Evolution cannot explain moral behavior, especially altruism.
Evolutionary fitness is selfish; individuals win only by benefitting
themselves and their offspring.
The claim ignores what happens when organisms live socially. In fact,
much about morals can be explained by evolution. Since humans are
social animals and they benefit from interactions with others, natural
selection should favor behavior that allows us to better get along with
others.
Fairness and cooperation have value for dealing with people repeatedly
(Nowak et al. 2000). The emotions involved with such justice could
have evolved when humans lived in small groups (Sigmund et al. 2002).
Optional participation can foil even anonymous exploitation and make
cooperation advantageous in large groups (Hauert et al. 2002).
Kin selection can explain some altruistic behavior toward close
relatives; because they share many of the same genes, helping them
benefits the giver's genes, too. In societies, altruism benefits the
giver because when others see someone acting altruistically, they are
more likely to give to that person (Wedekind and Milinski 2000). In
the long term, the generous person benefits from an improved reputation
(Wedekind and Braithwaite 2002). Altruistic punishment (punishing
another even at cost to yourself) allows cooperation to flourish even
in groups of unrelated strangers; the abstract of Fehr and Gächter
(2002) is worth quoting in full:
Human cooperation is an evolutionary puzzle. Unlike other creatures,
people frequently cooperate with genetically unrelated strangers,
often in large groups, with people they will never meet again, and
when reputation gains are small or absent. These patterns of
cooperation cannot be explained by the nepotistic motives associated
with the evolutionary theory of kin selection and the selfish
motives associated with signalling theory or the theory of
reciprocal altruism. Here we show experimentally that the altruistic
punishment of defectors is a key motive for the explanation of
cooperation. Altruistic punishment means that individuals punish,
although the punishment is costly for them and yields no material
gain. We show that cooperation flourishes if altruistic punishment
is possible, and breaks down if it is ruled out. The evidence
indicates that negative emotions towards defectors are the proximate
mechanism behind altruistic punishment. These results suggest that
future study of the evolution of human cooperation should include a
strong focus on explaining altruistic punishment.
Finally, evolution does not require that all traits be adaptive 100
percent of the time. The altruism that benefits oneself most of the
time may contribute to life-risking behavior in some infrequent
circumstances.
This claim is an argument from incredulity. Not
knowing an
explanation does not mean no explanation exists. And as noted above,
much of the explanation is known already.
References:
Fehr, Ernst and Simon Gächter, 2002. Altruistic punishment
in humans. Nature 415: 137-140.
Hauert, C., S. De Monte, J. Hofbauer and K. Sigmund, 2002.
Volunteering as Red Queen mechanism for cooperation in public goods
games. Science 296: 1129-1132.
Nowak, M. A., K. M. Page and K. Sigmund, 2000. Fairness versus reason
in the ultimatum game. Science 289: 1773-1775.
Sigmund, Karl, E. Fehr and M. A. Nowak, 2002. (see below)
Wedekind, C. and V. A. Braithwaite, 2002. The long-term benefits of
human generosity in indirect reciprocity. Current Biology 12:
1012-1015.
Wedekind, C. and M. Milinski, 2000. Cooperation through image scoring
in humans. Science 288: 850-852. See also Nowak, M. A. and K.
Sigmund, 2000. Shrewd investments. Science 288: 819-820.
