When evolution is discussed in the
media, the same word is often used to name different things. Even
those who are proponents of “evolution” do not always mean the
same thing by the term. As a result, claims are sometimes made
about evolution that purport to be factual, although they have not
been demonstrated scientifically, or do not even belong to the realm
of science.
What is popularly meant by “evolution”
is not only the process by which the many distinct species of living
beings have emerged (speciation), but also the process by which life
itself originated from inanimate matter. Nineteenth-century
naturalist Charles Darwin is widely recognized as the founding father
of evolution, although he really had nothing of substance to suggest
about “evolution” in the latter sense. Following Darwin, the two
principal mechanisms of evolution of new species are generally said
to be random variation and natural selection; in the twentieth
century, scientists have looked especially to changes in an
organism’s genetic code in order to explain, or perhaps to specify,
the notion of random variation.
For the sake of clarity and brevity, we
shall identify three distinct conceptions of evolution that circulate
in the media. These three all share a common origin or inspiration,
but there are also notable differences between them – although
these differences are rarely made explicit by those who talk about
evolution.
Hence, “evolution” might mean
either:
a process, involving random
genetic variations and natural selection, that was and is a driving
force in the development of life on Earth;
or
a process, involving random
genetic variations and natural selection, that provides the
exhaustive explanation for the development of
life on Earth, from the very simplest living organisms all
the way to human beings;
or
a process, involving random
genetic variations and natural selection, that provides the
exhaustive explanation of the existence and nature of all
living beings, including human beings.
Statement #1 is very well established
scientifically. There is plenty of paleontological and biological
evidence to support it, and viruses, for example, are visibly
evolving under our watch.
Statement #2 is at best a hypothetical
statement, and is far from being proven. More than once in the
history of science a theory said to provide a complete or final
explanation of a set of phenomena has later been seen to be
inadequate or even incorrect. Toward the end of the nineteenth
century, for example, it was widely supposed that classical physics
was able to explain, at least in principle, virtually all natural
phenomena, apart from a few presumably unimportant exceptions. But
it was in looking more carefully at these exceptions that scientists
discovered Relativity and Quantum Mechanics, and classical physics no
longer reigned supreme. Philosopher Karl Popper has argued,
moreover, that falsification is the only source of real certainty in
science (i.e., although a given scientific theory is supported by
thousands of successful experiments, they don’t yield absolute
certainty about its truth, whereas a single counterexample does
suffice to show that the theory is wrong or incomplete). Even though
Popper’s position has been criticized for being a bit excessive, it
does correctly remind us that science develops in a tentative
fashion, and that the relatively few categorical claims that it makes
occur, so to say, at the outer edges of its normal activity.
Additionally, in the case of evolution we are very far from
possessing an exhaustive explanation of the development of life on
Earth, despite the enormous strides biology, for example, has made
over the last century.
It is important to recognize, in this
regard, that many scientists have come to think that to explain the
evolution of life on the planet, other mechanisms must be invoked:
gene transfer, neutral mutation, and retroelements/transposons, to
name only a few. Evidence for the existence of such mechanisms
challenges the idea that the set of “variations” from which
nature “selects” new types emerges only randomly, through the
genetic mutations. Evidence has recently been discovered, for
example, that certain epigenetic factors (i.e., factors not specified
by DNA but rather derived from the environment and the organism’s
interaction with it) can be inherited, and this suggests new insights
into the mechanisms of evolution. Developments such as this call
into question the supremacy of the Darwinian view, which proposes to
explain speciation solely through the dual mechanism of “random
mutation and natural selection”. Statement #2, in short, leaves
ample room for scientific reflection, research, and debate.
Statement #3 entirely abandons the
realm of science. Not only does it mistake statement #2 as an
accomplished fact. It also founds itself on the unquestioned
assumption that human life can be reduced entirely to its exclusively
biological components. This conception of human existence is far
from convincing, for there are numerous aspects of human life for
which no credible biological explanation is currently available; nor
is it at all clear how we could even begin to explain them in purely
biochemical terms. What could it possibly mean to encode the human
appetite for justice, truth, beauty, and love, or the self-awareness
that attends them, in some gene or set of genes? Statement #3 simply
assumes, without warrant and with little apparent awareness of what
it ignores, that it is able to account for those dimensions of our
humanity that find profound expression in the most powerful works of
literature and the visual arts, and in the writings of great
philosophers. No doubt, those dimensions of reality of particular
interest to the biologist can have a very palpable impact on even the
most exalted of human activities. One cannot expect a poet in the
midst of an acute attack of appendicitis to compose memorable poetry.
Yet from this it does not follow that the poet’s muse resides in a
small stretch of uninfected appendix.
Author Richard Dawkins offers us a
paradigmatic example of the over-reaching characteristic of certain
exponents of “evolution.” Dawkins writes that “Darwinism
encompasses all of life […]. It provides the only satisfying
explanation for why we all exist, why we are the way that we are.”
While he concedes that “our own existence once presented the
greatest of all mysteries;” he nevertheless insists that “it
is a mystery no longer because it is solved. Darwin and Wallace
solved it.”1 In defense of statement #3, he has
recourse to arguments that purport to be drawn directly from
scientific agreement about statement #1 and from current scientific
debates about statement #2. But the reasoning on display in his work
actually operates at another level entirely, and falls very short of
a scientific demonstration of ”evolution” in the third sense we
have enumerated.
Lacking an adequate scientific
foundation, Darwinism becomes a quasi-philosophical system. When we
read that “Darwinism encompasses all of life” we are reminded of
the great ideologies of the 20th centuries, which made
similar claims to comprehensiveness, with what tragic results we all
know. If random variation and natural selection are the ONLY two
factors governing human life, all kinds of violence against human
beings readily find justification. We see some glimpse of ideological
Darwinism in certain positions on the end of life debate.
We think that a reasonable approach to
reality is one that strives to take all factors into account.
Evolution is a driving force in the development of life on Earth,
nonetheless it does not represent an exhaustive and mechanical
explanation of who we are. Our existence is a mystery. In the words
of Nobel Prize winning physicist Albert Einstein, “One cannot
help but be in awe when contemplating the mysteries of eternity, of
life, of the marvelous structure of reality.”2
Or as another Nobel Prize winner, Richard P. Feynman, put it, “The
same thrill, the same awe and mystery, come again and again when we
look at any problem deeply enough. With more knowledge comes deeper,
more wonderful mystery, luring one to penetrate deeper still.”
3 Both Einstein and Feynman bear witness to the nature
of every truly human initiative – including in a privileged way the
activity of scientific inquiry – all of which express the struggle
to unveil the meaning of reality.
References:
1
R. Dawkins,
introduction (pg X) and preface (pg XIII) of “The
Blind Watchmaker”,
W.W. Norton, ed. 1996.
2
A. Einstein,
statement to William Miller, as quoted in LIFE magazine (2 May 1955).
3
R. P. Feynman,
“The value of
science” in Frontiers
in Science: A Survey,
ed. Edward Hutchings Jr. (New York, 1958), pg 262-63.