ORIGIN OF SPECIES. INTRODUCTION. When on board HMS 'Beagle,' as naturalist, I was ranch struck with certain facts in the distribution of the organic beings ...

... Difficulty of distinguishing between Varieties and Species — Origin of Domestic ... and Origin— Principle of Selection anciently followed, its Effects— ...

(2003). Whewell's Philosophy of Discovery and the Archetype of the Vertebrate Skeleton: The Role of German Philosophy of Science in Richard Owen's Biology. Annals of Science: Vol. 60, No. 1, pp. 39-61.

This article argues that at least very many judgments of homology rest on prior attributions of selected‐effect (SE) function, and that many of the “parts” of biological systems that are rightly classified as homologous are constituted by (are so classified in virtue of) their consequence etiologies. We claim that SE functions are often used in the prior identification of the parts deemed to be homologous and are often used to differentiate more restricted homologous kinds within less restricted ones. In doing (...) so, we discuss recent criticism of this view that has been offered (especially that offered by Paul Griffiths). *Received July 2007; revised November 2008. †To contact the authors, please write to: Department of Philosophy, 201 West Duke Building, Box 90743, Durham, NC 27708; e‐mail: [email protected] or [email protected]. (shrink)

Philosophical discussions of biological classification have failed to recognise the central role of homology in the classification of biological parts and processes. One reason for this is a misunderstanding of the relationship between judgments of homology and the core explanatory theories of biology. The textbook characterisation of homology as identity by descent is commonly regarded as a definition. I suggest instead that it is one of several attempts to explain the phenomena of homology. Twenty years ago the ‘new experimentalist’ movement (...) in philosophy of science drew attention to the fact that many experimental phenomena have a ‘life of their own’: the conviction that they are real is not dependent on the theories used to characterise and explain them. I suggest that something similar can be true of descriptive phenomena, and that many homologies are phenomena of this kind. As a result the descriptive biology of form and function has a life of its own—a degree of epistemological independence from the theories that explain form and function. I also suggest that the two major ‘homology concepts’ in contemporary biology, usually seen as two competing definitions, are in reality complementary elements of the biological explanation of homology. (shrink)

Homology is a natural kind term and a precise account of what homology is has to come out of theories about the role of homologues in evolution and development. Definitions of homology are discussed with respect to the question as to whether they are able to give a non-circular account of the correspondence or sameness referred to by homology. It is argued that standard accounts tie homology to operational criteria or specific research projects, but are not yet able to offer (...) a concept of homology that does not presuppose a version of homology or a comparable notion of sameness. This is the case for phylogenetic definitions that trace structures back to the common ancestor as well as for developmental approaches such as Wagner's biological homology concept. In contrast, molecular homology is able to offer a definition of homology in genes and proteins that explicates homology by reference to more basic notions. Molecular correspondence originates by means of specific features of causal processes. It is speculated that further understanding of morphogenesis might enable biologists to give a theoretically deeper definition of homology along similar lines: an account which makes reference to the concrete mechanisms that operate in organisms. (shrink)