Thomas A. C. Reydon

The taxa that appear in biological classifications are commonly seen as representing information about the traits of their member organisms. This paper examines in what way taxa feature in the storage and retrieval of such information. I will argue that taxa do not actually store much information about the traits of their member organisms. Rather, I want to suggest, taxa should be understood as functioning to localize organisms in the genealogical network of life on Earth. Taxa store information about where organisms are localized in the network, which is important background information when it comes to establishing knowledge about organismal traits, but it is not itself information about these traits. The view of species and higher taxa that is proposed here follows from examining three problems that occur in contemporary biological systematics and are discussed here: the problem of generalization over taxa, the problem of phylogenetic inference, and the problematic nature of the Tree of Life.

The philosophy of biology is witnessing an increasing enthusiasm for what can be called “individuals thinking”. Individuals thinking is a perspective on the metaphysics of biological entities according to which conceiving of them as individuals rather than kinds enables us to expose ongoing metaphysical debates as focusing on the wrong question, and to achieve better accounts of the metaphysics of biological entities. In this paper, I examine two cases of individuals thinking, the claim that species are individuals and the claim that life on Earth is an individual. I argue that these claims fail to do the metaphysical work that one would want them to do. I highlight problems with the specific claims as well as with the general notion of ‘individual’, and argue that naturalistic metaphysicians of biology should think of the metaphysical status of theoretical entities, such as species and life, as fundamentally theory-dependent. This implies a metaphysical pluralism, that allows that in some theories species, life, and other such entities may feature as individuals, whereas in others they may feature as kinds.

Natural kinds are often contrasted with other kinds of scientific kinds, especially functional kinds, because of a presumed categorical difference in explanatory value: supposedly, natural kinds can ground explanations, while other kinds of kinds cannot. I argue against this view of natural kinds by examining a particular type of explanation—mechanistic explanation—and showing that functional kinds do the same work there as traditionally recognized natural kinds are supposed to do in “standard” scientific explanations. Breaking down this categorical distinction between traditional natural kinds and other kinds of kinds, I argue, delivers two goods: It provides us with a view of natural kindhood that does justice to the epistemic roles of kinds in scientific explanations. And it allows us to solve a problem that HPC theory, currently one of the more popular accounts of natural kindhood, confronts.

This paper compares two approaches that attempt to explain the origin of life, or biogenesis. The more established approach is one based on chemical principles, whereas a new, yet not widely known approach begins from a physical perspective. According to the first approach, life would have begun with—often organic—compounds. After having developed to a certain level of complexity and mutual dependence within a non-compartmentalised organic soup, they would have assembled into a functioning cell. In contrast, the second, physical type of approach has life developing within tiny compartments from the beginning. It emphasises the importance of redox reactions between inorganic elements and compounds found on two sides of a compartmental boundary. Without this boundary, “life” would not have begun, nor have been maintained; this boundary—and the complex cell membrane that evolved from it—forms the essence of life.

A major issue in philosophical debates on the species problem concerns the opposition between two seemingly incompatible views of the metaphysics of species: the view that species are individuals and the view that species are natural kinds. In two recent papers in this journal, Olivier Rieppel suggested that this opposition is much less deep than it seems at first sight. Rieppel used a recently developed philosophical account of natural kindhood, namely Richard Boyd’s “homeostatic property cluster” theory, to argue that every species taxon can be conceived of as an individual that constitutes the single member of its own specific natural kind. In this paper I criticize Rieppel’s approach and argue that it does not deliver what it is supposed to, namely an account of species as kinds about which generalized statements can be made.

The more one reads about the topic of natural kinds, the more one is reminded of that famous scene in The Hitchhiker’s Guide to the Galaxy in which Deep Thought—after a mere 7.5 million years of doing calculations—reveals that the answer to the Ultimate Question of Life, the Universe and Everything was 42. Faced with bewildered reactions from the eager audience, Deep Thought explains: “I think the problem, to be quite honest with you, is that you’ve never actually known what the question is” .In the case of the growing literature on natural kinds, it is easy to get a feeling that something similar is going on. While philosophers keep advancing novel accounts of natural kinds, at the same time there is considerable disagreement about what exactly the problem is that such accounts should solve. To some, natural kinds are real kinds in nature that exist in the world independently of human interests and practices. At the very least, they are human-made kinds that correspon ..

Fragt man heute Vertreter verschiedener Disziplinen nach der Bedeutung des Hannoveraner Universalgelehrten Gottfried Wilhelm Leibniz, so hort man jeweils immer wieder: Leibniz hat Bedeutendes fur unser Fach geleistet. Leibniz beeindruckt nicht nur durch die Exzellenz seiner Leistung, sondern auch durch die Breite seiner Betatigungsfelder. Der aus einer Ringvorlesung an der Leibniz Universitat Hannover hervorgegangene Band fuhrt nun an die Vielfalt der von Leibniz ausgehenden der Leistungen und Anregungen heran. Insbesondere behandeln die Beitrage die Bedeutung von Leibniz fur die Geschichtswissenschaft, die Theologie, die Philosophie, die Rechtswissenschaft und Juristerei, die Politikberatung, das Versicherungswesen, die Mathematik, die Ingenieurwissenschaften und die Sprachwissenschaft. Abgerundet wird der Band durch eine Einfuhrung von Werner Eisner und eine biographische Skizze aus der Feder von Eike Christian Hirsch.

Despite many years of discussion, the species problem has still not been adequately resolved. Why is this the case? Here I discuss two recent suggested answers to this question that place the blame on the species problem's empirical aspects or on its philosophical aspects. In contrast, I argue that neither of these two faces of the species problem constitute the principal cause of the species problem's persistence. Rather, they are merely symptoms of the real cause: the species problem has not yet gone away because of a failure to recognize that not one but a number of distinct concepts are at the heart of the problem. To illustrate this point, a recently proposed solution to the problem is examined: the suggestion to understand the concept of species as a family resemblance concept. BioEssays 26:300–305, 2004. © 2004 Wiley Periodicals, Inc.