Naming and contingency: the type method of biological taxonomy

Abstract

Biological taxonomists rely on the so-called 'type method' to regulate taxonomic nomenclature. For each newfound taxon, they lay down a 'type specimen' that carries with it the name of the taxon it belongs to. Even if a taxon's circumscription is unknown and/or subject to change, it remains a necessary truth that the taxon's type specimen falls within its boundaries. Philosophers have noted some time ago that this naming practice is in line with the causal theory of reference and its central notion of rigid designation: a type specimen fixes the reference of a taxon name without defining it. Recently, however, this consensus has come under pressure in the pages of this journal. In a series of articles by Alex Levine, Joseph LaPorte, and Matthew Haber, it has been argued that type specimens belong only contingently to their species, and that this may bode problems for the relation between type method and causal theory. I will argue that this 'contingency debate' is a debate gone wrong, and that none of the arguments in defense of contingency withstand scrutiny. Taxonomic naming is not out of step with the causal theory, but conforms to it. However, I will also argue that this observation is itself in need of further explanation, since application of the type method in taxonomic practice is plagued by errors and ambiguities that threaten it with breaking down. Thus, the real question becomes why taxonomic naming conforms to the causal theory in the first place. I will show that the answer lies in the embedding of the type method into elaborate codes of nomenclature. * This version is identical to the published version, available at http://dx.doi.org/10. 1007/s10539-014-9459-6. Earlier versions of this paper were presented at ISHPSSB 2013 in Montpellier, PBUK 2014 in Cambridge, and Utrecht University. I am grateful to these audiences for helpful feedback. Two anonymous reviewers, Matt Haber, Michael Devitt, and (especially) Kim Sterelny provided many thoughtful comments on earlier versions of the manuscript.

Suppressing Synonymy with a Homonym: The Emergence of the Nomenclatural Type Concept in Nineteenth Century Natural History

“…Existing classifications were disrupted, and in the waves of change taxon names became afloat; 61 The notion of a 'neotype' raises further philosophical issues. For discussion of these intricacies, see Simpson (1945), Haber (2012) and Witteveen (2015). 62 Meanwhile, Simpson himself continued to correct confused (or careless) taxonomists who wrote things like ''the closer the description [of the species] comes to fitting the holotype exactly, the better the picture one can obtain of the typical specimen of the species'' (Shenefelt, 1959).…”

Names are not good enough: Reasoning over taxonomic change in the Andropogon complex1

“…The reasons for this insufficiency are systemic and well known to taxonomy contributors and users [3,10,66,74]. Ultimately they are rooted in the way in which identity is established according to the rules of nomenclature that guide the application of names to perceived taxonomic groups [29,51,64,96].…”

“…Typically both a type and a feature-based circumscription are provided when anchoring the meaning (referential extension) of a taxonomic name [29,34,37,96]. However, the former arbiter -i.e., the type identity -has special weight when dealing with alternative name:meaning (read: "name-to-meaning") assignments that become necessary when taxonomies undergo revisions.…”

Objectivity, Historicity, Taxonomy

“…Since the type method defines ''type specimen'' as ''the name-bearer for the species it belongs to,'' a type specimen for a certain species name cannot fail to belong to the species it names, no matter how flawed the accompanying description may turn out to be. 7 In other words, a type specimen necessarily belongs to the species it names (Hull 1982;Witteveen 2015;Ereshefsky 2007). The second disanalogy Daston draws attention to, involves the widely held metaphysical view that species are large-scale individuals rather than sets, classes, or kinds.…”

“…The reason one part is better than several is simple: modern-day type specimens do not help to define or reconstruct species, but only serve to fix the 6 A more elaborate account of taxonomic names as rigid designators requires an excursion into possible worlds. I do not have the space to discuss this background here, but for detailed treatments see Haber (2012), Witteveen (2015). 7 Daston cites a particular article of a particular code of nomenclature in support of her point: Article 7.4 of the The International Code of Botanical Nomenclature (Greuter et al 2000).…”