partner to keep
playing the game.
I think Haidt is right to
believe that group selection is necessary for the moral instincts to
evolve. I think also that something like
moral instincts are necessary for group selection to work among social
animals.
