Thomas A. C. Reydon

Recently, Barbara Renzi argued that Kuhn's account of scientific change is undermined by mismatches in the analogy that Kuhn supposedly draws between scientific change and biological evolution. We argue that Renzi's criticism is inadequate to Kuhn's account of scientific change, as Kuhn does not draw any precise analogy between the mechanisms of scientific change and biological evolution nor aims to argue that the mechanisms of scientific change and biological evolution are similar in any important respects. Therefore, pointing to mismatches between the central concepts that feature in the descriptions of the two phenomena simply misses the point of Kuhn's analogy. *Received January 2010; revised January 2010. †To contact the authors, please write to: Thomas A. C. Reydon, Leibniz Universität Hannover, Im Moore 21, D‐30167 Hannover, Germany; e‐mail: [email protected]‐hannover.de.

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.

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.

Present-day thought on the notion of species is troubled by a mistaken understanding of the nature of the issue: while the species problem is commonly understood as concerning the epistemology and ontology of one single scientific concept, I argue that in fact there are multiple distinct concepts at stake. An approach to the species problem is presented that interprets the term ‘species’ as the placeholder for four distinct scientific concepts, each having its own role in biological theory, and an explanation is given of the concepts involved. To illustrate how these concepts are commonly conflated, two widely accepted ideas on species are criticized: species individualism and species pluralism. I argue that by failing to distinguish between the four concepts and their particular roles in contemporary biological theory, these ideas stand in the way of a final resolution of the species problem

There is an interesting parallel between two debates in different domains of contemporary analytic philosophy. One is the endurantism– perdurantism, or three-dimensionalism vs. four-dimensionalism, debate in analytic metaphysics. The other is the debate on the species problem in philosophy of biology. In this paper I attempt to cross-fertilize these debates with the aim of exploiting some of the potential that the two debates have to advance each other. I address two issues. First, I explore what the case of species implies regarding the feasibility of particular positions in the endurantism– perdurantism debate. I argue that the case of species casts doubt on the recent claim that three-dimensionalism and four-dimensionalism are equivalent descriptions of the same underlying reality. Second, and conversely, I examine whether the metaphysical worry about three-dimensionalism and four-dimensionalism can help us to better understand the nature of biological species. I show that analyzing the thesis that species are individuals against the background of the endurantism– perdurantism debate allows us to explicate two different ways in which this thesis can be interpreted

Species in biology are traditionally perceived as kinds of organisms about which explanatory and predictive generalizations can be made, and biologists commonly use species in this manner. This perception of species is, however, in stark contrast with the currently accepted view that species are not kinds or classes at all, but individuals. In this paper I investigate the conditions under which the two views of species might be held simultaneously. Specifically, I ask whether upon acceptance of an ontology of species as diachronic segments of the tree of life species can perform the epistemic role of kinds of organisms to which explanatory and predictive generalizations apply. I show that, for species-level segments of the tree of life, several requirements have to be met before the performance of this epistemic role is possible, and I argue that these requirements can be met by defining species according to the Composite Species Concept proposed by Kornet and McAllister in the 1990s

Organizational ecology is commonly seen as a Darwinian research program that seeks to explain the diversity of organizational structures, properties and behaviors as the product of selection in past social environments in a similar manner as evolutionary biology seeks to explain the forms, properties and behaviors of organisms as consequences of selection in past natural environments. We argue that this explanatory strategy does not succeed because organizational ecology theory lacks an evolutionary mechanism that could be identified as the principal cause of organizational diversity. The “evolution” of organizational populations by means of selection, which organizational ecologists put forward as the mechanism responsible for the extant diversity of organizational forms, is not evolution in any proper sense, because organizational populations do not have what it takes to participate in evolutionary processes. This implies that organizational ecology is not a Darwinian research program and that it cannot explain organizational diversity

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.

Natural kinds have been a constant topic in philosophy throughout its history, but many issues pertaining to natural kinds still remain unresolved. This paper considers one of these issues: the epistemic role of natural kinds in scientific investigation. I begin by clarifying what is at stake for an individual scientific field when asking whether or not the field studies a natural kind. I use an example from life science, concerning how biologists explain the similar body shapes of fish and cetaceans, to show that natural kinds play a central epistemic role in scientific explanations that cannot be delegated to other explanatory factors. A task for philosophy, then, is to come up with a theory of natural kinds that adequately accounts for the epistemic role of natural kinds in science. After having sketched the spectrum of available philosophical theories of natural kinds, I argue that none of the available theories adequately performs this task and that therefore the search is still open for a theory that does.