The Biological Basis of Morality
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CENTURIES of debate on the origin of ethics
come down to this: Either ethical principles, such
as justice and human rights, are independent of
human experience, or they are human inventions.
The distinction is more than an exercise for
academic philosophers. The choice between these
two understandings makes all the difference in
the way we view ourselves as a species. It
measures the authority of religion, and it
determines the conduct of moral reasoning.
The two assumptions in competition are like islands in a sea of chaos, as
different as life and death, matter and the void. One cannot learn which
is correct by pure logic; the answer will eventually be reached through
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Do we invent our moral absolutes in order to make society workable? Or
are these enduring principles expressed to us by some transcendent or
Godlike authority? Efforts to resolve this conundrum have perplexed,
sometimes inflamed, our best minds for centuries, but the natural
sciences are telling us more and more about the choices we make and
our reasons for making them
EDWARD O. WILSONEDWARD O. WILSON APRIL 1998APRIL 1998 ISSUE ISSUE
an accumulation of objective evidence. Moral reasoning, I believe, is at
every level intrinsically consilient with — compatible with, intertwined
with — the natural sciences. (I use a form of the word “consilience” —
literally a “jumping together” of knowledge as a result of the linking of
facts and fact-based theory across disciplines to create a common
groundwork of explanation — because its rarity has preserved its
precision.)
Every thoughtful person has an opinion on which premise is correct. But
the split is not, as popularly supposed, between religious believers and
secularists. It is between transcendentalists, who think that moral
guidelines exist outside the human mind, and empiricists, who think
them contrivances of the mind. In simplest terms, the options are as
follows: I believe in the independence of moral values, whether from
God or not, and I believe that moral values come from human beings
alone, whether or not God exists.
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Theologians and philosophers have almost always focused on
transcendentalism as the means to validate ethics. They seek the grail of
natural law, which comprises freestanding principles of moral conduct
immune to doubt and compromise. Christian theologians, following
Saint Thomas Aquinas’s reasoning in Summa Theologiae, by and large
consider natural law to be an expression of God’s will. In this view,
human beings have an obligation to discover the law by diligent
reasoning and to weave it into the routine of their daily lives. Secular
philosophers of a transcendental bent may seem to be radically different
from theologians, but they are actually quite similar, at least in moral
reasoning. They tend to view natural law as a set of principles so
powerful, whatever their origin, as to be self-evident to any rational
person. In short, transcendental views are fundamentally the same
whether God is invoked or not.
For example, when Thomas Jefferson, following John Locke, derived the
doctrine of natural rights from natural law, he was more concerned with
the power of transcendental statements than with their origin, divine or
secular. In the Declaration of Independence he blended secular and
religious presumptions in one transcendentalist sentence, thus deftly
covering all bets: “We hold these Truths to be self-evident, that all Men
are created equal, that they are endowed by their Creator with certain
unalienable Rights, that among these are Life, Liberty, and the Pursuit
of Happiness.” That assertion became the cardinal premise of America’s
civil religion, the righteous sword wielded by Abraham Lincoln and
Martin Luther King Jr., and it endures as the central ethic binding
together the diverse peoples of the United States.
So compelling are such fruits of natural-law theory, especially when the
Deity is also invoked, that they may seem to place the transcendentalist
assumption beyond question. But to its noble successes must be added
appalling failures. It has been perverted many times in the past — used,
for example, to argue passionately for colonial conquest, slavery, and
genocide. Nor was any great war ever fought without each side thinking
its cause transcendentally sacred in some manner or other.
So perhaps we need to take empiricism more seriously. In the empiricist
view, ethics is conduct favored consistently enough throughout a society
to be expressed as a code of principles. It reaches its precise form in
each culture according to historical circumstance. The codes, whether
adjudged good or evil by outsiders, play an important role in
determining which cultures flourish and which decline.
The crux of the empiricist view is its emphasis on objective knowledge.
Because the success of an ethical code depends on how wisely it
interprets moral sentiments, those who frame one should know how the
brain works, and how the mind develops. The success of ethics also
depends on how accurately a society can predict the consequences of
particular actions as opposed to others, especially in cases of moral
ambiguity.
The empiricist argument holds that if we explore the biological roots of
moral behavior, and explain their material origins and biases, we should
be able to fashion a wise and enduring ethical consensus. The current
expansion of scientific inquiry into the deeper processes of human
thought makes this venture feasible.
The choice between transcendentalism and empiricism will be the
coming century’s version of the struggle for men’s souls. Moral
reasoning will either remain centered in idioms of theology and
philosophy, where it is now, or shift toward science-based material
analysis. Where it settles will depend on which world view is proved
correct, or at least which is more widely perceived to be correct.
Ethicists, scholars who specialize in moral reasoning, tend not to declare
themselves on the foundations of ethics, or to admit fallibility. Rarely do
we see an argument that opens with the simple statement This is my
starting point, and it could be wrong. Ethicists instead favor a fretful
passage from the particular to the ambiguous, or the reverse —
vagueness into hard cases. I suspect that almost all are
transcendentalists at heart, but they rarely say so in simple declarative
sentences. One cannot blame them very much; explaining the ineffable
is difficult.
I am an empiricist. On religion I lean toward deism, but consider its
proof largely a problem in astrophysics. The existence of a God who
created the universe (as envisioned by deism) is possible, and the
question may eventually be settled, perhaps by forms of material
evidence not yet imagined. Or the matter may be forever beyond human
reach. In contrast, and of far greater importance to humanity, the idea
of a biological God, one who directs organic evolution and intervenes in
human affairs (as envisioned by theism), is increasingly contravened by
biology and the brain sciences.
The same evidence, I believe, favors a purely material origin of ethics,
and it meets the criterion of consilience: causal explanations of brain
activity and evolution, while imperfect, already cover most facts known
about behavior we term “moral.” Although this conception is relativistic
(in other words, dependent on personal viewpoint), it can, if evolved
carefully, lead more directly and safely to stable moral codes than can
transcendentalism, which is also, when one thinks about it, ultimately
relativistic.
Of course, lest I forget, I may be wrong.
Transcendentalism Versus Empiricism
THE argument of the empiricist has roots that go back to Aristotle’s
Nicomachean Ethics and, in the beginning of the modern era, to David
Hume’s A Treatise of Human Nature (1739-1740). The first clear
evolutionary elaboration of it was by Charles Darwin, in The Descent of
Man (1871).
Again, religious transcendentalism is bolstered by secular
transcendentalism, to which it is fundamentally similar. Immanuel
Kant, judged by history the greatest of secular philosophers, addressed
moral reasoning very much as a theologian. Human beings, he argued,
are independent moral agents with a wholly free will, capable of obeying
or breaking moral law: “There is in man a power of self-determination,
independent of any coercion through sensuous impulses.” Our minds
are subject to a categorical imperative, Kant said, of what our actions
ought to be. The imperative is a good in itself alone, apart from all other
considerations, and it can be recognized by this rule: “Act only on that
maxim you wish will become a universal law.” Most important, and
transcendental, ought has no place in nature. Nature, Kant said, is a
system of cause and effect, whereas moral choice is a matter of free will,
absent cause and effect. In making moral choices, in rising above mere
instinct, human beings transcend the realm of nature and enter a realm
of freedom that belongs exclusively to them as rational creatures.
Now, this formulation has a comforting feel to it, but it makes no sense
at all in terms of either material or imaginable entities, which is why
Kant, even apart from his tortured prose, is so hard to understand.
Sometimes a concept is baffling not because it is profound but because it
is wrong. This idea does not accord, we know now, with the evidence of
how the brain works.
In Principia Ethica (1903), G. E. Moore, the founder of modern ethical
philosophy, essentially agreed with Kant. In his view, moral reasoning
cannot dip into psychology and the social sciences in order to locate
ethical principles, because those disciplines yield only a causal picture
and fail to illuminate the basis of moral justification. So to reach the
normative ought by way of the factual is is to commit a basic error of
logic, which Moore called the naturalistic fallacy. John Rawls, in A
Theory of Justice (1971), once again traveled the transcendental road.
He offered the very plausible suggestion that justice be defined as
fairness, which is to be accepted as an intrinsic good. It is the imperative
we would follow if we had no starting information about our own future
status in life. But in making such a suggestion Rawls ventured no
thought on where the human brain comes from or how it works. He
