Mayr E. What Makes Biology Unique? : Considerations on the Autonomy of a Scientific Discipline
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what makes biology unique?
Chapter 5 – Darwin’sinfluence on modern thought
Charles Darwin contributed many of the concepts on which the paradigm
of modern biology rests. Some of them were controversial for a long time
and are still opposed by certain evolutionists. A full understanding of
the autonomy of biology therefore is not possible without an analysis
of Darwinism. Indeed, modern biology is conceptually Darwinian to a
large extent. Although I attempted in previous publications to charac-
terize this Darwinian contribution to our modern biological thinking,
its importance for the philosophy of biology is so great that this renewed
analysis should be welcome.
Chapter 6 – Darwin’s five theories of evolution
Darwin, throughout his life, referred to his theorizing on evolution as
“my theory,” in the singular. However, it is now quite clear that Darwin’s
evolutionary paradigm consists of five theories, which are independent
of each other. Failing to appreciate this independence unfortunately led
Darwin, and others who followed him, to several misinterpretations.
One will never fully understand the autonomy of biology if one does not
understand the nature of Darwin’s five theories.
Chapter 7 – Maturation of Darwinism
The set of ideas and theories that leading evolutionists now consider
to be the basic components of Darwinism are still remarkably similar
to Darwin’s original proposals in 1859 – largely but not entirely. In
particular, Darwin had not realized that “his theory” [in the singular] is
actually a compound of five different theories. These were accepted by
other evolutionists at different times, with natural selection, after nearly
eighty years of argument, accepted as the last.
The acceptance of evolution is of course a prerequisite for acceptance
of the other four theories. But the validity of each of these four theories
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introduction
is independent of the validity of the other three. One can have a theory
of speciation even if one rejects natural selection or gradualism. Many of
the Darwinian controversies were due to the neglect of the finding that
the validity of each of the four Darwinian theories is largely independent
of the validity of the others.
Chapter 8 – Selection
This theory (or bundle of theories) was, for several reasons, longest re-
sisted. Indeed, our modern concept of this theory differs in a number of
ways from the original Darwinian version. For instance, we now consider
selection more as a process of nonrandom elimination than of positive
selection, and this may facilitate the survival of more and more deviant
variants. Also, we no longer consider variation and elimination simply
as each other’s opposites but are beginning to consider the production of
variety and the succeeding step of elimination as two steps in a single pro-
cess. There remains considerable uncertainty about the role of variation
during the evolutionary process, but there is no argument that selection
is involved in nearly every instance of evolutionary change. A knowledge
of all aspects of selection therefore is basic for a full understanding of
evolution.
Chapter 9 – Do Thomas Kuhn’s scientific revolutions take place?
It is extraordinary how biology has changed in the last two hundred
years: first the establishment of biology as a valid science in the years
from 1828 to 1866, then the Darwinian revolution, then genetics and
the new systematics, and finally the revolution of molecular biology. The
philosopher is deeply interested in the nature of these changes. Were they
gradual or did they occur in a number of scientific revolutions, and if
so what was the nature of these revolutions? One cannot understand the
nature of the currently accepted science of biology unless one understands
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what makes biology unique?
the nature of the conceptual changes of the last two hundred years. In
particular, I attempt to answer in this chapter the question of whether
Kuhn’s concept of scientific revolutions is or is not supported by biology.
Chapter 10 – Another look at the species problem
No matter in what branch of biology one is interested, it is necessary to
work with species. This is the major unit in biogeography, in taxonomy,
and in all comparative branches of biology. Evolution is characterized by
irreversible changes at the species level. Considering this outstanding
importance of the species in biology, it strikes me as almost scandalous
that there is still so much disagreement and uncertainty about almost
every aspect of species. There is no other problem in biology on which
more has been written in recent years and less unity has been achieved
than the species problem. Any discussion of the autonomy of biology
that did not attempt to shed light on the origin and the nature of species
would be incomplete. My own account focuses on the reasons for this
long-standing and seemingly insoluble problem and makes suggestions
for a solution.
Chapter 11 – The origin of humans
It was one of Darwin’s shocking findings that the human species is
not something altogether different from the rest of the living world, as
nearly everybody believed, but instead is part of it – indeed that apes are
the ancestors of humans. Even though this conclusion had already been
made inevitable, on the basis of both comparative biology and the fossil
record, it has now been a thousandfold confirmed by molecular biology.
What is particularly interesting is that by proposing historical narratives
including the life history of our ancestors, it is possible to reconstruct
a rather convincing hominid history. The scenario suggested in this
chapter is based largely on inferences, but they can be tested against
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introduction
a great deal of evidence from fossils and from molecular biology. The
novel historical narrative suggested by me will have to be tested again
and again. However, it has the great advantage that it provides a cohesive
and quite plausible account of the various stages by which a chimpanzee-
like ancestor in the rainforest evolved into Homo sapiens. It is precisely
the autonomous features of biology that make a plausible reconstruction
possible. It produces a solid foundation for the reconstruction of human
history, which a purely physics-based explanation would never be able
to provide.
Chapter 12 – Are we alone in this vast universe?
This question has been asked for more than two thousand years. As an
outgrowth of space research in recent years, a definite research program
has been developed, trying to establish contact with any possible civi-
lizations elsewhere in the universe. Those who have given thought to this
project can readily be assigned to two groups: an optimistic one consist-
ing almost entirely of physical scientists, particularly astronomers. They
are convinced that a search for extraterrestrial intelligence is promis-
ing. By contrast a pessimistic group, consisting mostly of biologists,
has developed a list of reasons why such a search is totally hopeless.
In this chapter, I present the biological reasons, usually neglected by
astronomers, why there is such a low probability of success.
literature cited
Kant, I. 1781. Critique of Pure Reason.
Kitcher, P. 1984. 1953 and all that. Philosophical Reviews, 93:335–373.
Rosenberg, A. 1985. The Structure of Biological Science. Cambridge: Cambridge
University Press.
Ruse, M. 1973. The Philosophy of Biology. London: Hutchinson.
Sober, E. 1993. Philosophy of Biology. Boulder: West View Press.
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Science and Sciences
Biology is a science; there is no argument about this statement,
or is there? Doubts about this claim have been suggested by impor-
tant differences among various widely accepted definitions of science.
A comprehensive, pragmatic definition of science might be “Science is
the human endeavor to achieve a better understanding of the world by
observation, comparison, experiment, analysis, synthesis, and concep-
tualization.” Another definition might be “Science is a body of facts
(‘knowledge’) and the concepts that permit explaining these facts,” and
there are numerous others. In a recent book (Mayr 1997:24–44) I have
devoted a twenty-page chapter to a discussion of the question, “What is
science?”
Difficulties arise because the term science also has been used for so
many human activities beyond the natural sciences, such as the social
sciences, political science, military science, and more distant areas such
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what makes biology unique?
as Marxist science, Western science, feminist science, and even Christian
Science and Creationist Science. In all these combinations, the word
science is used in a misleadingly inclusive sense. Equally misleading,
however, is the opposite extreme, the decision of some physicists and
physicalist philosophers to restrict the word science to mathematically
based physics. A vast literature shows how difficult, indeed impossible, it
seems to be to draw a line between incontrovertible science and adjacent
fields. This diversity is a heritage of history.
One can claim that science originated in preliterary times when people
began to ask “how?” and “why?” questions about the world. Much of
what philosophers were doing in Greece and the Ionian colonies in Asia
Minor and southern Italy was rudimentary science. Aristotle’s work was
a very respectable beginning of the science of biology. However, it is
rather generally accepted that the so-called scientific revolution of the
sixteenth and seventeenth centuries, characterized by Galileo, Descartes,
and Newton, was the real beginning of what is now called science. At that
time most phenomena in the inanimate and the living world were not
yet explained in terms of natural causes, and God was still considered the
ultimate cause of everything. However, in due time secular explanations
were ever more widely adopted and considered legitimate science. It
dealt primarily with two branches of science, mechanics and astronomy.
Not surprisingly, at that time the concept of science was the concept of
these two physical sciences. For Galileo, mechanics was the dominant
science and it remained so for hundreds of years.
When intellectual life revived after the Middle Ages, there was no
word for what we now call science. Indeed, the English word science
for what modern people call science was introduced by Whewell as
late as 1840. However, at the time of the scientific revolution in the
sixteenth, seventeenth, and eighteenth centuries, science was conceived
very broadly by some authors and very narrowly by others.
The philosopher Leibniz was exemplary for the broad conception. For
him and his followers, a “science was a body of doctrine that could
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science and sciences
be known systematically and with a high degree of certainty; it was
contrasted with ‘opinion,’ that which could only be understood with
a lesser degree of certainty, or with ‘art,’ that which involved a prac-
tice rather than doctrine” (Garber and Ariew 1998). Science, thus con-
ceived, included natural sciences, natural history (including medicine,
geology, and chemistry), mathematics, metaphysics and even theological
writings, European history, and linguistics. It is this exceedingly broad
conceptualization of science that is still alive in the German concept
of the Geisteswissenschaften. Everything that in Anglophone countries is
included in the humanities is referred to in the German literature as
Geisteswissenschaften.
This includes the study of classics, philosophy, linguistics, and his-
tory. As a result one recognized in Germany two kinds of Wissenshaften,
the natural sciences and the Geisteswissenschaften. There is indeed some
justification to include some of the cited disciplines of the humanities
among the real sciences. They employ methods and adopt principles that
are analogous to those of the natural sciences. This led to an argument
about where to draw the line between the two kinds of sciences. Con-
sidering how similar evolutionary biology is to historical science and
how different it is from physics in conceptualization and methodology,
it is not surprising that drawing a definite line between the natural sci-
ences and the humanities is so difficult, indeed nearly impossible. For
example, someone might place this line between functional and evolu-
tionary biology, attaching functional biology to the natural sciences and
evolutionary biology to the science of history.
Physicalism
One extreme is Galileo’s(1564–1642) science. At his time only one
science existed, that of mechanics (including astronomy). Hence, when
Galileo characterized science, he based it on his knowledge of mechanics.
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what makes biology unique?
Having no other sciences to compare mechanics with, he did not real-
ize that his characterization of “science” (= mechanics) included two
quite different sets of characteristics – those true for any genuine science
and those true only for mechanics. For instance, he did not realize that
mathematics plays a far greater role in mechanics than in most other
sciences. Hence, mathematics played a dominant role in Galileo’s image
of science. He insisted that the book of nature “cannot be understood
unless one first learns to comprehend the language and read the letters in
which it is composed. It is written in the language of mathematics and
its characters are triangles, circles, and other geometric figures without
which it is humanly impossible to understand a single word of it; with-
out these one wanders about in a dark labyrinth” (Galileo 1632). Nor,
quite naturally, was any discrimination made by anyone else, because
at first there were no other sciences with which to compare mechanics.
Physics with a mathematical foundation became the exemplar of science
for Galileo, Newton, and all the other greats of the Scientific Revolution.
This physicalist interpretation dominated the thinking of the philoso-
phers of science. And this remained so for the next three hundred fifty
years. Curiously, it was quite generally ignored in discussions of science
in those centuries that there were now also other sciences. Instead, these
other sciences were squeezed into the conceptual framework of physics.
Mathematics remained the earmark of true science. Kant certified this
opinion by saying “there is only that much genuine [richtig] science in
any science, as it contains mathematics.” And this greatly exaggerated
evaluation of physics and mathematics has dominated science until the
present day. What would be the scientific status of Darwin’s Origin of
Species (1859), which contains not a single mathematical formula and
only a single phylogenetic diagram (not a geometric figure) if Kant had
been right? And this was also the philosophy of science of the leading
philosophers (e.g., Whewell, Herschel) that affected Darwin’s thought
(Ruse 1979). Yet several recent philosophers of science have published
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science and sciences
a Philosophy of Biology strictly based on the conceptual framework of the
classical physical sciences (e.g., Kitcher 1984, Ruse 1973, Rosenberg
1985) while ignoring the autonomous aspects of biology (chapter 2).
Yes, God was the creator of this world and either directly or through his
laws he was responsible for everything that existed and occurred. Science
for Galileo and his followers was not an alternative to religion but an
inseparable part of it, and this remained true from the sixteenth century
to the first half of the nineteenth century and was accepted by the great
philosophers of that period including Kant. Yet the vigorously expanding
science of the eighteenth and early nineteenth centuries was able to find
a natural explanation for one phenomenon after the other that previously
had required invoking God’s presence. Eventually, only lip service was
paid to Galileo’s claim about the dominant role of mathematics in science.
Even after physicalism was considerably liberalized in the last one hun-
dred years, it remains questionable how sound a basis for a philosophy
of biology it can provide. Historians of physics traditionally have exag-
gerated the importance of the great discoveries in physics in the 1920s
(quantum mechanics, relativity, elementary particle physics, etc.). The
historian Pais said, for instance, that Einstein’s theories “have profoundly
changed the way modern men and woman think about the phenomena of
inanimate nature.” But on second thought he realized his exaggeration
and corrected this claim to “It would actually be better to say ‘modern
scientists’ than ‘modern men and women.’” Actually, it would be even
better to say “physical scientists,” because Einstein’s theories did not
affect other scientists at all. Indeed, to appreciate Einstein’s contribu-
tions in their fullness, one needs to be schooled in the physicist’s style
of thinking and in special branches of mathematics. It requires much
optimism to guess that even one in every 100,000 humans alive today
has any insight into what Einstein’s relativity is all about. Indeed, hardly
any of the great discoveries in physics in the 1920s had any apparent
effect on biology at all.
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