Species as family resemblance concepts: The (dis‐)solution of the species problem?

Abstract

SummaryThe so-called ''species problem'' has plagued evolutionary biology since before Darwin's publication of the aptly titled Origin of Species. Many biologists think the problem is just a matter of semantics; others complain that it will not be solved until we have more empirical data. Yet, we don't seem to be able to escape discussing it and teaching seminars about it. In this paper, I briefly examine the main themes of the biological and philosophical literatures on the species problem, focusing on identifying common threads as well as relevant differences. I then argue two fundamental points. First, the species problem is not primarily an empirical one, but it is rather fraught with philosophical questions that require-but cannot be settled by-empirical evidence. Second, the (dis-)solution lies in explicitly adopting Wittgenstein's idea of ''family resemblance'' or cluster concepts, and to consider species as an example of such concepts. This solution has several attractive features, including bringing together apparently diverging themes of discussion among biologists and philosophers. The current proposal is conceptually independent (though not incompatible) with the pluralist approach to the species problem advocated by Mishler, Donoghue, Kitcher and Dupré , which implies that distinct aspects of the species question need to be emphasized depending on the goals of the researcher. From the biological literature, the concept of species that most closely matches the philosophical discussion presented here is Templeton's cohesion idea.

Conceptualizing power to study social-ecological interactions

“…To avoid a perhaps impossible search for a quintessential definition of power (Connolly 1983), scholars now prefer to use Wittgenstein's idea of "family resemblance" (Wittgenstein 2006(Wittgenstein [1953, Haugaard 2012) to advocate a plural view that acknowledges power as a cluster of several related but distinct Ecology and Society 21(1): 21 http://www.ecologyandsociety.org/vol21/iss1/art21/ aspects (Allen 1999, Morriss 2002, Dowding 2012, Haugaard 2012. Dimensions and sources of power are thus understood as a cluster of characteristics: a family in which members share some traits but no one trait identifies the family as distinct from others (Pigliucci 2003). The traits are not mutually exclusive, but rather presuppose each other.…”

Virus species polemics: 14 senior virologists oppose a proposed change to the ICTV definition of virus species

“…In the context of viral taxonomy, however, there is no ambiguity at all, since the term has been defined in numerous publications [3,13,14,17]. Recently it has been proposed that the term ''polythetic class'' in the species definition could be replaced by ''cluster class'' which is a more easily understood synonym widely used in taxonomy [18,19]. However, judging from the comments of King et al as well as some comments posted in response to their proposal, it seems unlikely that the objections to using the term polythetic class in the species definition would disappear if the term were replaced by ''cluster class''.…”

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“…Interestingly, the model also evolved 'parasites' which not only were able to coexist with catalytic molecules, but in turn were themselves catalysts for the evolution of further complexity in the system. While Takeuchi & Hogeweg's (2008) definition of species in this context may appear artificial, the group of genotypes they identified are in fact both ecologically functionally distinct and genealogically related to each other, and a functionalgenealogical concept is certainly one of the viable contenders as a definition of biological species (Pigliucci 2003).…”