It is commonly held that objects in the world form natural kinds. Rabbits form a natural kind and so do all pieces of gold. The traditional account of natural kinds asserts that the members of a kind share a common essence. The essence of gold, for example, is its unique atomic structure. That structure occurs in all and only pieces of gold, and it is a property that all pieces of gold must have.
Darwin oﬀered an intriguing answer to the species problem. He doubted the existence of the species category as a real category in nature, but he did not doubt the existence of those taxa called ‘‘species’’. And despite his scepticism of the species category, Darwin continued using the word ‘‘species’’. Many have said that Darwin did not understand the nature of species. Yet his answer to the species problem is both theoretically sound and practical. On the theoretical side, DarwinÕs answer is (...) conﬁrmed by contemporary biology, and it oﬀers a more satisfactory answer to the species problem than recent attempts to save the species category. On the practical side, DarwinÕs answer frees us from the search for the correct theoretical deﬁnition of ‘‘species’’. But at the same time it does not require that we banish the word ‘‘species’’ from biology as some recent sceptics of the species category advocate. Ó The Willi Hennig Society 2010. (shrink)
The importance of homology in biology is widely acknowledged. Wake (1994: 284) writes that “[h]omology is the central concept for all of biology.” Paterson (1987: 18) observes that “all useful comparisons in biology depend on the relation of homology.” Whenever we ask if two characters are the same character we are asking if they are homologous, regardless of whether those characters are genetic, morphological, anatomical, or behavioral. Yet like many central concepts in biology, our understanding of homology is plagued by (...) unresolved questions. For example, how should we define ‘homology’? There is no agreed upon definition in the literature. Or, how do we explain the fact that two homologous characters can be caused by non-homologous developmental factors (Hall 2007)? Or more fundamentally, what causes new homologues (Wagner 2001)? Then there are questions about the role of homologies in evolution. Homologues are quasi-independent, heritable units that selection acts on; they are units of evolvability (Laubichler 2000; Brigandt 2007). The idea of homologues as units of evolvability cries out for analysis. These are all pressing questions, but this paper will focus on just two of them. One is the possibility of a unified theoretical account of homology. The other is how homologues at one hierarchical level are caused by non-homologues at a lower level. As we shall see, recent work offers an emerging approach to homology that integrates phylogeny and development (Laubichler 2000). Such an approach provides the basis for a unified theoretical account of homology, and it sheds light on the hierarchical nature of homology. (shrink)
To cite this Article: Ereshefsky, Marc , 'Foundational Issues Concerning Taxa and Taxon Names', Systematic Biology, 56:2, 295 - 301 To link to this article: DOI: 10.1080/10635150701317401 URL: http://dx.doi.org/10.1080/10635150701317401..
This paper examines David Hull’s and Peter Godfrey-Smith’s accounts of biological individuality using the case of biofilms. Biofilms fail standard criteria for individuality, such as having reproductive bottlenecks and forming parent-offspring lineages. Nevertheless, biofilms are good candidates for individuals. The nature of biofilms shows that Godfrey-Smith’s account of individuality, with its reliance on reproduction, is too restrictive. Hull’s interactor notion of individuality better captures biofilms, and we argue that it offers a better account of biological individuality. However, Hull’s notion of (...) interactor needs more precision. We suggest some ways to make Hull’s notion of interactor and his account of individuality more precise. Generally, we maintain that biofilms are a good test case for theories of individuality, and a careful examination of biofilms furthers our understanding of biological individuality. (shrink)
This paper explores an important type of biological explanation called ‘homology thinking.’ Homology thinking explains the properties of a homologue by citing the history of a homologue. Homology thinking is significant in several ways. First, it offers more detailed explanations of biological phenomena than corresponding analogy explanations. Second, it provides an important explanation of character similarity and difference. Third, homology thinking offers a promising account of multiple realizability in biology.
Biologists and philosophers that debate the existence of the species category fall into two camps. Some believe that the species category does not exist and the term 'species' should be eliminated from biology. Others believe that with new biological insights or the application of philosophical ideas, we can be confident that the species category exists. This paper offers a different approach to the species problem. We should be skeptical of the species category, but not skeptical of the existence of those (...) taxa biologists call 'species.' And despite skepticism over the species category, there are pragmatic reasons for keeping the word 'species.' This approach to the species problem is not new. Darwin employed a similar strategy to the species problem 150 years ago. (shrink)
This paper examines the species problem in microbiology and its implications for the species problem more generally. Given the different meanings of ‘species’ in microbiology, the use of ‘species’ in biology is more multifarious and problematic than commonly recognized. So much so, that recent work in microbial systematics casts doubt on the existence of a prokaryote species category in nature. It also casts doubt on the existence of a general species category for all of life (one that includes both prokaryotes (...) and eukaryotes). Prokaryote biology also undermines recent attempts to save the species category, such as the suggestion that species are metapopulation lineages and the idea that ‘species’ is a family resemblance concept. (shrink)
The received view in the philosophy of biology is that biological taxa (species and higher taxa) do not have essences. Recently, some philosophers (Boyd, Devitt, Grifﬁths, LaPorte, Okasha, and Wilson) have suggested new forms of biological essentialism. They argue that according to these new forms of essentialism, biological taxa do have essences. This article critically evaluates the new biological essentialism. This article’s thesis is that the costs of adopting the new biological essentialism are many, yet the beneﬁts are none, so (...) there is no compelling reason to resurrect essentialism concerning biological taxa. (shrink)
In a series of articles, Rieppel (2005, Biol. Philos. 20:465–487; 2006a, Cladistics 22:186–197; 2006b, Systematist 26:5–9), Keller et al. (2003, Bot. Rev. 69:93–110), and Nixon and Carpenter (2000, Cladistics 16:298–318) criticize the philosophical foundations of the PhyloCode. They argue that species and higher taxa are not individuals, and they reject the view that taxon names are rigid designators. Furthermore, they charge supporters of the individuality thesis and rigid designator theory with assuming essentialism, committing logical inconsistencies, and offering proposals that render (...) taxonomy untestable. These charges are unsound. Such charges turn on confusions over rigid designator theory and the distinction between kinds and individuals. In addition, Rieppel’s, Keller et al.’s, and Nixon and Carpenter’s proposed alternatives are no better and have their own problems. The individuality thesis and rigid designator theory should not be quickly abandoned. [Individuals; kinds; PhyloCode; rigid designators; species; taxa; taxon names.]. (shrink)
Environmental philosophers spend considerable time drawing the divide between humans and the rest of nature. Some argue that humans and our actions are unnatural. Others allow that humans are natural, but maintain that humans are nevertheless distinct. The motivation for distinguishing humans from the rest of nature is the desire to determine what aspects of the environment should be preserved. The standard view is that we should preserve those aspects of the environment outside of humans and our inﬂuence. This paper (...) examines the standard view by asking two questions. First, are the suggested grounds for distinguishing humans from the rest of the environment viable? Second, is such a distinction even needed for determining what to preserve? The paper concludes that debates over whether humans are natural and whether humans are unique are unhelpful when deciding what to preserve. (shrink)
Homeostatic Property Cluster (HPC) theory suggests that species and other biological taxa consist of organisms that share certain similarities. HPC theory acknowledges the existence of Darwinian variation within biological taxa. The claim is that “homeostatic mechanisms” acting on the members of such taxa nonetheless ensure a significant cluster of similarities. The HPC theorist’s focus on individual similarities is inadequate to account for stable polymorphism within taxa, and fails properly to capture their historical nature. A better approach is to treat distributions (...) of traits in species populations as irreducible facts, explained in terms of selection pressures, genealogy, and other evolutionary factors. We call this view Population Structure Theory (PST). PST accommodates the view, implicit in biological systematics, that species are identified by reference to particular historical populations. (shrink)
Many writers claim that human kinds are significantly different from biological and natural kinds. Some suggest that humans kinds are unique because social structures are essential for the etiology of human kinds. Others argue that human cultural evolution is decidedly different from other forms of evolution. In this paper I suggest that the gulf between humans and our biological relatives is not as wide as some argue. There is a taxonomic difference between human and nonhuman organisms, but such factors as (...) social structure and cultural evolution do not distinguish us from many other organisms. (shrink)
The vast majority of biological taxonomists use the Linnaean system when constructing classifications. Taxa are assigned Linnaean ranks and taxon names are devised according to the Linnaean rules of nomenclature. Unfortunately, the Linnaean system has become theoretically outdated. Moreover, its continued use causes a number of practical problems. This paper begins by sketching the ontological and practical problems facing the Linnaean system. Those problems are sufficiently pressing that alternative systems of classification should be investigated. A number of proposals for an (...) alternative system are introduced and evaluated. The best aspects of those proposals are brought together to form a post-Linnaean system, and a comparison of the Linnaean and post-Linnaean systems is conducted. The final section of this paper considers not only the theoretical reasons for replacing the Linnaean system, but also the practical feasibility of adopting an alternative system. (shrink)
The question of whether biologists should continue to use the Linnaean hierarchy is a hotly debated issue. Invented before the introduction of evolutionary theory, Linnaeus's system of classifying organisms is based on outdated theoretical assumptions, and is thought to be unable to provide accurate biological classifications. Marc Ereshefsky argues that biologists should abandon the Linnaean system and adopt an alternative that is more in line with evolutionary theory. He traces the evolution of the Linnaean hierarchy from its introduction to the (...) present. He illustrates how the continued use of this system hampers our ability to classify the organic world, and then goes on to make specific recommendations for a post-Linnaean method of classification. Accessible to a wide range of readers by providing introductory chapters to the philosophy of classification and the taxonomy of biology, the book will interest both scholars and students of biology and the philosophy of science. (shrink)
Species pluralism gives us reason to doubt the existence of the species category. The problem is not that species concepts are chosen according to our interests or that pluralism and the desire for hierarchical classifications are incompatible. The problem is that the various taxa we call 'species' lack a common unifying feature.
The Linnaean system of classification is a threefold system of theoretical assumptions, sorting rules, and rules of nomenclature. Over time, that system has lost its theoretical assumptions as well as its sorting rules. Cladistic revisions have left it less and less Linnaean. And what remains of the system is flawed on pragmatic grounds. Taking all of this into account, it is time to consider alternative systems of classification.
Several authors have argued for taxonomic pluralism in biology -the position that there is a plurality of equally legitimate classifications of the organic world. Others have objected that such pluralism boils down to a position of anything goes. This paper offers a response to the anything goes objection by showing how one can be a discerning pluralist. In particular, methodological standards for choosing taxonomic projects are derived using Laudan's normative naturalism. This paper also sheds light on why taxonomic pluralism (...) occurs in biology as well as illustrates the usefulness of normative naturalism. (shrink)
Most biologists use the Linnaean system for constructing classifications of the organic world. The Linnaean system, however, has lost its theoretical basis due to the shift in biology from creationist and essentialist tenets to evolutionary theory. As a result, the Linnaean system is both cumbersome and ontologically vacuous. This paper illustrates the problems facing the Linnaean system, and ends with a brief introduction to an alternative approach to biological classification.
This paper takes up the cause of species pluralism. An argument for species pluralism is provided and standard monist objections to pluralism are answered. A new form of species pluralism is developed and shown to be an improvement over previous forms. This paper also offers a general foundation on which to base a pluralistic approach to biological classification.
A number of authors argue that while species are evolutionary units, individuals and real entities, higher taxa are not. I argue that drawing the divide between species and higher taxa along such lines has not been successful. Common conceptions of evolutionary units either include or exclude both types of taxa. Most species, like all higher taxa, are not individuals, but historical entities. Furthermore, higher taxa are neither more nor less real than species. None of this implies that there is no (...) distinction between species and higher taxa; the point is that such a distinction is more subtle than many authors have claimed. (shrink)
Paul Thompson, John Beatty, and Elisabeth Lloyd argue that attempts to resolve certain conceptual issues within evolutionary biology have failed because of a general adherence to the received view of scientific theories. They maintain that such issues can be clarified and resolved when one adopts a semantic approach to theories. In this paper, I argue that such conceptual issues are just as problematic on a semantic approach. Such issues arise from the complexity involved in providing formal accounts of theoretical laws (...) and scientific explanations. That complexity is due to empirical and pragmatic considerations, not one's adherence to a particular formal approach to theories. This analysis raises a broader question. How can any formal account properly represent the complex nature of empirical phenomena? (shrink)
In her "Species Are Individuals" (1985), Mary Williams offers informal arguments and a sketched proof which allegedly show that species are individuals with respect to evolutionary theory. In this paper, I suggest that her informal arguments are insufficient for showing that clans are not sets and that species are individuals. I also argue that her sketched proof depends on three questionable assumptions.
A number of authors have argued that the thesis that species are individuals has important implications for macroevolutionary theory. More specifically, some authors claim that the thesis lends support to the Theory of Punctuated Equilibrium and indicates the existence of species selection. In this paper, I argue that the alleged individuality of species is neither necessary nor sufficient for the truth of that theory or for the existence of species selection. I also argue, contrary to the claims of some, that (...) the individuality of a group is not a necessary requirement for a group to be a unit of selection. (shrink)