Biological and Cultural Evolution
as Components of Ethical Behavior
Francisco J. Ayala
University of California, Irvine
Charles Darwin
The Descent of Man, and Selection in Relation to Sex
We must acknowledge, as it seems to me, that man
with all his noble qualities, with sympathy which feels
for the most debased, with benevolence which
extends not only to other men but to the humblest
living creature, with his god-like intellect which has
penetrated into the movements and constitution of
the solar system—with all these exalted powers—
Man still bears in his bodily frame the indelible stamp of his
lowly origin.
Metaethics: Why we ought to do what we ought to do.
Normative ethics: What we ought to do.
Practical ethics: Moral norms applied to particular
situations.
Metaethical Doctrines
Moral realism: There are moral facts. Our moral
judgments are made true or false by the moral facts.
Divine command: God’s commanding is what makes a
particular action moral.
Utilitarianism: Does the most expected good to the
largest number of people.
Positivism: No rational foundations for morality.
Emotional decisions or social agreement.
Libertarianism: Maximize personal freedom.
St. Thomas Aquinas:
Three components of moral law
Divine command
e.g., Worship only one God
Love your neighbor
Natural law
e.g., Don’t kill
Don’t commit adultery
Civil authority
e.g., Respect private property
Pay taxes
Evolutionary ethics:
Herbert Spencer
Julian Huxley
C.H. Waddington
E.O. Wilson: Sociobiology
Evolutionary psychology
Evolutionary ethics:
Herbert Spencer: Social Darwinism
Struggle for existence determines evolutionary progress
Moral law = Struggle for existence
Critique (Thomas Huxley): Naturalistic fallacy
Identifying what “is” with what “ought to be”
(D. Hume, 1740; G.E. Moore, 1903)
Evolutionary ethics:
Julian Huxley, Evolution and Ethics, 1947
C.H. Waddington, The Ethical Animal, 1960
Evolutionary ethics:
Sociobiology. On Human Nature, 1977
Evolutionary psychology
An animal with well-defined social instincts
—like parental and filial affections—‘‘would
inevitably acquire a moral sense or conscience,
as soon as its intellectual powers had become
as well, or nearly as well developed, as in
man.’’
Darwin, Descent of Man
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 the same moral
sense as ours. . . . [T]hey might have a sense of
right and wrong, though led by it to follow
widely different lines of conduct.
Darwin, Descent of Man
Ethics
1.
2.
Capacity for ethics (evaluating
actions as good or evil)
Codes of ethics (norms by
which we judge a particular
action)
Ethics
1.
2.
Capacity for ethics
(evaluating actions
as good or evil)
Codes of ethics
(norms by which
we judge a
particular action)
Language
1.
2.
Capacity for
symbolic verbal
communication
Particular
languages:
English, Spanish,
Arabic, …
Capacity for ethics
(evaluating actions as good or evil)
1. Ability
to anticipate the
consequences of one’s actions
2. Ability to make value judgments
3. Ability to choose between
alternative courses of action
Capacity for ethics
(evaluating actions as good or evil)
1. Ability
to anticipate the
consequences of one’s actions
Bipedal
Gait
Tool
Making
Enlarged
Brain
Capacity for ethics
(evaluating actions as good or evil)
1. Ability
to anticipate the
consequences of one’s actions
2. Ability to make value judgments
Capacity for ethics
(evaluating actions as good or evil)
1. Ability
to anticipate the
consequences of one’s actions
2. Ability to make value judgments
3. Ability to choose between
alternative courses of action
Ethics
1.
2.
Capacity for ethics (evaluating
actions as good or evil)
Codes of ethics (norms by
which we judge a particular
action)
Ethics
1.
2.
Capacity for ethics
(evaluating actions
as good or evil)
Codes of ethics
(norms by which
we judge a
particular action)
Language
1.
2.
Capacity for
symbolic verbal
communication
Particular
languages:
English, Spanish,
Arabic, …
Codes of ethics (norms by which
we judge a particular action):
Cultural evolution
Heredity + Variation + Differential
reproduction (natural selection) =
Evolution
Codes of ethics (norms by which we
judge a particular action):
Variation among individuals
Variation among groups
Variation from one to another time
Codes of ethics:

Cultural selection: imitation, learning,
assimilation
Example: monotheism
Moses and the Ten Commandments
Enforced by civil authority
Reinforced by divine authority
Cultural evolution: vastly more efficient means
of adaptation than biological evolution.

More rapid. Potentially to all mankind in less than
one generation.

Directed mutations (inventions and discoveries),
which occur at high frequency.

Cumulative. Adaptations added without
replacement.

Group selection. Humans take into account the
benefits to the group (because it also benefits them).
Conclusions
Capacity of ethics: Biological evolution
Codes of ethics: Cultural evolution
(including religion)
Darwin’s Moral Optimism:
There can be no doubt that a tribe including many
members who, from possessing in a high degree the spirit
of patriotism, fidelity, obedience, courage, and sympathy,
were always ready to give aid to each other and to
sacrifice themselves for the common good, would be
victorious over most other tribes; and this would be
natural selection. At all times throughout the world
tribes have supplanted other tribes; and as morality is
one element in their success, the standard of morality
and the number of well-endowed men will thus
everywhere tend to rise and increase.
Darwin, Descent of Man
Thank you!