opportunities for passing on the organism’s genes, the genes that compel the
organism to behave in such a way should disappear from the gene pool in the
long run. It is also evident, however, that many species live in cooperative
social groups and cooperation seems to provide benefits in coping with a
variety of problems. Taking an evolutionary approach to morality helps us
explain the presence of moral judgment, actions, and motivations in humans.
First, an evolutionary approach addresses the problem of why pro-social
tendencies evolved at all. Second, it examines the evolution of particular traits
that underlie such tendencies.
Altruism is a concept that has a somewhat different meaning in evolution-
ary theory than in everyday parlance. The meaning of“altruism”in evolu-
tionary theorizing is best understood in terms of costs and benefits. Whatever
action of an organism increases thefitness of another organism while decreas-
ing thefitness of itself is altruistic, provided that this behavior is“voluntary”in
the sense of not resulting from extortion or external control. Both parts of this
definition have to be expanded somewhat. First, as we have seen in section 2.1,
fitness in evolution means reproductivefitness, that is, the ability to leave
offspring (that will also leave offspring). If some behavior is both heritable and
increases the organism’sfitness, it will show up in future generations. If some
behavior is heritable and decreases the organism’sfitness, it will be less likely
to be present in future generations. At this point, altruistic behavior seems to
have little chance in evolution. The second part of the definition refers to
altruism being voluntary. This is of course an anthropomorphic concept that
involves the element of“volition,”that is, free will. It is not necessary to go into
the discussion about free will at this point. Let us only note that the voluntary
aspect of altruism does not imply conscious decision-making but simply the
fact that the organism would have had other behavioral options in terms of
external constraints.
Some patterns of cooperation in the animal kingdom make good sense in
terms of a classical Darwinian framework. Let us elaborate somewhat on two
theoretical models introduced in section 2.1. First, the model ofinclusive
fitnessorkin-selection(Hamilton, 1964a, 1964b) applies to cases in which
altruism increases thefitness of a genetically related individual. Here the
decrease in the altruist’s chance of passing on his or her own genes is
compensated for by the sibling’s, cousin’s, or offspring’s increased chance to
pass on genes that are partly identical with those of the altruistic individual.
The genes in question will probably include the ones that underlie altruistic
behavior; consequently, a tendency to altruism will show up in the offspring.
The model ofreciprocal altruism, in turn, applies to cases where the altruist
and the recipient of altruism are not genetically related. In such a case, it
makes sense to increase someone else’s reproductive success if that favor will
be returned later (Trivers, 1971). Note that this model requires that both
parties involved keep record of interactions and avoid helping anyone who
Morality 173