Thomas Henry Huxley and Charles Darwin discovered in 1857 that they had a fundamental disagreement about biological classification. Darwin believed that the natural system should express genealogy while Huxley insisted that classification must stand on its own basis, independent of evolution. Darwin used human races as a model for his view. This private and long-forgotten dispute exposes important divisions within Victorian biology. Huxley, trained in physiology and anatomy, was a professional biologist while Darwin was a gentleman naturalist. Huxley agreed with (...) John Stuart Mill's rejection of William Whewell's sympathy for Linnaeus. The naturalists William Sharp Macleay, Hugh Strickland, and George Waterhouse worked to distinguish two kinds of relationship, affinity and analogy. Darwin believed that his theory could explain the difference. Richard Owen introduced the distinction between homology and analogy to anatomists, but the word homology did not enter Darwin's vocabulary until 1848, when he used the morphological concept of archetype in his work on Cirripedia. Huxley dropped the word archetype when Richard Owen linked it to Plato's ideal forms, replacing it with common plan. When Darwin wrote in the Origin of Species that the word plan gives no explanation, he may have had Huxley in mind. Darwin's preposterous story in the Origin about a bear giving birth to a kangaroo, which he dropped in the second edition, was in fact aimed at Huxley. (shrink)

A dominant strand of philosophical thought holds that natural kinds are clusters of objects with shared properties. Cluster theories of natural kinds are often taken to be a late twentieth-century development, prompted by dissatisfaction with essentialism in philosophy of biology. I will argue here, however, that a cluster theory of kinds had actually been formulated by William Whewell (1794-1866) more than a century earlier. Cluster theories of kinds can be characterized in terms of three central commitments, all of which are (...) present in Whewell’s work on classification. Like contemporary cluster theorists, Whewell claims that kinds are united by similarity, that many kinds do not have essences, and that there are “gaps” between kinds. Moreover, Whewell advises taxonomists to look for consilience (roughly, convergence) between different classificatory schemes, a recommendation that reinforces the identification of natural classes with property clusters. Thus Whewell was not only an early cluster theorist, but one with important insights into what a cluster theory of kinds means for the practice of classification. (shrink)

In 1847, the British polymath William Whewell pointed out that the sciences for which he, in 1837, had coined the term “palætiological” have much in common and that they may reflect light upon each other by being treated together. This recommendation is here put into practice in a specific way, to wit, not by comparing the palaetiological sciences that Whewell distinguished himself but by comparing the general historical development of the scientific study of the four broad palætiological domains that he (...) enumerated in 1847: the solar system, the Earth, its vegetable and animal creation, and man. For wide and various as their subjects are, it will be found that [the palætiological sciences] have all certain principles, maxims, and rules of procedure in common; and thus may reflect light upon each other by being treated together. William Whewell ( 1847, 1, p. 640). (shrink)

The term “cladist” has distinct meanings in distinct contexts. Communication between philosophers, historians, and biologists has been hindered by different understandings of the term in various contexts. In this paper I trace historical and conceptual connections between several broadly distinct senses of the term “cladist”. I propose seven specific definitions that capture distinct contemporary uses. This serves to disambiguate some cases where the meaning is unclear, and will help resolve apparent disagreements that in fact result from conflicting understandings of the (...) term. (shrink)

In this paper I sketch William Whewell’s attempts to impose order on classificatory mineralogy, which was in Whewell’s day (1794e1866) a confused science of uncertain prospects. Whewell argued that progress was impeded by the crude reductionist assumption that all macroproperties of crystals could be straightforwardly explained by reference to the crystals’ chemical constituents. By comparison with biological classification, Whewell proposed methodological reforms that he claimed would lead to a natural classification of minerals, which in turn would support advances in causal (...) understanding of the properties of minerals. Whewell’s comparison to successful biological classification is particularly striking given that classificatory biologists did not share an understanding of the causal structure underlying the natural classification of life (the common descent with modification of all organisms). Whewell’s key proposed methodological reform is consideration of multiple, distinct principles of classification. The most powerful evidence in support of a natural classificatory claim is the consilience of claims arrived at through distinct lines of reasoning, rooted in distinct conceptual approaches to the target objects. Mineralogists must consider not only elemental composition and chemical affinities, but also symmetry and polarity. Geometrical properties are central to what makes an individual mineral the type of mineral that it is. In Whewell’s view, function and organization jointly define life, and so are the keys to understanding what makes an organism the type of organism that it is. I explain the relationship between Whewell’s teleological account of life and his natural theology. I conclude with brief comments about the importance of Whewell’s classificatory theory for the further development of his philosophy of science and in particular his account of consilience. (shrink)