INTRODUCTION
TO THE PHILOSOPHY OF
SCIENCE
A Text by Members of the Department of the
History and Philosophy of Science of the University
of Pittsburgh
Merrilee H. Salmon. ' John Barman • Clark Glymour James G. Lennox
• Peter Machamer • J. E. McGuire John D. Norton • Wesley C. Salmon
• Kenneth F. Schaffner
PRENTICE HALL
Englewood Cliffs, New Jersey 07632
CONTENTS
PREFACE
1
INTRODUCTION
PART ONE: GENERAL TOPICS IN THE PHILOSOPHY OF SCIENCE
1 SCIENTIFIC EXPLANATION
(W. Salmon)
7
2 THE CONFIRMATION OF SCIENTIFIC HYPOTHESES (J.EARMAN, W. Salmon)
42
3
REALISM AND
THE NATURE OF THEORIES
(Clark Glymour)
104
(• J. E. McGuire) 132
4 SCIENTIFIC CHANGE: PERSPECTIVES AND PROPOSALS
PART TWO: PHILOSOPHY OF THE PHYSICAL SCIENCES
5 PHILOSOPHY OF SPACE AND TIME
- (John D. Norton)
179
6. DETERMINISM IN THE PHYSICAL SCIENCES
7
(J.EARMAN)
232
PART THREE: PHILOSOPHY OF BIOLOGY AND MEDICINE
(James G. Lennox)
269
PHILOSOPHY OF BIOLOGY
8 Philosophy OF medicine
(Kenneth F. Schaffner)
310
PART FOUR: PHILOSOPHY OF
BEHAVIORAL AND SOCIAL SCIENCES
9 PHILOSOPHY OF PSYCHOLOGY (Peter Machamer)
346
10
android epistemology: computation, artificial intelligence, AND THE
PHILOSOPHY OF SCIENCE
(Clark Glymour)
364
11
PHILOSOPHY OF THE SOCIAL SCIENCES
(Merrilee H. Salmon)
404
BIBLIOGRAPHY
INDEX
426
447
INTRODUCTION
Scientific knowledge stands as the supreme intellectual achievement of our society. Governments, private
foundations, and businesses support scientific research although it is costly and does not always yield immediate
practical benefits. Courses in science are a required part of curricula from grade school through university, and
young people are encouraged to undergo the long apprenticeship of study and work that will transform them into
scientists. Scientific accomplishments are honored at every level, from awards at local science fairs to Nobel
prizes. Major museums in cities all over the western world document and display scientific achievements and
inventions. Yet despite the impressive scope of scientific progress and all the attention paid to science and
scientists, many questions remain about the nature of science and how it works.
Such questions are not usually raised in the study of specific sciences. Physics is concerned, for example, with
providing explanations of why chain reactions occur in certain kinds of materials but not in others; it is not the
task of physics to outline an answer to the more general question of what features an explanation must have if it
is to be scientifically acceptable. Biologists study populations of fruit flies to draw conclusions about how
heredity works. They do not, as biologists, address in a general way the issue of the nature of the relationship
between observation and theories. This is not to say that physicists and biologists are incapable of discussing such
topics or of clarifying them. When they do so, however, they are speaking philosophically about science rather
than actually doing science.
"Philosophy of science" is the name given to that branch of philosophy that reflects on and critically analyzes
science. As a discipline, it tries to understand the aims and methods of science, along with its principles,
practices, and achievements. Philosophers try to provide precise answers to very broad questions about science,
such as the question just raised about the nature of scientific explanation. Some other
questions studied by philosophers of science are as follows:
What are the aims of science?
What is the role of observations and experiments in obtaining scientific knowledge?
How do scientists justify their claims? What is a scientific proof? What is a
scientific law?
Arc there methods for making scientific discoveries? How does scientific knowledge
advance and grow? How do the historical and cultural settings in which scientific
work occurs affect
the content and quality of such work? Does science
employ or require a special language?
Science itself is made up of many subdisciplines: physics, astronomy, chemistry, biology,
psychology, sociology, anthropology, and medicine, to name a few. The presence of so
many different fields within science raises interesting questions about what it means to be
a science and whether a single method is common to all sciences. Philosophy of science
thus addresses also the following sorts of questions:
Is it possible to give a general account of scientific methodology, or are there
different methods and forms of explanation for various branches of science? How
do physical, biological, and social sciences differ from one another? Can some
sciences be reduced to others?
Finally, philosophy of science is concerned with specific issues that arise in
connection with particular fields of science. For example, while experimentation plays a
major role in some sciences, in others, such as astronomy, it does not. Some other
discipline-specific questions are these;
Does the existence of free will pose a special problem for a science of human
behavior?
Is medicine more an art than a science? Are statistical techniques useful in
anthropology, where sample sizes are very
small?
All of the questions raised above are complex and difficult, so it should come as no
surprise that the opinions of philosophers of science (and scientists in their philosophical
moments) on these topics vary considerably. In the twentieth century, two disparate
approaches have been dominant. The earlier tradition, developed by logical positivists
(members of the Vienna Circle) and logical empiricists (a similar group from Berlin), set
rigorous standards for the conduct of philosophy of science, as close to those of science
itself as the subject matter would allow. These philosophers and scientists attempted to
provide logical analyses of the nature of scientific
2
Introduction
concepts, the relation between evidence and theory, and the nature of scientific
explanation. In their desire to be precise, they made extensive use of the language and
techniques of symbolic logic. Despite many differences in points of view, the logical
positivists and logical empiricists generally were concerned with emphasizing such
distinctions as
the demarcation between scientific knowledge and other types of knowledge,
the difference between facts and values,
the difference between the language used to state observations and that used to
refer to theoretical entities, and the difference between how theories are discovered
and how they are justified.
Logical empiricists and logical positivists were also concerned with establishing clear
meanings for all the terms used in science. Some approached this problem by searching
for a verifiability criterion of meaning while others, particularly scientists themselves,
tried to formulate operational definitions of scientific terms. These efforts were closely
related to their concern with providing a solid foundation for scientific theorizing by
linking it firmly to an observational basis. Although they believed that justification rather
than discovery was the proper concern of science, they shared an optimism about the
ability of science to provide genuine knowledge of the features of an independently
existing world.
At the time of World War Two, many of these philosophers left Europe for England
and the United States where their works have significantly affected the development of
philosophy of science in English-speaking countries. Even at the level of undergraduate
education, their influence has been important. Carl G. Hempel, who came to America
from Berlin, for example, has literally defined the philosophy of the natural sciences for
generations of students who first learned about the subject from his introductory text,
Philosophy of Natural Science (1966). The power and broad influence of the general
approach outlined by Hempel in this work justifies calling it "the standard view" of
philosophy of science.
During the past twenty-five years, however, many criticisms have been raised
against perceived faults of the standard view. (Indeed, Hempel himself has criticized some
of its features.) A major objection is that the standard view fails to take account of the
bearing of history of science on the philosophy of science. Critics of the standard view
cite Thomas Kuhn's Structure of Scientific Revolutions (1962, 1970), which argues that
most scientific textbooks ignore history and distort the real nature of progress in science
by presenting it as a series of accumulations of new discoveries that straightforwardly
build on and add to knowledge already attained. Kuhn draws attention to the revolutionary
character of science—its replacement of outworn theories by newer ones that are so
different from the old that the two do not share the same problems or even a common
language. He also draws attention to the "irrational" aspects of changes in science, that is
to say, those features of scientific change that cannot be accounted for entirely in terms of
scientists' allegiance to "facts" and logic- Kuhn argues that only a refusal to take seriously
the history of science could account for the gross distortion presented in scientific
textbooks.
Introduction
3
Appealing to Kuhn's account of science, critics of the standard view of philosophy of
science say that it embodies and promotes an ahistorical view of scientific activity by
emphasizing the logical characteristics of science while ignoring the
” cultural context of scientific activity, which strongly influences the style of the enterprise
and the content of its results. Furthermore, critics say, failure to take account of the
rhetorical features of scientific discourse can only lead to a distorted notion of how science
really works. The values of society and of individual practitioners of science, they say,
influence not only the choice of problems and the amount of effort devoted to their
solution, but also the interpretation of the results. They maintain that so-called facts can
only be grasped through theories, which are the creations of members of a specific culture,
and are never completely free of the values and aspirations of that culture.
Both the standard view and that of its critics have merits and shortcomings. Both views are
likewise too complex to state succinctly without distortion and oversimplification; the
above brief synopsis is intended only to introduce the reader to the subject. The ensuing
chapters will survey many aspects of the dispute and will examine the reasons offered in
support of the various positions.
The approach to the philosophy of science exemplified in this work does not fall
neatly into either of the two main categories briefly outlined. The authors of this text are all
members of a Department of History and Philosophy of Science. The marriage
I between history and philosophy in the Department is not merely one of convenience
between philosophers and historians each of whom happens to be concerned with science.
Instead, the Department was founded because the members believe that the study of the
philosophy of science must be informed by an understanding of the
' historical and social context of science, as well as by a grasp of the workings of science
itself. At the same time, the general approach of this book disavows the extreme forms of
relativism and skepticism that characterize some of the more strident critics of the
standard view.
-' Part One of this book takes up topics requisite for any adequate introduction to the
philosophy of science: Explanation; Induction and Confirmation; Realism and the t Nature of
Scientific Theories: and Scientific Change: Perspectives and Proposals.
'' These four chapters outline and discuss fundamental issues in philosophy of science and
form the foundation for discussions in the remaining chapters of the book. In Part One,
the reader is introduced to the pertinent history of the topics discussed as well as to the
vocabulary, techniques, and most important issues in contemporary philosophy of science.
The intention of the authors in each case is to presume no prior knowledge of philosophy
of science, but to lead the reader to an appreciation of some of the knottiest problems that
concern contemporary philosophers of science. In the first chapter, "Scientific
Explanation," Wesley C. Salmon discusses the elements involved in the special kind of
understanding of our world and what takes place within it that is provided by the various
sciences. In the second chapter, The Confirmation of Scientific Hypotheses," John
Earman and Wesley C. Salmon deal with questions concerning the relationship between
empirical evidence and scientific hypotheses, laws, and theories. In the course of the
discussion they consider the nature of inductive reasoning and the meanings of the
concept of probability. Chapter 3, by Clark Glymour, considers the major traditional
arguments against literal belief in the claims
4
Introduction
of science and a range of responses to those arguments. In the fourth chapter, J. E. McGuire discusses the nature of
scientific change and progress in relation to social context and historical development.
In the remaining seven chapters, each of which deals with the philosophy of a special area of science, the authors assume
that the reader is familiar with the issues addressed in the first four chapters, though some topics depend less heavily on
this than others. The chapters in Parts Two through Four can be read independently of one another, although they do
contain references to the materials covered in other chapters.
The philosophy of physical sciences is covered in Part Two (Chapters 5 and 6). In "The Philosophy of Space and Time,"
John D. Norton introduces questions central to recent work in philosophy of space and time and illustrates how
philosophical ideas about verification, conventions, realism, and theory reduction are applied in physical theories of
space and time. In "Determinism in the Physical Sciences," John Barman surveys the implications of classical physics,
the special and general theories of relativity, and quantum mechanics for the doctrine that the world evolves in a
deterministic manner.
Part Three takes up the philosophy of biology and medicine with separate chapters on these topics. In "Philosophy of
Biology," James G. Lennox discusses the development of the so-called neo-Darwinian theory of evolution. Lennox
shows how this union ofMendelian genetics and Darwin's theory of natural selection provides a powerful tool for
explaining evolutionary change and adaptation that operates differently from theories in the physical sciences. In
"Philosophy of Medicine," Kenneth F. Schaffner, who has been trained as a physician as well as an historian and
philosopher of science, discusses the questions of whether medicine is a science and whether medicine can be reduced to
biology. He examines the nature of medicine as an enterprise incorporating ethical principles and the implications of this
for medicine's reduction to biology. Part Four, on the behavioral sciences, begins with Peter Machamer's chapter on
"Philosophy of Psychology." This chapter briefly surveys the relationships between philosophy and psychology and lays
out some of the topics that are and have been important to an understanding of psychology. The bulk of the chapter,
however, describes and assesses the nature of psychological theories of perception. The author's intent is to provide a
case study of what philosophers who are interested in psychology might do. In Chapter 10, "Android Epistemology,"
dark Glymour discusses philosophical issues raised by the exciting new field of Artificial Intelligence. He illustrates the
influence of issues in philosophy of science on the design of artificial intelligence and expert systems programs. In the
final chapter, "Philosophy of Social Science," Merrilee H. Salmon addresses the issue of whether the so-called social
sciences really are entitled to the name, and discusses some of the special problems posed by disciplines that try to
explain human behavior by using the same methods thai have been so successful in the physical sciences.
Merrilee H. Salmon
Introduction
5