I spell out and update the individuality thesis, that species are individuals, and not classes, sets, or kinds. I offer three complementary presentations of this thesis. First, as a way of resolving an inconsistent triad about natural kinds; second, as a phylogenetic systematics theoretical perspective; and, finally, as a novel recursive account of an evolved character. These approaches do different sorts of work, serving different interests. Presenting them together produces a taxonomy of the debates over the thesis, and isolates ways (...) it has been productive. This goes to the larger point of this paper: a defense of the individuality thesis in terms of its utility, and an update of it in light of recent theoretical developments and empirical work in biology. (shrink)

When developing phylogenetic systematics, the entomologist Willi Hennig adopted elements from Nicolai Hartmann’s ontology. In this historical essay I take on the task of documenting this adoption. I argue that in order to build a metaphysical foundation for phylogenetic systematics, Hennig adopted from Hartmann four main metaphysical theses. These are (1) that what is real is what is temporal; (2) that the criterion of individuality is to have duration; (3) that species are supra-individuals; and (4) that there are levels of (...) reality, each of which may be subject to different kinds of law. Reliance on Hartmann’s metaphysics allowed Hennig to ground some of the main theoretical principles of phylogenetic systematics, namely that the biological categories—from the semaphoront to the highest rank—have reality and individuality despite not being universals, and that they form a hierarchy of levels, each of which may require different kinds of explanation. Hartmann’s metaphysics thereby provided a philosophical justification for Hennig’s phylogenetic systematics, both as a theory and as a method of classification. (shrink)

During the early twentieth century, the Swiss Zoologist Adolf Naef (1883–1949) established himself as a leader in German comparative anatomy and higher level systematics. He is generally labeled an ‘idealistic morphologist’, although he himself called his research program ‘systematic morphology’. The idealistic morphology that flourished in German biology during the first half of the twentieth century was a rather heterogeneous movement, within which Adolf Naef worked out a special theoretical system of his own. Following a biographical sketch, we present an (...) English translation of a previously unpublished typescript from Naef’s estate, which Naef intended as the introduction to a textbook on Comparative Anatomy for which he was unable to find a publisher before his sudden death in 1949. The typescript contains Naef’s mature thoughts with unprecedented conciseness, focus, and clarity. The density of Naef’s text warrants a historical and contextual explication of its content. (shrink)

This paper takes a hierarchical approach to the question whether species are individuals or natural kinds. The thesis defended here is that species are spatiotemporally located complex wholes (individuals), that are composed of (i.e., include) causally interdependent parts, which collectively also instantiate a homeostatic property cluster (HPC) natural kind. Species may form open or closed genetic systems that are dynamic in nature, that have fuzzy boundaries due to the processual nature of speciation, that may have leaky boundaries as is manifest (...) in lateral gene transfer and introgression, that may be of multiple origins through hybridization, and that may split and merge and split again over time. The identity conditions of species qua individuals will have to be anchored in their history, rather than in their unique evolutionary origin. Species qua historically conditioned HPC natural kinds requires the kind to be mereologically structured, subject to the part-whole relation rather than the membership relation. This implies that there can be more than one kind of natural kinds. (shrink)

The relatively late acceptance of Darwinism in German biology and paleontology is frequently attributed to a lingering of Lamarckism, a persisting influence of German idealistic Naturphilosophie and Goethean romanticism. These factors are largely held responsible for the vitalism underlying theories of saltational and orthogenetic evolutionary change that characterize the writings of many German paleontologists during the first half of the 20th century. A prominent exponent of that tradition was Karl Beurlen, who is credited with having been the first German paleontologist (...) to present a full-fledged theory of saltational evolution and orthogenetic change. A review of Beurlen's writings reveals motives and concerns far more complex, however, and firmly rooted in contemporary völkisch thought and Aryan Science. Beurlen's mature theory of evolution can indeed be understood as his own contribution to Aryan Geology and Biology, tainted as it was with National-Socialist ideology. Evolutionary biologists of the time who opposed the theories of Beurlen and likeminded authors, i.e., idealistic morphology, typology, saltational change, orthogenesis and cyclism did so on Darwinian principles, which ultimately prevailed. But at the time when the battle was fought, their adherence to the principle of natural selection was likewise ideologically tainted, namely in terms of racial theory. National-Socialist ideology was unable to forge a unity of evolutionary theory in Germany even amongst those of its proponents who endorsed this ideology. (shrink)

The aim of this article is to detail some reservations against the beliefs, claims, or presuppositions that current essentialist natural kind concepts (including homeostatic property cluster kinds) model grouping practices in the life sciences accurately and generally. Such concepts fit reasoning into particular preconceived epistemic and semantic patterns. The ability of these patterns to fit scientific practice is often argued in support of homeostatic property cluster accounts, yet there are reasons to think that in the life sciences kind concepts exhibit (...) a diversity of grouping practices that are flattened out by conceptualizing them as natural kinds. Instead this article argues that the process of understanding grouping practices needs to start from a more neutral position independent of any ontological account. Following Love (Acta Biotheor 57:51–75, 2009) this paper suggests that typical natural kind concepts should be broached in the first place as grouping strategies that use a variety of semantic and epistemic tactics to apply group-bound information to tasks of explanation and understanding. (shrink)

This article, which is intended both as a position paper in the philosophical debate on natural kinds and as the guest editorial to this thematic issue, takes up the challenge posed by Ian Hacking in his paper, “Natural Kinds: Rosy Dawn, Scholastic Twilight.” Whereas a straightforward interpretation of that paper suggests that according to Hacking the concept of natural kinds should be abandoned, both in the philosophy of science and in philosophy more generally, we suggest that an alternative and less (...) fatalistic reading is also possible. We argue that abandoning the concept of natural kinds would be premature, as it still can do important work. Our concern is with the situation in the (philosophy of the) life sciences. Against the background of this concern we attempt to set something of an agenda for future research on the topic of natural kinds in the (philosophy of the) life sciences. (shrink)