How To Misidentify A Type Specimen Matthew H. Haber Abstract Type specimens are used to designate species. What is the nature of the relation between a type specimen and the species it designates? If species names are rigid designators, and type specimens ostensively define species, then that relation is, at the very least, a close one. Levine (2001) argues that the relationship of type specimen to a named species is one of necessity—and that this presents problems for the individuality thesis. Namely, it seems odd that a contingently selected specimen should belong to a species of necessity. In considering Levine’s argument, LaPorte (2003) suggests that recognizing the distinction between de re and de dicto necessity resolves Levine’s worries. I reconsider the motivating question: does a type specimen belong of necessity to the species that it designates? In light of taxonomic cases and practice the answer is clear: definitively not. This is particularly clear in the case of re-designation of types by taxonomic decree. I explain how this impacts both Levine and LaPorte’s arguments, helps reveal how taxonomists prioritize competing (and sometimes conflicting) theoretical commitments, and offer a defense of the individuality thesis as applied to these particular cases. In short, I demonstrate how to misidentify a type specimen.

Contents 1 Introduction

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2 Naming and Taxonomic Necessity 2.1 The contingency problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 de re and de dicto Taxonomic Necessity . . . . . . . . . . . . . . . . . . . .

2 5 6

3 How To Misidentify A Type Specimen 3.1 Misidentification By Priority . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Misidentification and Re-designation of Types . . . . . . . . . . . . . . . . .

7 9 11

4 Conclusion

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1

Introduction

In the late 1990’s a minor taxonomic scuffle arose over the endangered San Francisco Garter Snake (Thamnophis sirtalis tetrataenia, Cope in Yarrow 1875), and the common California Red-Sided Garter Snake (Thamnophis sirtalis infernalis, de Blainville 1835). Researchers discovered that T.s.infernalis’ type specimen belonged to T.s.tetrataenia (Boundy and Rossman 1995; Barry et al. 1996). Typically in such cases the taxa would be re-named. The codes of taxonomic nomenclature are clear on this, with rules specifying just how to handle such cases, e.g., the principles of priority and typification (ICZN 1999, Art. 23, 61). In this case, though, a petition was submitted to ICZN requesting that the names be conserved for each taxon in question. The case was published (Barry and Jennings 1998), commentary solicited (Smith 1999), and a ruling issued (ICZN 2000): Opinion 1961 of the ICZN stated that new type specimens had been designated for each taxa, thus conserving prevailing usage of the names. Type specimens are used to designate species. What is the nature of the relation between a type specimen and the species it designates? If species names are rigid designators, and type specimens ostensively define species, then that relation is, at the very least, a close one. That a type specimen can be re-designated poses a threat to standard accounts of definition by type specimen and suggests that rigid designation and causal theory of reference may be more fragile than supposed. If that is right, it is disquieting to be sure. This is especially worrisome if we take biological nomenclature to be a good test case for theories of reference and proper names. I will argue that the the scope of this worry is limited, and only under particular complicating factors, e.g., when our theories about the boundaries of an individual are subject to regular revision or persistent debate. Furthermore, the worry is in part borne of a mistaken premise, that type specimens belong of necessity to the species they designate. I will argue, to the contrary, that type specimens belong only contingently to their species, and the modal force is constrained. Still, we should not dismiss cases of misidentification and re-designation of type specimens. Taxonomic theory is, in large part, a theory of reference applied to biological nomenclature. I explain how accounting for cases like that of T.s.infernalis help reveal complications that our theories and concepts of nomenclature ought to account for, along the way defending an interpretation of taxa as individuals. In short, I demonstrate how to misidentify a type specimen.

2

Naming and Taxonomic Necessity

A preliminary is in order. Rather than ask whether an organism is a member or part of a species, I will use the locution belongs to. Where the former imply set-theoretic, mereolog2

ical, or individuality approaches, I take belongs to to be neutral (or, perhaps, ambiguous) with regard to how an entity may belong to a group. Specifying (or disambiguating) the belongs to relation is just what is at stake in debates over the ontology of species, and prematurely specifying a locution does the discussion no good. Along the way I will make the case for an individuality thesis interpretation of belongs to; though this is not the primary aim here, shedding light on a thesis so central to systematics will help dispel some common misperceptions of it. Since the early 20th century, taxon names have been defined by way of type specimens,1 e.g., the referent of a species name is whatever species a designated type specimen belongs to.2 The type specimen is a physical specimen, and need not be typical of other organisms that belong to that species. Species are not defined in terms of any properties or characters a type specimen may possess, but solely by way of what species that type belongs to. This is codified in applicable nomenclatural codes, e.g., the International Code of Zoological Nomenclature (ICZN), Article 61 (The Principle of Typification) states that “the fixation of the name-bearing type of a nominal taxon provides the objective standard of reference for the application of the name it bears.” How, exactly, that reference is applied is a matter of taxonomic judgment.3 Independent of that judgment, taxon names bear on whatever taxon that type specimen belongs: Article 61.1.1.4 No matter how the boundaries of a . . . taxon may vary in the opinion of zoologists the valid name of such a taxon is determined . . . from the name-bearing type(s) considered to belong within those boundaries.5 One influential reading of definition by type specimen has been derived from Michael Ghiselin and David Hull’s individuality thesis (Ghiselin 1966, 1974, 1995; Hull 1976, 1978). In short, species names are understood as ostensively defined rigid designations of individuals, i.e., proper names, by many accounts (cf. Kripke 1980). Species are pointed at by way of a relevant part of that species, namely, by pointing at the type specimen. The naming act is documented by publication in a prescribed format as legislated in the relevant code of nomenclature, and the type specimen carefully preserved (typically in a museum) as an artifact of this ostensive act. This explains both how a species name gets its meaning, and how competent usage is evaluated. It appears a rather straight-forward example of the 1

Now called holotypes, lectotypes, or neotypes. For a practical guide to naming taxa see Winston (1999). A species is one kind of taxa. Other kinds of taxa are also defined by types, e.g., sub-species, genera and families. Most of the discussion here about species names will be generalizable to other taxa, though this leaves aside worries about higher taxa (Ereshefsky 2001). 3 This is informally described as the principle of taxonomic freedom (Haber man.). Roughly, this simply means that codes of nomenclature are silent on the criteria of belonging to a taxon, e.g., it is left to individual researchers to decide what species concept to apply to determine the taxonomic boundaries about a type specimen. 4 References to ‘Article #’ are to ICZN (1999) Articles. 5 In case of a taxon boundary including multiple type specimens, the principle of priority is applied [Art. 23]. More on this below. 2

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causal theory of reference (Putnam 1975; Kripke 1980). Levine (2001) has challenged this characterization of species names, arguing that two problems of inscrutability arise: what he calls the “qua-problem,” and the “contingencyproblem.” The qua-problem concerns the ambiguity of ostension by pointing; this will be left aside here.6 The contingency problem describes a paradox that arises from treating species as individuals and species names as ostensively defined rigid designations. On Levine’s account, type specimens belong both contingently and necessarily to the species that they designate. After all, a different specimen could have been designated as the type, yet the type necessarily belongs to the species that it identifies. This is deemed unacceptable, and taken as symptomatic of deeper conceptual problems. LaPorte (2003) considers Levine’s arguments, and, following Kripke, concludes that Levine fails to distinguish de re from de dicto necessity, and conflates a prioricity with necessity. LaPorte offers a solution to the contingency problem, i.e., while de dicto necessity may hold in these taxonomic cases, de re does not. Thus the problem is resolved. I accept LaPorte’s analysis of Levine, yet LaPorte does not go far enough. De dicto necessity only holds under idealized conditions—conditions that we know fail to hold when type specimens are re-designated. So though the relation between a type specimen and the species it identifies is a tight one, it is not a relation of necessity. In other words, both Levine and LaPorte are starting from a false premise. Types do not belong to their species of necessity, de dicto or otherwise. Our analyses of how names designate individuals must (and do) account for this, i.e., they must tell us how to misidentify a type specimen. To see why, let’s first get a better grip on Levine’s worry, and LaPorte’s response. 6 A quick response: I think this ambiguity is resolved by specification and application of relevant theoretical concepts, e.g., species concepts provide a means of specifying boundaries, dissolving the ambiguity Levine is concerned about. Speciality training includes learning how to correctly apply these concepts, and controversies persist about competing concepts. On the former, there may still be uncertainty about a taxon’s boundary in such cases, but this is generally an epistemic problem. Metaphysical and conceptual debates may also persist, as disagreements over which concepts ought to be adopted or how they ought to be applied. This disambiguation procedure generalizes over scientific practice, and offers a means by which entities may be specified precisely—or, at least, identifies the terms of ambiguity at stake and in conflict, e.g., debates over the largest organism may hinge upon the concept of organism specified as much as the empirical facts regarding the size of the biological entity in question (e.g., Smith et al. 1992; Brasier 1992). This is not to deny the qua-problem; something like it likely captures problems of unambiguously specifying higher (Linnaean) taxa. However, this is symptomatic of the lack of an underlying ontology or theory of higher taxa, and how this may undermine reference (Ereshefsky 2001). To my mind, this does not undermine treatment of species names as rigid designators, so much as supports a move away from traditional ranked-nomenclature and towards one that provides a more inclusive theoretical basis, e.g., phylogenetic nomenclature.

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2.1

The contingency problem

Levine (2001) succinctly and clearly describes what he dubs the contingency problem. In short, he describes a paradox that arises when we both accept the individuality thesis (that organisms are parts, not members of a species) and take species names to be rigid designators ostensively defined by type specimens. The consequence, argues Levine, is that type specimens end up belonging to the species that they designate both contingently and necessarily. Yet an entity can not belong both contingently and necessarily to something upon pain of contradiction. This is the contingency problem. The contingency problem applies only to type specimens, due to their special role as namebearer of the species which they designate. To see the problem, let’s accept, without argument, Levine’s premise that organisms belong to their species only contingently. I’ll call this the contingency clause. This may be understood in two ways. The first is to deny that species are defined extensionally by their organisms (Sober (1980) calls this a constituent definition). That is, a species’ identity would not change had it more or fewer organisms. On this assumption, species cannot be sets or mereological sums. These are defined extensionally, and carry different modal properties than do species as individuals.7 The second way to understand the contingency clause is that any given organism could have belonged to a different species, no species at all, or not have been born. Later I will return to both of these readings and provide an account of them in the individuality thesis. The contingency clause along with the interpretation of definition by type derived from the individuality thesis produces what at first appears to be a paradox. Namely, as the name-bearer, a type specimen appears to belong of necessity to the species it designates (ostensively defines); yet selection of that specimen as the type was a contingent fact, and on the contingency clause it belongs to its species only contingently. It appears that the type belongs to its species both of necessity and contingently. This is what Levine dubs the contingency problem. 7

One might ask what belongs to might mean if not framed in terms of set membership or mereological part-hood. This is a central (though often misunderstood) part of the individuality thesis, which takes the part/whole relation to be biological, not logical. For example, where mereological part-hood is transitive, biological part-hood may not be. This suggests the part/whole relation of logical individuals is not the same as of biological individuals, and each carry different modal implications—notably of when identity conditions will hold). Varzi (2006) distinguishes between (proper mereological) ‘parts’ and ‘φ-parts’, where φ is a predicate modifier that may generate a non-mereological part/whole relation. I’ll simply suggest here that ‘biological-part’ ought to be understood as a possible φ-part specified by biological theory that may have various complexities with regard to transitivity and the varying strength of belongs to, and is poorly analyzed in mereological terms. Ghiselin (1997, p. 40 and elsewhere) concurs, arguing that “Unfortunately the efforts of logicians . . . have not produced the sort of logic (mereology) that would seem useful for our purposes . . . . We need something that treats individuals as more than just the sums of their parts.” Elsewhere I have offered a brief account of how the biological part/whole relation ought to be construed (Haber ming), and will return to this below.

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2.2

de re and de dicto Taxonomic Necessity

LaPorte (2003) offers a compelling rebuttal to the contingency problem. Following Kripke, LaPorte demands a distinction between de re and de dicto necessity, and also that we not confuse a prioricity for certainty. Instead, LaPorte concludes that type specimens belong to the species they designate by de dicto but not de re necessity, and that these may be contingent a prior truths. LaPorte (p. 586) takes Levine’s claim of necessity to be that: It is necessary that any species with a type specimen contains its type specimen; and recognizes that both a de dicto and de re reading are available: de dicto: Necessarily, any species with a type specimen contains its type specimen; de re: Any species with a type specimen necessarily contains its type specimen. Let’s formalize these:8 Txy: x is y’s type specimen; Bxy: x belongs to y. de dicto : �∀y∀x(T xy ⊃ Bxy) de re : ∀y∀x(T xy ⊃ �Bxy)

(1) (2)

. . . and render them thusly: de dicto: Necessarily, all type specimens belong to their species; de re: All type specimens necessarily belong to their species. My renderings are constructed slightly different than LaPorte’s, but express the same underlying claim while clarifying the truth conditions of each. (Later I will demonstrate how the de dicto reading fails, and my rendering will make that more clear.) 8

Two quick notes on my formalization. (1) I am treating species as individuals, rather than kinds (or, more precisely, predicates). This is both because that is part of what is being evaluated, and also because I hold the view that species are individuals. Still, I recognize it may be unusual to see particular species falling under the scope of predicates, as opposed to simply being predicates. My own preference is to treat species as falling within the scope of relations like these, regardless of whether they are conceived of as individuals, kinds, sums, sets, etc. I acknowledge this is a non-standard view (but see Jubien 2009). Anyways, it is easy enough to re-formulate these treating species as predicates, e.g., �∀x(T x ⊃ Bx) and ∀x(T x ⊃ �Bx). (2) Belongs to is approximated and poorly captured by formal logic relations. This was briefly touched on above, but bears repeating. I take belongs to to capture the biological part/whole relation specified by biological theories, concepts, practice, data, etc. One reason it is poorly captured by logical relations is that a biological part/whole relation may be stronger or weaker, producing a gradient along which something may belong to a biological object. This sort of gradient belonging to is not captured well by the categorical belonging to typically rendered in logic.

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Distinguishing de dicto and de re necessity provides LaPorte access to resources in causal theories of reference and rigid designation that resolve the contingency problem. Namely, LaPorte argues that Levine is guilty of conflating de dicto and de re necessity, where the latter is false the former true: The de dicto sentence ‘Necessarily, any species with a type specimen contains its type specimen’ is true if and only if, with respect to any possible world, the following statement is true (as we use the statement in the actual world): ‘Any species with a type specimen contains its type specimen’. This does seem to be true in any possible world: take any world, and if in that world a species has a type specimen, then in that world the species contains the type specimen. The de re sentence ‘Any species with a type specimen necessarily contains its type specimen’ is true if and only if any species with a type specimen in the actual world contains that very type specimen in every possible world. This reading does not seem to be true. Rover serves as a type specimen for Canis familiaris in the actual world but there are worlds in which he is not in Canis familiaris, never having been born. It is contingent, not necessary, that Canis familiaris contains Rover. (LaPorte 2003, p. 587) So though the sentence ‘Type specimen x belongs to species Xus yus’ is contingently true, on LaPorte’s analysis it expresses a de dicto necessary truth, and explains how we might come to know this with a priori certainty. LaPorte rightly notes this is analogous to Kripke’s well known treatment of sentences like, ‘The length of one meter is instantiated by stick S’, where S is the standard meter stick: “Similarly, even if we define what a meter is by reference to the standard meter stick, it will be a contingent truth and not a necessary one that that particular stick is one meter long” (Kripke 1980, p. 75). LaPorte’s resolution is satisfying and elegant in the way it connects core analytic philosophy with taxonomy and philosophy of biology. I accept his argument, yet in a deeply important sense it goes wrong. Namely, not even de dicto necessity holds here. Understanding why, and how this is accounted for, sheds light on taxonomic philosophy, scientific practice, the individuality thesis, ostensively defined rigid designators, and the causal theory of reference.

3

How To Misidentify A Type Specimen

I asserted above that not even de dicto necessity holds between a name-bearing type and the species it designates. If species names are rigid designators ostensively defined by type specimens, this is a surprising (and possibly troubling) result. In this section I describe two ways a type specimen may be misidentified—thus demonstrating how the modal force

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of both de dicto and de re necessity fail. A little set up will help. Consider the following passage: Taxonomy is error-prone, and what is thought to be a properly discrete species may turn out not to be. But even if the species membership of a type specimen is reassigned, the new species must bear the name originally assigned to the specimen. So, even though the species membership of a type specimen is both contingent and uncertain, the relation between the specimen and the species name it bears is both necessary and certain. (Levine 2001, p. 334, emphasis added) Several unstated premises are lurking here which entail commitments that will be useful to discharge. For example, belongs to is being interpreted as “membership”, suggesting an extensional treatment of species.9 This is evident in describing the “reassignment” of the type specimen to a “new species” based on new taxonomic boundaries. This is incorrect. On the codes of nomenclature, the hypothesis of the taxonomic boundaries of a species have been revised. More (or fewer, or different) organisms are now thought to be included in those boundaries. On an extensional definition of species (“membership”), the identity of that species has changed: if under the two hypotheses the species has different members, then we really are discussing different species.10 Rejecting an extensional definition here allows that a species’ identity may persist across such changes. In this case, we were simply wrong about the composition of that species, i.e., what belongs to it. This is not merely an epistemic issue, but also a modal and temporal claim about how the composition of a species relates to its identity conditions.11 Definition by type entails that species Xus yus just is whatever species its type belongs to. The identity conditions of Xus yus are not tied to a particular composition of organisms.12 The modal properties of species defined by type come apart from those defined extensionally. Sober (1984) makes a similar point 9 Alternatively, “membership” may entail the treatment of species as natural kinds. This is a slightly different issue, though closely related and often conflated with how to disambiguate belongs to. For various reasons, I prefer my interpretation of Levine’s usage, e.g., his stated aim includes the evaluation of the individuality thesis, and adopting a kinds view here undermines that goal. Like many others, Levine appears to be taking the individuality thesis to imply a constituent (i.e., extensional) definition, and so is likely taking his formulation as neutral (though it is not). In other words, though constituent definitions often accompany a natural kinds treatment of species, they need not. Regardless, taking “membership” to imply natural kinds also entails a complicated set of commitments, which I would argue should be similarly discharged. 10 Notice how easy it is to generate taxonomic incommensurability on an extensional definition of species. Given the priority placed on the principle of stability in nomenclatural codes, it should hardly be surprising that taxonomists tend to reject constituent (or extensional) definitions in favor of population (and phylogenetic) thinking. 11 The individuality thesis makes this explicit, one reason I favor it. 12 Or, if you prefer the natural kinds interpretation of “membership”, this can be re-formulated as something like, “the identity conditions of Xus yus are not tied to possession of an essential property, some set of properties, or distribution of variation of those properties.”

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in response to Kitcher (1984), though Kitcher persists in treating the species as individuals thesis as a claim about mereology (see Kitcher 1987). This analysis of Levine’s passage is not merely pedantic. When identity conditions hold is of central importance in this discussion; to specify that is to specify the relevant modal properties of species and their type specimens. As specified above (and in the codes), the identity conditions of a species are determined by what species its type specimen belongs to. Characters, composition and the like are irrelevant to identity conditions (though perhaps epistemically useful); all that matters is whether an organism and the type specimen stand in the relation, belongs to the same species as (where this is specified by taxonomic theory). On either version of the contingency clause, and as described by Levine and LaPorte, those identity conditions do not satisfy de re necessity, i.e., “all type specimens necessarily belong to their species” fails; e.g., there are possible worlds in which a different type specimen was selected, or where the actual type specimen was never born or belonged to a different species. Both Levine and LaPorte agree, presumably, that de dicto necessity holds, “Necessarily, all type specimens belong to their species.” That is, in any possible world, the type specimen of a species belongs to it. This limits the modal scope of a specific type/species relation to within a world, rather than across them. But Levine and LaPorte are wrong. de dicto necessity fails, and it fails in the actual world. This happens every time a type specimen is misidentified—something that should not be possible if type specimens belong to their species of de dicto necessity. Analyzing the passage above identifies what is at stake and criteria for what counts as a misidentification of a type specimen. Namely, identity conditions must be genuinely disrupted for the type specimen, but not for the designated species. Below I will describe two ways this may occur. One way is misidentification by priority, i.e., cases of taxonomic revision where a species ends up containing multiple type specimens. This is fairly common, and requires that one type be suppressed and lose its type status. Though this may be a vacuous misidentification, it demonstrates how a type specimen may only contingently belong to its species. The second kind of misidentification was introduced at the start of this paper in the case of T.s.infernalis. These are cases in which a new type (i.e., a neotype) is designated, and the old one no longer recognized as belonging to the species it designated. Though not frequent, this is common enough to give pause to assertions of de dicto necessity.

3.1

Misidentification By Priority

Taxonomic hypotheses are subject to revision. As hypotheses of taxonomic boundaries are revised, a different group of organisms may be taken to belong to a species. This

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may result in a species including two type specimens, e.g., if two species formerly thought distinct are discovered to be one. In this case, the principle of priority [Art. 23] is invoked, and the oldest available taxon name applies. Names attached to other type specimens are suppressed and reserved as junior synonyms, unavailable for use for other taxa. Something rather subtle is worth drawing out here. What was a type specimen is no longer one, though suppressing and reserving the name that type was bearing reserves that the specimen may yet again be elevated to type status (e.g., if taxonomic boundaries are further revised, leaving that specimen as the senior type under the new taxonomic hypothesis). So type specimens may lose their status as types, and belong only contingently to a species. This is akin to discovering that someone had been previously named. Consider Levine’s example: Suppose Aristotle is named ‘Aristotle’ in virtue of the coupling of his father’s first utterance of the name, together with his ostensive contact with the boy’s left ear. (Levine 2001, p. 335) Were it revealed that Aristotle’s mother had previously named him ‘Theseus’ by ostensive contact with his right little toe, then, under something akin to ICZN rules, Aristotle’s name would have been ‘Theseus’, and ‘Aristotle’ suppressed in case it was discovered that his left ear and right little toe did not belong to the same person. It’s relevant, I think, that we typically have very little difficulty delineating the boundaries of a person, and quite a bit with species. There are both epistemic and conceptual/theoretical reasons for this. Identifying the boundaries of a species may fall prey to lack of good data, or disagreement over what constitutes a species boundary in the first place, among other reasons. Human boundaries tend to be more accessible to us via direct observation. Conceptual issues, obviously, can complicate matters. Philosophers are certainly familiar with cases regarding when a person begins or ends, or under what conditions personal identity persists. More recently, what parts belong to a human, and how these impact both identity conditions and individuation further complicate matters (Dupr´e 2010).13 Suppression of types might not undermine de dicto necessity. Losing status as a type specimen means that a specimen is no longer an active name-bearer. That function has been suppressed, though may be re-activated. However, it may be that the specimen still belongs of necessity to the species it ostensively designates, yet this holds only vacuously when no such species is designated. In such cases the specimen is merely a specimen, and no longer a type, so the claim of necessity no longer applies (or applies only vacuously). So necessity is only contingent, though contingency here extends deeper than in Kripke’s 13 A fascinating example of this is human tetragametic chimerism (Yu et al. 2002). This occurs when two separate ova are fertilized by distinct sperm, yet rather than developing into fraternal twins the zygotes end up fusing. The result is a person born with two distinct gametic cells lines, i.e., congenital chimerism.

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meter stick case. That we might discover that an individual species species had a different type specimen violates the modal force Kripke assigns to scientific kinds. We might discover that something else caused the phenomenon we call heat, but heat cannot be anything but the kinetic movement of molecules (Kripke 1980, p. 130-32). The difference is that we might discover that we were referring to a different scientific kind, whereas here a species’ identity does not change, only that we were wrong about its boundaries. Of course, this is because Kripke adopts an essentialism about natural kinds. Following Ghiselin and Hull (and others), I take species to be individuals, and not kinds, and reject essentialism (cf. Sober 1980; Ereshefsky 2010). That a type specimen (or representative sample) may be misidentified and suppressed supports this view; Kripkean kind essentialism denies this, and simply does not apply to species. We might still ask whether the vacuous necessity described here generates the contingency problem. I do not think it does. After all, a vacuous necessity like this seems hardly to be a necessity at all. It’s akin to stating that a proposition is necessarily true except when it isn’t. The modal force of this vacuous necessity is too weak to generate the contingency problem. Let’s leave aside, though, how the principle of priority undermines de dicto necessity, and assume that it can be accounted for rather easily, either by the vacuity move described here or some other similar sort of response. A more serious challenge to de dicto necessity are neotypes and cases like that of T.s.infernalis described above.

3.2

Misidentification and Re-designation of Types

Let’s recap the case of T.s.infernalis. Barry and Jennings (1998) appealed to the ICZN, where neotypes are defined as: Article 75 (Neotypes) A neotype is the name-bearing type of a nominal species-group taxon designated under conditions specified in this Article when no name-bearing type specimen (i.e. holotype, lectotype, syntype or prior neotype) is believed to be extant and an author considers that a name-bearing type is necessary to define the nominal taxon objectively. Though a name-bearing type specimen was extant in this case, Article 75 provides other conditions under which a neotype may be designated. Specifically, they appealed to: Article 75.6 (Conservation of prevailing usage by a neotype) When an author discovers that the existing name-bearing type of a nominal species-group taxon is not in taxonomic accord with the prevailing usage of names and stability or universality is threatened thereby, he or she should maintain prevailing usage [Art. 82] and request the Commission to set aside under its plenary power [Art. 81] the existing name-bearing type and designate a neotype. 11

Simply put, this Article is invoked when a type specimen has been misidentified, and a new type must be designated for the species in question. In this case, researchers discovered that the type specimen of the common California RedSided Garter Snake (T.s.infernalis, de Blainville 1835) was a San Francisco Garter Snake (T.s.tetrataenia, Cope, E.D. in Yarrow, H.C. 1875) (Boundy and Rossman 1995; Barry et al. 1996). This is an example of failure of accordance between type specimen and species. Typically, and by default, this is resolved by treating the type specimen as the name-bearer of the species, and finding a new type species for the misidentified species, i.e., misidentification is located on the nominal taxon, not the type specimen. Here the San Francisco Garter Snake would be re-named T.s.tetrataenia, and the California Red-Sided Garter Snake would need to be re-named, as its name was no longer available (Boundy and Rossman 1995). This follows straight-forwardly from the principles of priority and typification [Art. 23, 61]. Here, though, researchers filed a petition with the ICZN under Article 75.6 to (i) conserve prevailing usage, (ii) designate a new type specimen (a neotype), and (iii) set aside the existing type specimen. T.s.infernalis is a common species, found across California. T.s.tetrataenia is an endangered and protected species, primarily geographically limited to San Mateo County, California. Re-naming it T.s.infernalis would carry severe conservation implications, as the name T.s.tetrataenia had been used for the San Francisco Garter Snake in all government documents concerning conservation (Barry et al. 1996). Indeed consistent and persistent usage of the name easily predates the United States Endangered Species Act, under which it is protected. That is, they made the case that current usage of T.s.tetrataenia and T.s.infernalis reflected long-standing, stable, and universal usage of those names, and that name changes threatened to be deeply disruptive. The petition was published in the Bulletin of Zoological Nomenclature (Barry and Jennings 1998), assigned case number 3012, and commentary solicited (see Smith 1999). Upon review the ICZN published Opinion 1961, voting 19-2 in favor of the petition to conserve prevailing usage (ICZN 2000): Under the plenary power all previous fixations of type specimens for the nominal species Coluber infernalis Blainville, 1835 are hereby set aside and the male specimen catalog no. 39197 in the California Academy of Sciences, San Francisco, is designated as the neotype. Though important, the details here can obscure the larger picture. Let’s step back and take a broader view. In brief, here’s what happened in case 3012. Two distinct taxa were identified and named, following the rules of the nomenclatural code specified in the ICZN. This includes specifying type specimens that act as the name-bearers for these taxa. The taxa simply are whatever taxa those type specimens belong to (here that would be sub-species). This sets up a central research problem for taxonomists: discovering what is included in the taxonomic boundaries of a given taxon. Systematic monographs and other 12

publications present hypotheses about those boundaries. Make no mistake, publications defining species names are not simply lists or mere descriptions of taxa. They are scientific (taxonomic) hypotheses of theoretical objects. Embedded in these hypotheses are all sorts of theoretical and conceptual commitments, e.g., how to disambiguate belongs to; what species concept is most appropriate and relevant, and how to apply it to a particular taxon; how theories, concepts, and empirical results from other fields of biology inform us of those taxonomic boundaries; and, finally, how taxonomic hypotheses are informative of and integrated with other fields of biology. As will be seen, the last of these is centrally important. The species names in case 3012 were defined legally and correctly. Researchers discovered, though, that application of the name generated a misidentification. Usage of the name referred to a species to which the type did not belong. Formally, this is to misapply the name: “To apply, deliberately or otherwise, a name in a sense which is not correct under the provisions of the Code (e.g., in a manner not in accord with the name-bearing type” (ICZN 1999, glossary). The example in this definition anchors the name with the type specimen; the type specimen is taken to provide “the objective standard of reference for the application of the name it bears” [Art. 61]. By default, when this is discovered there is a re-assignment of names, with application tracking the type specimens. However, the modal force of default is far more limited than, and should not be confused with, that of de dicto necessity. Indeed, that an option is a default implies that other possibilities remain, but only when actively triggered. It is meaningful that anchoring the name with the type specimen is presented as an example, rather than definitional of misapplying a name. This broader reading is supported in the ICZN’s definition of how researchers may misidentify specimens, i.e., “. . . mistakenly attribute a specimen to a particular taxon” (ICZN 1999, glossary). This can hold for any specimen, type included. Discovering and resolving a misidentification requires identifying which specimens have been misidentified. In some cases misidentification may be attributed to the type specimen, triggering (by active petition against the default) the designation of a neotype to serve as the name-bearer of that species. This is just what happened in case 3012. Misidentification is not the only reason type specimens may be suppressed and neotypes designated. For example, a type may have deteriorated to the point that utility is threatened, e.g., the pending case regarding Allosaurus, Marsh 1877 (Paul and Carpenter 2010). Type specimens are physical artifacts after all, and in the case of a well-studied taxon this can undermine one of the central aims of taxonomy. This constitutes another means by which a type specimen fails to belong of necessity to the species it designates. In general, petitions to the ICZN requesting designation of a neotype are not uncommon. At the time of writing there are twelve such cases pending, results of which will be published in the Bulletin of Zoological Nomenclature.

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Objections may be raised against the claim that de dicto necessity fails due to cases of misidentification. For example, how can misidentification occur well after a species is named? Surely that a type specimen must be designated in order to name a species indicates that there is a temporal priority to that type’s status as name-bearer and objective standard of application of that name. Of course, it is just this line of reasoning that justifies the default option in most cases. Yet that this is merely the default is relevant. To misidentify is to “mistakenly attribute a specimen to a particular taxon.” That a specimen was preserved and identified prior to careful study of a particular taxon does not mitigate that the type specimen is wrongly hypothesized to belong to that taxon. In the default case, the name and species identity sticks with the type. Where usage or stability of that name would be sufficiently disrupted, the location of misidentification is placed on the type specimen. It is re-assigned to a new species. Contrast that with the default case, where the species identity of the type specimen does not change (though the rest of the taxon is re-assigned). The upshot is that the identity conditions of type specimens and a designated species can come apart; both are contingent, and in either case de dicto necessity fails. That the temporal priority of designating a type specimen is irrelevant may also be drawn out by considering the contingency clause. Consider how a type specimen is selected. It need not be typical of the species, or possess familiar diagnostic characters (though that may be helpful in construction of taxonomic hypotheses). Suppose that upon discovery of a new species, multiple specimens were collected. It is contingent which of those is selected as the type. If the selected specimen were later discovered to belong to a different taxon than the other specimens, the type specimen was misidentified as belonging to the same taxon. How that misidentification might be resolved will depend on which Article of the ICZN is invoked and accepted. The default, again, will be that the name and taxonomic identity travel with the type; however, as in case 3012 described here, if Article 75.6 is successfully invoked than a neotype will be designated, and the type specimen assigned to a new species. Again, de dicto necessity fails to hold. Another objection may be that de dicto necessity still holds, but only under certain specified conditions, i.e., this is a case of ceteris peribus de dicto necessity. I am not convinced this is much of a necessity at all, and it would certainly entail only very weak modal force. Let’s leave this aside, and allow, for now, that it satisfies relevant claims of necessity. Furthermore, ceteris peribus conditions very rarely fail (given the number of named species), so perhaps we ought not pay it much heed. I think this would be a mistake. Firstly, that exceptions to de dicto necessity are built into the codes suggest it is not merely a failure of ceteris peribus conditions, but reflects a genuine complexity of taxonomic theory and conceptual structure of nomenclatural reference. Furthermore, the exceptions taken to justify the conservation of usage by designation of a neotype are illuminating. Taxonomy is a science that must be integrated with other fields 14

of biology. This is no mere practical matter, as proponents of consilience will surely agree. In case 3012, the deep integration with conservation biology provided strong support for the claim that a name change would threaten prevailing usage and stability. Conflict with other fields of biology is not uncommon, and taxonomists take these conflicts into consideration as mutual tests of theoretical commitments and hypotheses. Recall that taxon names are taxonomic hypotheses, hypotheses of biological objects and their parts, and characteristics of those parts. If these hypotheses conflict with practical, methodological, conceptual or theoretical concerns of the users of taxonomy, this is not merely a failure of ceteris paribus conditions, but may constitute genuine tests of the hypothesis. Locating the source of this conflict is a difficult scientific problem. In some cases taxonomy helps identify where other fields’ hypotheses are in need of revision;14 other times they may provide evidence for taxonomic revision, among which can be re-assignment of a type specimen to a new species.

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Conclusion

Taxonomy serves as a good testing ground for philosophical accounts of reference. Taxonomic names are proper names, designating individual taxa. The rules of biological nomenclature are transparent and explicit, and acts of naming public. Philosophical theories of naming and reference ought to apply. Philosophers may be tempted to dismiss cases like that of T.s.infernalis as mere exceptions to the rules. Yet this would be a mistake. Petitions of this sort are not unusual in taxonomy; to the contrary, provisions are specified for how to assess problematic cases such as these. Permitting re-designation of type specimens appears, at first glance, to present a serious challenge to philosophical accounts of proper names, or perhaps their applicability to biological taxonomy. Either would be worrisome, and demand revisions.15 I reconsidered Levine’s contingency problem and LaPorte’s solution in light of the case of the San Francisco Garter Snake. This introduced taxonomic practices and traditions not considered by Levine or LaPorte, yet ought to be accounted for in our philosophical treatment of proper names. Carefully working through this case illuminates theories of reference and biological nomenclature. Furthermore, I demonstrated and defended how the individuality thesis makes good sense of biological practice and tracks biologists’ theoretical and philosophical commitments. De dicto necessity only holds under idealized conditions— conditions that we know fail to hold. 14

Famously, Darwin drew upon just this sort of conflict to develop his theory of natural selection (Darwin 1859). 15 These are distinct concerns from those raised by a phylogenetic nomenclature (see Ereshefsky 2001), and would persist in such systems.

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So the contingency problem has been resolved, namely because it fails to get off the ground. Type specimens do not belong of necessity to the species they designate. Yet this solution comes at a cost: it suggests that rigid designation and the causal theory of reference are perhaps more fragile than supposed. Ironically, this ultimately supports Levine’s larger argument: criticizing theories of reference relying on ostensive definitions and rigid designators. I suspect that the complications described here have a limited (though important) scope, and, ultimately, can be accounted for in those theories. Regardless, misidentification of type specimens is something that ought to be accounted for in our theories of reference and naming, and not merely brushed aside. So though the relation between a type specimen and the species it identifies is a tight one, it is not a relation of necessity. Our analyses of how names designate individuals must account for this, i.e., they must tell us how to misidentify a type specimen.

References Barry, S. J. and Jennings, M. R. (1998). Coluber infernalis Blainville, 1835 and Eutaenia sirtalis tetrataenia Cope in Yarrow, 1875 (currently Thamnophis sirtalis infernalis and T. s. tetrataenia; reptilia, squamata): proposed conservation of the subspecific names by the designation of a neotype for T. s. infernalis. Bulletin of Zoological Nomenclature, 55(4):224–228. Barry, S. J., Jennings, M. R., and Smith, H. M. (1996). Current subspecific names for western Thamnophis sirtalis. Herpetological Review, 27(4):172–173. Boundy, J. and Rossman, D. A. (1995). Allocation and status of the garter snake names Coluber infernalis Blainville, Eutaenia sirtalis tetrataenia Cope and Eutaenia imperialis Coues and Yarrow. Copeia, 1995(1):236–240. Brasier, C. (1992). A champion thallus. Nature, 356(6368):382–383. Cope, E.D. in Yarrow, H.C. (1875). Report upon the collections of batrachians and reptiles made in portions of Nevada, Utah, California, Colorado, New Mexico, and Arizona, during the years 1871, 1872, 1873 and 1874. Pp 509-584. In Engineer Dept., U.S.A., editor, Report upon geographical and geological explorations and surveys west of the one hundredth meridian, volume 5 (Zoology), part 4, page 546. Darwin, C. (1964 [1859]). On the Origin of Species. Harvard University Press, Cambridge, MA, 1st (facsimile) edition. de Blainville, H. (1835). Description de quelques esp`eces de reptiles de californie: pr´ec´ed´ee de l’analyse d’un syst`eme g´en´eral d’erp´etologie et d’amphibiologie. Nouvelles Annales du Mus´eum d’Histoire Naturelle, 3(4):291.

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Dupr´e, J. (2010). The polygenomic organism. The Sociological Review, 58:19–31. Ereshefsky, M. (2001). The Poverty of the Linnaean Hierarchy. Cambridge University Press, Cambridge. Ereshefsky, M. (2010). What’s wrong with the new biological essentialism. Philosophy of Science, 77(5):674–685. Ghiselin, M. T. (1966). On psychologism in the logic of taxonomic controversies. Systematic Zoology, 15(3):207–215. Ghiselin, M. T. (1974). A radical solution to the species problem. Systematic Zoology, 23(4):536–544. Ghiselin, M. T. (1995). Ostensive definitions of the names of species and clades. Biology and Philosophy, 10:219–222. Ghiselin, M. T. (1997). Metaphysics and the origin of species. SUNY series in philosophy and biology. SUNY Press. Haber, M. H. (forthcoming). Colonies are individuals: Revisiting the superorganism revival. In Bouchard, F. and Huneman, P., editors, From Groups to Individuals: Perspectives on Biological Associations and Emerging Individuality, The Vienna Series in Theoretical Biology. MIT Press. Hull, D. L. (1976). Are species really individuals? Systematic Zoology, 25(2):174–191. Hull, D. L. (1978). A matter of individuality. Philosophy of Science, 45(3):335–360. International Commission on Zoological Nomenclature (1999). International Code of Zoological Nomenclature. The International Trust for Zoological Nomenclature 1999, 4th edition. International Commission on Zoological Nomenclature (2000). Opinion 1961: Coluber infernalis Blainville, 1835 and Eutaenia sirtalis tetrataenia Cope in Yarrow, 1875 (currently Thamnophis sirtalis infernalis and T. s. tetrataenia; reptilia, serpentes): subspecific names conserved by the designation of a neotype for T. s. infernalis. Bulletin of Zoological Nomenclature, 57(3):191–192. Jubien, M. (2009). Possibility. Oxford University Press, Oxford. Kitcher, P. (1984). Species. Philosophy of Science, 51(2):308–333. Kitcher, P. (1987). Ghostly whispers: Mayr, Ghiselin, and the “philosophers” on the ontological status of species. Biology and Philosophy, 2:184–192. Kripke, S. A. (1980). Naming and Necessity. Harvard University Press, 2nd edition.

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LaPorte, J. (2003). Does a type specimen necessarily or contingently belong to its species? Biology and Philosophy, 18:583–588. Levine, A. (2001). Individualism, type specimens, and the scrutability of species membership. Biology and Philosophy, 16(3):325–338. Paul, G. and Carpenter, K. (2010). Allosaurus Marsh, 1877 (Dinosauria, Theropoda): proposed conservation of usage by designation of a neotype for its type species Allosaurus fragilis Marsh, 1877. Bulletin of Zoological Nomenclature, 67(1):53–56. Putnam, H. (1975). The meaning of ‘meaning’. In Gunderson, K., editor, Language, Mind and Knowledge, Minnesota Studies in the Philosophy of Science VII, pages 131–193. University of Minnesota Press, Minneapolis, MN. Smith, H. M. (1999). Comment on the proposed conservation of Coluber infernalis Blainville, 1835 and Eutaenia sirtalis tetrataenia Cope in Yarrow, 1875 (currently Thamnophis sirtalis infernalis and T. s. tetrataenia; Reptilia, Squamata): proposed conservation of the subspecific names by the designation of a neotype for T. s. infernalis. Bulletin of Zoological Nomenclature, 56(1):71–72. Smith, M. L., Bruhn, J. N., and Anderson, J. B. (1992). The fungus armillaria bulbosa is among the largest and oldest living organisms. Nature, 356(6368):428–431. Sober, E. (1980). Evolution, population thinking, and essentialism. Philosophy of Science, 47(3):350–383. Sober, E. (1984). Sets, species, and evolution: Comments on Philip Kitcher’s “species”. Philosophy of Science, 51(2):334–341. Varzi, A. C. (2006). A note on the transitivity of parthood. Applied Ontology, 1(2):141. Winston, J. E. (1999). Describing Species: Practical Taxonomic Procedure for Biologists. Columbia University Press, New York. Yu, N., Kruskall, M. S., Yunis, J. J., Knoll, J. H., Uhl, L., Alosco, S., Ohashi, M., Clavijo, O., Husain, Z., Yunis, E. J., Yunis, J. J., and Yunis, E. J. (2002). Disputed maternity leading to identification of tetragametic chimerism. New England Journal of Medicine, 346(20):1545–1552.

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