Content area
Full Text
Biol Philos (2012) 27:381400
DOI 10.1007/s10539-012-9313-7
Marc Ereshefsky
Received: 13 July 2011 / Accepted: 15 February 2012 / Published online: 10 March 2012 Springer Science+Business Media B.V. 2012
Abstract This paper explores an important type of biological explanation called homology thinking. Homology thinking explains the properties of a homologue by citing the history of a homologue. Homology thinking is signicant in several ways. First, it offers more detailed explanations of biological phenomena than corresponding analogy explanations. Second, it provides an important explanation of character similarity and difference. Third, homology thinking offers a promising account of multiple realizability in biology.
Keywords Historical explanation Historicity Homology Homology thinking
Multiple realizability Reductionism
Introduction
Homology is a familiar term in biology, but given what prominent biologists say about it perhaps we underestimate its importance. Darwin (1887: 233) writes that homology clears away the mist from such terms as the scheme of nature, ideal types, archetypal patterns or ideas, &c. Gould (1986: 60) talks about evolution and the triumph of homology. Wake (1994: 284) tells us that homology is the central concept for all of biology. What is so signicant about homology that would justify such claims?
Perhaps its importance is due to the fact that all useful comparisons in biology depend on the relation of homology (Patterson 1987: 18). Whenever we ask if two characters are the same character, whether they are genetic, morphological, or behavioral, we are asking if they are homologous. That speaks to the centrality of
M. Ereshefsky (&)
Department of Philosophy, University of Calgary, 2500 University Drive, NW, Calgary, AB T2N 1N4, Canadae-mail: [email protected]
Homology thinking
123
382 M. Ereshefsky
homology in biology. Still, there is something else important about homology. Gould (1986: 60) suggests that [Darwins] theory taught us the importance of history, expressed as the triumph of homology over other causes of order.
Goulds point is twofold. Darwins use of homology ushered in a signicant way of understanding biological phenomena. Furthermore, that way of understanding biological phenomena turns on the historicity of homologues. Let us call this way of understanding biological phenomena homology thinking to echo Mayrs (1959) phrase population thinking.1 Population thinking cites the structure of a population to explain the properties of a population. Homology thinking cites a characters history...