Lindley Darden’s "Reasoning in
Biological Discovery: Essays on Mechanisms, Interfield Relations and Anomaly
Resolution" is a collection of papers, some co-authored, that span three
decades and cover a range of topics.  Despite this diversity, the book also
presents a unified approach to philosophy of biological sciences that centers on
strategies for characterizing biological mechanisms.  The book is divided into
three sections: part I consists of four papers on biological mechanisms, part
II consists of seven papers on reasoning strategies in biological sciences,
with a particular focus on strategies for resolving anomalies.  The final
section is one paper, written for this volume, that summarizes the preceding
work, describes the development of Darden’s (and her colleagues) views on
mechanism in response to criticisms or to alternative accounts, and draws
explicit connections between Darden’s work on mechanisms and her work on
discovery in biological sciences. 

Philosophical research on mechanisms in biology
seems to be at an interesting stage in its development; the field is large enough
that there is a diversity of opinions and approaches, but small enough that
those working in this area can easily read and respond to each others’ work. 
The first paper in section I of this book: "Thinking About Mechanisms"
has generated a great deal of discussion.  The paper was co-written with Peter
Machamer and Carl Craver, and presents a sketch of the nature and
characteristics of biological mechanisms that is known (after its creators) as
the "MDC view."  This view gives a "dualist" characterization
of mechanisms, on which both the entities that make up a mechanism and the
activities that those entities engage in are fundamental to the mechanism and
to its characterization.  The rest of "Thinking About Mechanisms"
expands on and gives examples of this view of mechanisms, as do the other
papers in this section.  The examples are drawn from molecular biology, often
in the context of the development of its relationship with biochemistry or
molecular genetics and from Darden’s work with Carl Craver on neuroscience. 
The papers describe methods for studying the structure of a mechanism in
greater detail, focusing on the way in which experiments lead to the discovery
of the details of a mechanism.

The second section expands the discussion of
discovery in biological science to consider situations in which a specific
experimental approach is not sufficient to characterize a mechanism.  This may
occur when the techniques or concepts of a particular area of science are not
suited to, or provide too narrow a characterization of, the problem being
solved, or when an anomaly occurs that the current knowledge of the mechanism
cannot explain.  The first paper, co-written with Nancy Maull, introduces the
idea of "interfield theories," where a field is "an area of science
consisting of the following elements: a central problem, a domain consisting of
items taken to be facts related to that problem, general explanatory factors
and goals providing expectations as to how the problem is to be solved, and
sometimes but not always, concepts, laws and theories which are related to the
problem and which attempt to realize the explanatory goals" (p. 128). 
Because scientists in different fields may approach related problems from
different perspectives, or may discover as work progresses that they are
investigating the same or a related problem, many biological theories span more
than one field.  Darden and Maull outline a number of ways in which fields may
be related and, again, provide detailed examples of the development of interfield
theories.  The next few papers in this section give extended examples of the
way in which interfield theories have been developed in genetics and in the
synthetic theory of evolution.

The second theme taken up in this section is how
scientists do (or should) deal with anomalies that arise in the course of their
research.  In "Strategies for Anomaly Resolution," Darden draws on
work in artificial intelligence to describe the process of anomaly resolution
as a type of problem solving.  She points out that not all anomalies are a real
problem for a theory and then describes strategies for dealing with those that
do indicate a need to revise the theory.  In the last two papers in this
section, she returns to Mendelian and molecular genetics to illustrate the
nature of and the resolution of, anomalies. 

The third section of the book consists of one
paper, written specifically for this volume, that draws together Darden’s work
on mechanisms and her work on biological discovery.  She begins by expanding on
the MDC view and addressing criticisms of the view.  She then outlines a number
of strategies for developing and testing hypotheses about how a mechanism
works, and for revising hypotheses in the face of an anomaly.  Although this
paper repeats many of the concepts and examples discussed in the earlier
chapters of the book, it is valuable because it provides a summary and synthesis
of Darden’s work.  In particular, it links the discussion of the development of
the description of a mechanism (in part I of the book) with the discussion of
anomaly resolution (in part II).  On Darden’s view, "discovery [of
mechanisms] occurs piecemeal and incrementally, with iterative refinement via
construction, evaluation, and revision" (p. 301).  Because of this, the
need to resolve anomalies plays an important role in the elucidation of
mechanisms.

Missing from this third section, however, is an
explicit discussion of the relationship between "interfield theories"
and mechanisms.  This link seems to be a natural one given that part I describes
the hierarchical nature of biological mechanisms.  Since different fields often
investigate phenomenal that turn out to be caused by different "levels"
of mechanisms in the same hierarchy, some discussion of the way in which diverse
fields contribute to the discovery of the hierarchical structure of mechanisms
would have been interesting.

Throughout the book, Darden
emphasizes the importance of historically-informed examples in philosophy of
science; she does not claim to give a definitive account of scientific
discovery in biological science, but rather to provide a series of exemplars
that make explicit some of the strategies that have — and that have not —
been successful in the past.  Darden describes the history of science as providing
"compiled hindsight" that can inform the strategies chosen by
contemporary scientists.  She further suggests that, since philosophers of
science tend to state these strategies more explicitly than scientists
themselves, philosophical work may be useful to scientists and also in science
education (p. 272).

Overall, this book is useful both
as an introduction to the philosophical literature on mechanisms and as an
overview of the main themes in Darden’s work.  It is a good introduction not
only because Darden’s views have had such an influence on recent work on
mechanisms in philosophy of science, but also because she discusses the work of
other philosophers throughout the papers and in the final chapter. The
philosophical literature on mechanisms is growing and is also increasing its
influence beyond the molecular and physiological processes that are the focus
of Darden’s own work to, for example, philosophy of chemistry, of psychology
and of sociology.  This new scholarship will almost certainly show the
influence of the papers in this collection.

© 2006 Robyn Bluhm

Robyn Bluhm, Ph.D. (Postdoctoral
Fellow in Neuropsychiatry, The University of Western Ontario)

Categories: Philosophical