built on experiment and
observation, can possibly extend to; and willingly left, to more presumptuous
inquirers, the task of carrying their reasonings beyond the boundaries of nature.
Finally, to Kirwan's charge that Hutton had limited science
by his "evasion" of origins, Playfair responded that his friend had
strengthened science by his positive program of studying what could be resolved:
Instead of an evasion, therefore, any one who considers the subject fairly, will
see, in Dr. Hutton's reasoning, nothing but the caution of a philosopher, who
wisely confines his theory within the same limits by which nature has confined
his experience and observation.
This all happened a long
time ago and in a context foreign to our concerns. But Hutton's methodological
wisdom, and Playfair's eloquent warning, could not be more relevant today--for
basic principles of empirical science do have an underlying generality that can
transcend time. Practicing scientists have largely (but not always) imbibed Hutton's
wisdom about restricting inquiry to questions that can be answered. But Kirwan's
error of equating the best in science with the biggest questions about ultimate
things continues to be the most common of popular misunderstandings.
I have often mentioned that fifteen years of monthly columns have brought
me an enormous correspondence from nonprofessionals about all aspects of science.
From sheer volume, I obtain a pretty good sense of strengths and weaknesses in
public perceptions. I have found that one common misconception surpasses all others.
People will write, telling me that they have developed a revolutionary theory,
one that will expand the boundaries of science. These theories, usually described
in several pages of single-spaced typescript, are speculations about the deepest
ultimate questions we can ask--what is the nature of life? the origin of the
universe? the beginning of time?
But thoughts are cheap.
Any person of intelligence can devise his half dozen before breakfast. Scientists
can also spin out ideas about ultimates. We don't (or, rather, we confine them
to our private thoughts) because we cannot devise ways to test them, to decide
whether they are right or wrong. What good to science is a lovely idea that cannot,
as a matter of principle, ever be affirmed or denied?
following homily may seem paradoxical but it embodies Hutton's wisdom: the best
science often proceeds by putting aside the overarching generality and focusing
instead on a smaller question that can be reliably answered. In so doing, scientists
show their intuitive feel for the fruitful, not their narrowness or paltriness
of spirit. In this way we sneak up on big questions that only repel us if we try
to engulf them in one fell speculation. Newton could not discover the nature of
gravity, but he could devise a mathematics that unified the motion of a carriage
with the revolution of the moon. Darwin never tried to grasp the meaning of life
(or even the manner of its origin on our planet), but he did develop a powerful
theory to explain its manner of change through time. Hutton did not discover how
our earth originated, but he developed some powerful and testable ideas about
how it ticked. You might almost define a good scientist as a person with the horse
sense to discern the largest answerable question--and to shun useless issues
that sound bigger
Hutton's positive principle of restriction
to the doable also defines the domain and procedures of evolutionary biology,
my own discipline. Evolution is not the study of life's ultimate origin as a path
toward discerning its deepest meaning. Evolution, in fact, is not the study of
origins at all. Even the more restricted (and scientifically permissible) question
of life's origin on our earth lies outside its domain. (This interesting problem,
I suspect, falls primarily within the purview of chemistry and the physics of
self-organizing systems.) Evolution studies the pathways and mechanisms of organic
change following the origin of life. Not exactly a shabby subject either--what
with such resolvable questions as "how, when, and where did humans evolve?";
"how do mass extinction, continental drift, competition among species, climatic
change, and inherited constraints of form and development interact to influence
the manner and rate of evolutionary change?"; "how do the branches of
life's tree fit together?" to mention just a few among thousands equally
In their recently aborted struggle to inject
Genesis literalism into science classrooms, fundamentalist groups followed their
usual opportunistic strategy of arguing two contradictory sides of a question
when a supposed rhetorical advantage could be extracted from each. Their main
pseudoargument held that Genesis literalism is not religion at all, but really
an alternative form of science (creation science) not acknowledged by professional
biologists too hidebound and dogmatic to appreciate the cutting edge of their
own discipline. When we successfully pointed out that creation science--as
an untestable set of dogmatic proposals--could not qualify as science by any
standard definition, they turned around and shamelessly argued the other side.
(They actually pulled off the neater trick of holding both positions simultaneously.)
Now they argued that, yes indeed, creation science is religion, but evolution
is equally religious.
To support this dubious claim,
they tumbled (as a conscious trick of rhetoric, I suspect) right into Kirwan's
error. They ignored what evolutionists actually do and misrepresented our science
as the study of life's ultimate origin. They then pointed out, as Hutton had,
that questions of ultimate origins are not resolvable by science. Thus, they claimed,
creation science and evolution science are symmetrical--that is, equally religious.
Creation science isn't science because it rests upon the untestable fashioning
of life ex nihilo by God. Evolution science isn't science because it tries, as
its major aim, to resolve the unresolvable and ultimate origin of life. But we
do no such thing. We understand Hutton's wisdom--"he has nowhere treated
of the first origin... of any substance... but only of the transformations which
bodies have undergone..."
Our legal battle with
creationists started in the 1920s and reached an early climax with the conviction
of John Scopes in 1925. After some quiescence, it began in earnest again during
the 1970s and has haunted us ever since. (I have written more than half a dozen
essays, most in this series, on the resurgence of creation science.) Finally,
in June 1987, the Supreme Court ended this major chapter in American history with
a decisive 7-2 vote, striking down the last creationist statute, the Louisiana
equal time act, as a ruse to inject religion into science classroom in violation
of first amendment guarantees for separation of church and state.
I don't mean to appear ungrateful, but we fallible humans are always seeking
perfection in others. I couldn't help wondering how two justices could have ruled
the other way. I may not be politically astute, but I am not totally naive either.
I have read Justice Scalia's long dissent carefully, and I recognize that its
main thrust lies in legal issues supporting the extreme judicial conservatism
espoused by Scalia and the other dissenter, Chief Justice Rehnquist. Nonetheless,
though it may form only part of his rationale, Scalia's argument relies crucially
upon a false concept of science--Kirwan's error again. I regret to say that
Justice Scalia does not understand the subject matter of evolutionary biology.
He has simply adopted the creationists' definition and thereby repeated their
Justice Scalia writes, in his key statement
on scientific evidence.
NATURAL HISTORY 10/87