## 1. Pre-history of Philosophy of Biology



As is the case for most apparent novelties, closer inspection reveals
a pre-history for the philosophy of biology (Grene & Depew 2004).
In the 1950s the biologist J. H. Woodger and the philosopher Morton
Beckner both published major works on the philosophy of biology
(Woodger 1952; Beckner 1959), but these did not give rise to a
subsequent philosophical literature (though see Ruse 1988). Some
philosophers of science also made claims about biology based on
general epistemological and metaphysical considerations. One of the
most famous examples is J. J. C. Smart's claim that the biology
is not an autonomous science, but a technological application of more
basic sciences, like "radio-engineering" (Smart 1959,
366). Like engineering, biology cannot make any addition to the laws
of nature. It can only reveal how the laws of physics and chemistry
play out in the context of particular sorts of initial and boundary
conditions (for more recent discussions of biological laws, see Beatty
1995; Brandon 1997; Mitchell 1997; Sober 1997; Waters 1998). Even in
1969 the zoologist Ernst Mayr could complain that books with
'philosophy of science' in the title were all misleading
and should be re-titled 'philosophy of physics' (Mayr
1969). It is worth noting however that philosophers of science such as
Carl G. Hempel (1965) and Ernest Nagel (1961) offered accounts of
functional explanation as found in the biological sciences. The
encouragement of prominent biologists such as Mayr and F. J. Ayala
(Ayala 1976; Mayr 1982) was one factor in the emergence of the new
field. Another factor was that several philosophers of science
including Robert Brandon, Phillip Kitcher, Elisabeth Lloyd, Sahotra
Sarkar, Elliott Sober, and William C. Wimsatt did research at Harvard
University with the likes of Stephen Jay Gould, Richard Lewontin, and
Richard Levins (Callebaut 1993). The first sign of philosophy of
biology becoming a mainstream part of philosophy of science was the
publication of David Hull's *Philosophy of Biological
Science* in the prominent Prentice-Hall Foundations of Philosophy
series (Hull 1974). From then on the field developed rapidly. Robert
Brandon could say of the late 1970's that "I knew five
philosophers of biology: Marjorie Grene, David Hull, Michael Ruse,
Mary Williams and William Wimsatt." (Brandon 1996,
xii-xiii) By 1986, however, there were more than enough to fill
the pages of Michael Ruse's new journal *Biology and
Philosophy*. This trend has only increased with the introduction
of additional journals such as *Biological Theory*,
*Philosophy and Practice of Biology*, *History and
Philosophy of the Life Sciences*, and *Studies in History and
Philosophy of Biological and Biomedical Sciences*. 


## 2. Three Types of Philosophy of Biology



Three different kinds of philosophical inquiry fall under the general
heading of philosophy of biology. First, general theses in the
philosophy of science are addressed in the context of biology. Second,
conceptual (or theoretical) problems within biology itself are
subjected to philosophical analysis. Third, appeals to biology are
made in discussions of traditional philosophical questions. The first
major debate in the philosophy of biology exemplified the first of
these, the use of genetics to explore reductionism and
anti-reductionism in the philosophy of science. Kenneth F. Schaffner
applied the logical empiricist model of theory reduction to the
relationship between classical, Mendelian genetics and molecular
genetics (Schaffner 1967a; Schaffner 1967b; Schaffner 1969). David
Hull argued that the lesson of this attempt was that Mendelian
genetics is irreducible to molecular genetics (Hull 1974; Hull 1975).
This debate reinforced the near-consensus in the 1970s and 1980s that
the special sciences are autonomous from the more fundamental sciences
(Fodor 1974; Kitcher 1984). However, the apparent absurdity of the
claim that the molecular revolution in biology was not a successful
instance of scientific reduction also led the formulation of
increasingly more adequate models of theory reduction (Wimsatt 1976;
Wimsatt 1980; Schaffner 1993; Waters 1994; Rosenberg 1997; Sarkar
1998). 



In another important early debate philosophers set out to solve a
conceptual problem within biology itself. The concept of reproductive
fitness is at the heart of evolutionary theory, but its status has
always been problematic. It has proved surprisingly hard for
biologists to avoid the criticism that, "[i]f we try to make
laws of evolution in the strict sense we seem to reduce to
tautologies. Thus suppose we say that even in Andromeda 'the
fittest will survive' we say nothing, for 'fittest'
has to be defined in terms of 'survival'" (Smart
1959, 366). This came to be know as the "tautology
problem". Alexander Rosenberg and Mary B. Williams argued that
fitness is an irreducible primitive which derives its meaning from its
place in an axiomatic formulation of evolutionary theory (Rosenberg
1983; Sober 1984a; Williams and Rosenberg 1985). If correct, this
would solve the tautology problem since axioms are often thought of as
tautologous. In the 1970's the new generation of philosophers of
biology offered a different solution to the tautology problem in two
steps. First, they began by arguing that fitness is a supervenient
property of organisms: the fitness of each particular organism is
necessarily dependent on some specific set of physical characteristics
of the organism and its particular environment, but two organisms that
have the same fitness may do so in virtue very different sets of
physical characteristics (Rosenberg 1978). Second, they argued that
this supervenient property is a *propensity* - which is a
probabilistic disposition represented by a probability distribution
over possible numbers of offspring (Mills and Beatty 1979). Although
fitness is defined in terms of reproductive success, it is not a
tautology that the fittest organisms have the most offspring, any more
than it is a tautology that dice produce even numbers more often than
they produce sixes. The propensities of fit organisms to survive and
of dice to fall equally often on each side both allow us to make
fallible predictions about what will happen, predictions that become
more reliable as the size of the sample increases. It remains unclear,
however, whether it is possible to specify a probability distribution
or set of distributions that can play all the roles actually played by
fitness in population biology (Beatty & Finsen 1989, Sober 2001;
Pence & Ramsey 2013).



The phrase 'conceptual problems' should be understood very
broadly. The conceptual work done by philosophers of biology in many
cases merges smoothly into theoretical biology. It also sometimes
leads philosophers to examine and criticize the chains of argument
constructed by biologists, and thus to enter directly into ongoing
biological debates. In the same way, the first kind of philosophy of
biology we have described - the use of biological examples to work
through general issues in the philosophy of science - sometimes
feeds back into biology itself through specific recommendations for
improving biological methodology. It is a striking feature of the
philosophy of biology literature that philosophers often publish in
biology journals and that biologists often contribute to philosophy of
biology journals. The philosophy of biology also has a potentially
important role as a mediator between biology and society. Popular
representations of biology derive broad lessons from large swathes of
experimental findings and theoretical work. Philosophers of science
have an obvious role in evaluating these interpretations of the
significance of specific biological findings (Stotz and Griffiths
2008). As two important examples, philosophers of biology have
provided a great deal of clarity regarding creationism/intelligent
design (Kitcher 1982; Ruse 1982; Pennock 2000; Sarkar 2007) and
sociobiology/evolutionary psychology (Kitcher 1985; Buller 2006;
Richardson 2010; Barker 2015). 



A third form of philosophy of biology occurs when philosophers appeal
to biology to support positions on traditional philosophical topics,
such as ethics or epistemology. The extensive literature on biological
teleology is a case in point. After a brief flurry of interest in the
wake of the "modern synthesis", during which the term
'teleonomy' was introduced to denote the specifically
evolutionary interpretation of teleological language (Pittendrigh
1958), the ideas of function and goal directedness came to be regarded
as relatively unproblematic by evolutionary biologists. In the 1970s,
however, philosophers started to look to biology to provide a solid,
scientific basis for normative concepts, such as illness, disorder, or
malfunction (Wimsatt 1972; Wright 1973; Boorse 1976). Eventually, the
philosophical debate produced an analysis of teleological language
fundamentally similar to the view associated with modern synthesis
(Millikan 1984; Neander 1991; Godfrey-Smith 1994). According to the
"selected effects" theory of function, the functions of a
trait are those activities in virtue of which the trait was selected.
The idea of *proper function* has become part of the conceptual
toolkit of philosophy in general and of the philosophy of language and
the philosophy of mind in particular (Dretske 1991, 1997; Millikan
1995, 2004, 2005; Papineau 1987, 1993; Neander 2017; Garson 2019).


## 3. Philosophy of Evolutionary Biology



Philosophy of biology can also be subdivided by the particular areas
of biology with which it is concerned. Until recently, evolutionary
biology has attracted the lion's share of philosophical attention.
This work has sometimes been designed to support a general thesis in
the philosophy of science, such as the "semantic view" or
model-based view of theories (Beatty 1980; Lloyd 1988; Thompson 1988).
But most of this work is concerned with conceptual problems that arise
inside the theory itself, and the work often resembles theoretical
biology as much as pure philosophy of science. For example, Elliott
Sober's classic study *The Nature of Selection: Evolutionary Theory
in Philosophical Focus* (Sober 1984b) marks the point at which
many philosophers became aware of the philosophy of biology. Sober
analyzed the structure of population genetics via an analogy with
Newtonian mechanics and the composition of forces, treating the actual
change in gene frequencies over time as the result of several
different "forces", such as selection, random genetic
drift, mutation, and migration. Several philosophers of biology have
challenged this interpretation of evolutionary theory in favor of a
"statistical" approach (Sterelny & Kitcher 1988;
Matthen and Ariew 2002; Walsh, Lewens, and Ariew 2002), and this
debate continues. Another instance of a conceptual problem in
evolutionary theory concerns the nature of random genetic drift. How
are selection and drift distinct (Beatty 1987)? We typically think of
drift occurring when there is random fluctuation of gene frequencies,
but selection in a changing environment can produce the very same
pattern. Thus, some philosophers of biology have argued we must
distinguish selection and drift as processes rather than just as
patterns. One way to do this is through a distinction between
indiscriminate and discriminate sampling processes (Millstein 2002;
Brandon 2005; Millstein 2005). The question becomes whether the trait
of interest is causally irrelevant or relevant to changes in gene
frequencies. These examples of careful, methodological analysis of
population genetics, the mathematical core of traditional evolutionary
theory, continue to give rise to interesting results (Pigliucci and
Kaplan 2006; Plutynski 2006; Okasha 2007; Sarkar 2011).



The intense philosophical interest in evolutionary theory in the
1980's can partly be explained by two controversies
(Segerstrale 2000). First, there was a controversy over
"sociobiology" that was provoked by the publications of
E.O. Wilson's eponymous textbook (Wilson 1975) and his Pulitzer
prize winning popular book (Wilson 1978). One extremely important
critique of this application of evolutionary biology to human social
behavior came from Stephen Jay Gould and Richard Lewontin (Gould and
Lewontin 1979). The debates over adaptationism turned out to involve a
diffuse set of worries about whether evolution produces adaptations,
the role of optimality models, and the methodology of evolutionary
theory (Amundson 1994; Orzack and Sober 1994; Brandon and Rausher
1996; Godfrey-Smith 2001; Millstein 2007; Forber 2009; Potochnik 2009;
Lloyd 2015). Philosophical work has helped to distinguish these
strands in the debate and reduce the confusion seen in the heated and
polemical biological literature for and against adaptationism (Orzack
and Sober 2001). Second, there was the appearance of George
Williams' *Adaptation and Natural Selection* (Williams
1966) and Richard Dawkins' *The Selfish Gene* (Dawkins
1976). They claim that the unit of selection is the individual
Mendelian allele rather than the organism, group of organisms, or
species. This created an explosion of early philosophical work on the
"units of selection" question (Brandon and Burian 1984).
The early debates concerned whether there was a determinate unit of
selection and what criteria should be used for determining what it is
in a given case (Hull 1980; Wimsatt 1980a, 1980b; Brandon 1982; Sober
& Lewontin 1984; Lloyd 1988; Sterelny & Kitcher 1988). As
multi-level selection models and the Price equation appeared, close
attention turned to how those models should be interpreted
(Godfrey-Smith & Lewontin 1993; Godfrey-Smith & Kerr 2002;
Lloyd 2005; Waters 2005; Okasha 2006; Birch 2017). For example, for
any group selection model, is there an empirically equivalent
individual selection model (similarly for genotypic and genic models)?
If so, do they represent the very same causal structure? Is kin
selection a form of group selection? Arguably, philosophers made a
significant contribution to the rehabilitation of some forms of
"group selection" within evolutionary biology in the
1990s, following two decades of neglect or contempt (Sober and Wilson
1998).


## 4. Philosophy of Systematic Biology



Philosophical discussion of systematics was a response to a
"scientific revolution" in that discipline in the 1960s
and 1970s. This revolution saw the discipline transformed from
phenetics and evolutionary taxonomy alongside the application of
quantitative methods. The successor was the "cladistic"
approach due to Willi Hennig (1966), which argues that the sole aim of
systematics should be to represent "natural" groups of
organisms. Cladists took natural groups to be monophyletic groups
(where a monophyletic group includes an ancestor species and all of
its descendant species). Thus, a cladistic approach only represents
phylogeny, which is the pattern of common descent. Philosopher David L.
Hull was an active participant in scientific debates throughout these
two revolutions; in fact, he was president of the Society of
Systematic Zoology in 1984-1985 and of the Philosophy of Science
Association in 1985-1986 (Hull 1965; Hull 1970; Hull 1988; Sober
1988). Additionally, a great deal of conceptual work appeared on the
nature of phylogenetic inference. Phylogenies are commonly represented
with phylogenetic trees. Discovering phylogenies presents the familiar
problem of underdetermination of theory by evidence. For example, if
we have four taxa, there are fifteen possible rooted trees. However,
only one of those trees corresponds to the actual historical lineage.
Additionally, the phylogeny of given taxa cannot be directly observed,
and so must be inferred. Thus, the problem of phylogenetic inference
is how to justify such historical hypotheses. The original
phylogenetic method of choice was parsimony, which says to choose the
tree which proposes the fewest evolutionary events. Some phylogenetic
systematists argued for this approach using Sir Karl Popper's
falsificationism (Wiley 1975, Farris 1983). In the 1970's,
Joseph Felsenstein demonstrated that lineages with a certain topology
were subject to a systematic error in parsimony analysis (Felsenstein
1978, 2004). This is the problem of "long-branch
attraction" in which taxa at the end of long branches are
mistakenly grouped together by parsimony analysis, instead of with
taxa with which they share a more recent common ancestor (Haber 2008).
Felsenstein proposed using statistical techniques (in particular
maximum likelihood methods) to avoid this problem. Debates between the
camps continue (Sober 2004). 



The biologist Michael Ghiselin piqued the interest of philosophers
when he suggested that systematics was fundamentally mistaken about
the ontological status of biological species (Ghiselin 1974). Species
were not natural kinds in the way that chemical elements are. Instead,
they are historical particulars like nations or galaxies. They have a
beginning through speciation, they have parts that are integrated over
time by biological relations, and they cease to exist by going extinct
(Mishler & Brandon 1987). Additionally, individual organisms are
not instances of species, as a wedding ring is an instance of gold.
Instead, they are parts of species, as one is a part of a family. As
Smart had earlier noticed, this has the implication that there can be
no "laws of nature" about biological species per se, at
least in the traditional sense of 'laws of nature' (Smart
1959). David Hull further developed and argued for the "species
as individuals" thesis. He explored its implications for a
variety of topics including species names, laws of nature, and human
nature (Hull 1976, 1978, 1986). 



However, the view that species are individuals leaves other important
questions about species unsolved and raises new problems of its own
(Kitcher 1984, 1989). For example, suppose you are a population
biologist and you need to census the individuals in a population of
species. How do you decide what entities to count? Philosophers and
biologists have provided a variety of criteria for answering questions
like this including reproduction, life-cycles, genetics, sex,
developmental bottlenecks, germ-soma separation, policing mechanisms,
spatial boundaries or contiguity, immune response, fitness
maximization, cooperation and/or conflict, codispersal, adaptations,
metabolic autonomy, and functional integration (Clarke 2013). So, the
question of what a biological individual is indeed a pressing one
(Wilson 2005; Okasha 2006; Clarke 2011; Pradeu 2012; Bouchard and
Huneman 2013; Clarke 2013; Godfrey-Smith 2013; Wilson and Barker
2013).



Biologists have been, and are still, deeply divided over the species
category (Ereshefsky 1992b; Wheeler and Meier 2000; Coyne and Orr
2004; Wilkins 2009). Consider Ernst Mayr's famous biological
species concept (BSC). He writes, "Species are groups of
interbreeding natural populations that are reproductively isolated
from other such groups" (Mayr 1963, 89). There are lots of
concerns regarding the BSC (Ehrlich and Raven 1969; Sokal and Crovello
1970; Van Valen 1976; Wiley 1978). Asexual organisms do not
interbreed. Thus, on the BSC, there are no species of asexual
organisms. Many species exhibit some introgression, and thus cannot be
distinct species. Last, the BSC is extremely difficult to apply to
species in the fossil record since sex organs do not normally
fossilize, and reproductive behavior is difficult to corroborate. In
light of the problems with the BSC (and for other reasons), biologists
have put forward other species concepts. Species pluralism is the
claim that there is no single correct species concept that classifies
organisms exactly the same (Ereshefsky 1992a); rather, there are
several correct species concepts. That is, for some organisms,
different species concepts will correctly place them in distinct
species. Species monism is the claim that there is a single correct
species concept. Some allege species pluralism is temporary because we
will eventually find the single best concept (Hull 1999). The debate
between pluralists and monists rages on (Wilson 1999). 



Biological species are often given as one of the classic examples of a
"natural kind". The philosophy of systematics has had a
major influence on recent work on classification and natural kinds
(Dupre 1993, 2002; Wilson et. al. 1997; Boyd 1999; Griffiths
1999; Wilson 1999; Okasha 2001; Walsh 2006). For example, can there be
a notion of natural kind or essentialism consistent with the
"population thinking" found in biology (Mayr 1975, Sober
1980; Ariew 2008)? 


## 5. Philosophy of Molecular Biology



We mentioned above that the reduction of Mendelian genetics to
molecular genetics was one of the first topics to be discussed in the
philosophy of biology. The initial debate between Schaffner and Hull
was followed by the so-called "anti-reductionist
consensus" (Kitcher 1984). The reductionist position was revived
in a series of important papers by Kenneth Waters (1990, 1994) and
debate over the cognitive relationship between the two disciplines
continues today. However, the question is not now framed as a simple
choice between reduction and irreducibility (Griffiths 1999; Kitcher
1999; Sober 1999). Rather, a variety of concepts have been introduced
and discussed including multiple realizability, realization, and
mechanism (Wilson 2005, Craver 2007; Polger & Shapiro 2016). These
have been important in thinking about genetics but also neuroscience and
cell biology more generally. For example, Lindley Darden, Schaffner
and others have argued that explanations in molecular biology are not
neatly confined to one ontological level, and hence that ideas of
'reduction' derived from classical examples like the
reduction of the phenomenological gas laws to molecular kinematics in
nineteenth century physics are simply inapplicable (Darden and Maull
1977; Schaffner 1993). Moreover, molecular biology does not have the
kind of grand theory based around a set of laws or a set of
mathematical models that is familiar from the physical sciences.
Instead, highly specific mechanisms that have been uncovered in detail
in one model organism seem to act as "exemplars" allowing
the investigation of similar, although not necessarily identical,
mechanisms in other organisms that employ the same, or related,
molecular interactants. Darden and others have argued that these
"mechanisms" - specific collections of entities and
their distinctive activities - are the fundamental unit of
scientific discovery and scientific explanation, not only in molecular
biology, but in a wide range of special sciences (Machamer, Darden
*et al.* 2000; Craver & Darden 2013; see also Bechtel and
Richardson 1993). There is an interesting question about whether the
notion of mechanism aptly applies in other areas of biology (Skipper
& Millstein 2005; Havstad 2011). 



Another important topic in the philosophy of molecular biology has
been the concept of the gene (Beurton, Falk and Rheinberger 2000;
Waters 2000, 2004; Griffiths and Stotz 2007). Philosophers have also
written extensively on the concept of genetic information, the general
tenor of the literature being that it is difficult to reconstruct this
idea precisely in a way that does justice to the apparent weight
placed on it by molecular biologists (Sarkar 1996; Maynard Smith 2000;
Godfrey-Smith 2001; Griffiths 2001; Jablonka 2002; Rosenberg 2006).
For example, does DNA actually carry *semantic* information (Shea
2007)? If it does not, is this a useful fiction, or is it hindering
molecular biology (Levy 2001)? 


## 6. Philosophy of Developmental Biology



The debates over adaptationism in the 1980's made philosophers
familiar with the complex interactions between explanations of traits
in evolutionary biology and explanations of the same traits in
developmental biology. Developmental biology throws light on the kinds
of variation that are likely to be available for selection, posing the
question of how far the results of evolution can be understood in
terms of the options that were available ("developmental
constraints") rather than the natural selection of those options
(Maynard Smith, Burian *et al.* 1985). The debate over
developmental constraints looked at developmental biology solely from
the perspective of whether it could provide answers to evolutionary
questions. However, as Ron Amundson pointed out, developmental
biologists are addressing questions of their own, and, he argued, a
different concept of constraint is needed to address those questions
(Amundson 1994). The emergence in the 1990's of a new field
promising to unite both kinds of explanation, evolutionary
developmental biology, has given rise to a substantial philosophical
literature aimed at characterizing this field from a methodological
viewpoint (Gray 1992; Griffiths and Gray 1994; Oyama 2000a, 2000b;
Oyama, Griffiths, and Gray 2001; Maienschein and Laubichler 2004;
Robert 2004; Amundson 2005; Brandon and Sansom 2007). For example,
developmental systems theorists (Gray 1992; Griffiths and Gray 1994;
Oyama 2000a, 2000b; Oyama, Griffiths, and Gray 2001) argue for
"parity" between genes and non-genetic factors. First,
organisms inherit a "developmental matrix" and not just
genes (e.g. "epigenetic inheritance"). Second, the role of
genes is in the development of traits is not causally unique -
insofar as genes "carry information" or are
"copied" the same can be said of other factors. That is,
genes and developmental factors causally covary with phenotypic
traits. However, defenders of "extended replicators" argue
that genes uniquely carry information in a teleosemantic sense
(Sterelny et. al. 1996). Another source of philosophical controversy
in developmental biology concerns whether any traits are innate and
what innateness might be (Ariew 1999; Griffiths 2002; Mameli and
Bateson 2006). Philosophers have contributed to clarifying the
difference concepts at issue. 


## 7. Philosophy of Ecology and Conservation Biology



Until recently this was an extremely underdeveloped field in the
philosophy of biology. This is surprising, because there is obvious
potential for all three of the approaches to philosophy of biology
discussed above. There is also a substantial body of philosophical
work in environmental ethics, and answering the questions that arise
there would require a critical examination of ecology and conservation
biology (Brennan 2014). Over the last twenty years, this field has
developed rapidly (Colyvan et. al. 2009).



Philosophers have started to remedy the neglect of ecology and a
number of major books have appeared (Cooper 2003, Ginzburg and Colyvan
2004, Sarkar 2005, MacLaurin and Sterelny 2008). The discussions have
focused on several topics including the complicated and sometimes
troubled relationship between mathematical models and empirical data
in ecology (Shrader-Frechette & McCoy 1993; Ginzburg and Colyvan
2004; Odenbaugh 2005; Weisberg 2012), whether there are distinctive
ecological laws (Cooper 2003; Mikkelson 2003; Lange 2005; Eliot 2011b,
Linquist et. al. 2016), the nature and reality of ecological
communities and ecosystems (Sterelny 2006; Odenbaugh 2007; Eliot
2011), the "robustness" of ecological principles
(Odenbaugh 2003; Weisberg & Reisman 2008; Justus 2012), the idea
of ecological stability and the "balance of nature"
(Odenbaugh 2001; Cooper 2003; Mikkelson 2001; Justus 2008), the
definition of biodiversity (Sarkar 2005; MacLaurin and Sterelny 2008;
Santana 2014), and the relationship between ecology and conservation
biology (Linquist 2008). Recently, there has been interesting work
done on functions in ecology as well (Jax, 2005; Odenbaugh 2010;
Nunes-Neto et. al. 2014; Dussault & Bouchard 2017). Most
ecologists and evolutionary biologists do not think communities or
ecosystems are units of selection, and thus the selected-effects
account of functions does not readily apply. So, philosophers of
ecology have been exploring alternatives. 


## 8. Methodology in Philosophy of Biology and Future Directions



Most work in the philosophy of biology is self-consciously
naturalistic, recognizing no profound discontinuity in either method
or content between philosophy and science. Ideally, philosophy of
biology differs from biology itself not in its knowledge base, but
only in the questions it asks. The philosopher aims to engage with the
content of biology at a professional level, although typically with
greater knowledge of its history than biologists themselves, and fewer
hands-on skills. It is common for philosophers of biology to have
academic credentials in the fields that are the focus of their
research, and to be closely involved with scientific collaborators.
Philosophy of biology's naturalism and the continuity of its concerns
with science itself is shared with much other recent work in the
philosophy of science, perhaps most notably in the philosophy of
neuroscience (Bechtel, Mandik *et al.* 2001).



Even the distinction between the *questions* of biology and
those of philosophy of biology is not absolutely clear. As noted
above, philosophers of biology address three types of questions:
general questions about the nature of science, conceptual problems
within biology, and traditional philosophical questions that seem open
to illumination from the biosciences. When addressing the second sort
of question, there is no clear distinction between philosophy of
biology and theoretical biology. But while this can lead to the
accusation that philosophers of biology have abandoned their calling
for 'science reporting' it can equally well be said that a
book like *The Selfish Gene* (Dawkins 1976) is primarily a
contribution to philosophical discussion of biology. Certainly, the
professional skills of the philosopher are as relevant to these
internal conceptual puzzles as they are to the other two types of
question. All three types of question can be related to the specific
findings of the biological sciences only by complex chains of
argument.



There is a great deal of new work being in done in the philosophy of
biology. As examples, there is a rich philosophical literature
emerging around cancer (Plutynski 2018), cultural evolution (Sterelny
2012; Lewens 2015; O'Connor 2019), human nature (Machery 2008;
Ramsey 2013; Kronfeldner 2018), microbiology (O'Malley 2014),
and paleobiology (Turner 2011; Currie 2018). Philosophy of biology
still remains one of the most dynamic and interesting areas of the
philosophy of science and philosophy more generally.