December 4, 2000
Understanding Human Natures
Arri Eisen is a senior
lecturer in biology and director of the
Emory College Program in Science and Society.
Is it possible that teaching evolution might help prevent racist incidents or the overuse of antibiotics? That an understanding of biologic and cultural co-evolution can help humanity address some of its deepest problems?
In his ambitious Human Natures, Paul Ehrlich, a leading thinker
in the field of evolutionary biology for nearly 40 years, makes provocative
arguments supporting such claims.
Heres a reflective book in which an elder statesman sits back and
tries to figure it all out. Ehrlich does an impressive job of it. He joins
the ranks of Stephen J. Gould, Steven Pinker and Richard Dawkins as great
synthesizers of ideas and information on evolution.
Imagine addressing questions like: Why do we walk upright? What are language
and consciousness and how did they evolve? Why do we go to war?
From cavemen to Columbine, Ehrlich takes on this enormous task with an
effective and informal writing style andwith an excellent background
on genetics and evolutionmakes Human Natures accessible to a general
audience and enjoyable to read.
Ehrlichs central thesis is that each of us has a unique human nature; there is not one singular human nature. Ehrlich argues that, for example, saying aggressiveness or going to war is just human nature has dangerous implications (analogous to excusing a particular behavior because someone has the gene for it) and is plain wrong.
Each of us has some chance of making rude gestures at the car that wouldnt
let us into the next lane or bashing our brothers in the face when they
wont share. That chance, thoughand this is the essential pointdepends
on our unique combination of genetic predispositions which have been strongly
shaped by our environment: culture, experience, language, geography, social
grouping. All this together composes our distinct human natures.
Maybe its just my nature, but I am much more drawn to Ehrlichs
synthesis of how we become who we are than to the selfish gene
ideas of Dawkins.
Dawkins and his followers say, basically, that everything can be explained
by whats best for the genes; we are merely a convenient means for
the genes to get themselves passed on to the next generation.
Ehrlich builds a strong case for his more reasonable assertion that what
we become is a combination of genes and culturea co-evolution between
the two. And it is culture, Ehrlich argues, that is the dominant component
in this equation.
A significant portion of Human Natures examines how an understanding
of evolution and our evolutionary history is useful for helping productively
approach major societal problems. For example, the evolution of our minds
was driven by vision. If all the junk we dumped into the air turned the
sky green, we probably would have cleaned it up long ago. Most of our
biologic evolution took place in social groups of 100 or so; now most
of us live with millions.
Cultural evolution can happen much faster than biologic evolution. Our
ability to do has far outpaced our ability to understand what we are doing
and its implications. But all is not lost. Human beings are uniquely able
to carry out what Ehrlich calls conscious evolution. Using
as one example the scientific communitys response to the threat
of nuclear war, Ehrlich posits that we can intentionally change our evolution.
This view and most others expressed in the book are less reductionist,
more humanist, than those expressed by many evolutionary biologists. Not
surprisingly then, Ehrlich criticizes the cultural evolution of our universitiesthe
places we turn to for answers to societys problemsinto disciplinary
At Emory, we encourage interdisciplinary approaches to problems as significant
and important enterprises in the academic arena. Ehrlich says such approaches
are necessary for the survival of our civilization. Diverse scholars must
share perspectives and bring substantial conversation to the public on
issues such as environmental sustainability, genetic engineering and population
Ehrlich reinforces Ernst Mayrs claim that Charles Darwin had more
influence on science and human thought than perhaps any other individual
of the last century.
When I told a friend about Human Natures, he groaned and said, Look, evolutions great, the foundation of biology, but why do people feel it necessary to use it to explain everything? I told him the desire among people, especially when theyre older, to synthesize and understand the world is probably, at least for some, human nature.