Golden spikes, scientific types, and the ma(r)king of deep time.

Chronostratigraphy is the subfield of geology that studies the relative age of rock strata and that aims at producing a hierarchical classification of (global) divisions of the historical time-rock record. The 'golden spike' or 'GSSP' approach is the cornerstone of contemporary chronostratigraphic methodology. It is also perplexing. Chronostratigraphers define each global time-rock boundary extremely locally, often by driving a gold-colored pin into an exposed rock section at a particular level. Moreover, they usually avoid rock sections that show any meaningful sign of paleontological disruption or geological discontinuity: the less obvious the boundary, the better. It has been argued that we can make sense of this practice of marking boundaries by comparing the status and function of golden spikes to that of other concrete, particular reference standards from other sciences: holotypes from biological taxonomy and measurement prototypes from the metrology of weight and measures. Alisa Bokulich (2020b) has argued that these 'scientific types' are in an important sense one of a kind: they have a common status and function. I will argue that this picture of high-level conceptual unity is mistaken and fails to consider the diversity of aims and purposes of standardization and classification across the sciences. I develop an alternative, disunified account of scientific types that shows how differences in ontological attitudes and epistemic aims inform scientists' choices between different kinds of scientific types. This perspective on scientific types helps to make sense of an intriguing mid-twentieth-century debate among chronostratigraphers about the very nature of their enterprise. Should chronostratigraphers conventionally make boundaries by designating golden spikes, or should they attempt to mark pre-existing 'natural' boundaries with the help of a different kind of scientific type?

Taxon names and varieties of reference.

Linnaean-style, rank-based codes of taxonomic nomenclature provide stability to the relation between taxon names and their referents through the device of nomenclatural types. The practice of using types to tether names to taxa is uncontroversial and well-understood. But the nature of the relation between types, names, and taxa continues to be a topic of philosophical debate. A particularly contested issue is whether it is necessary for taxa that have a type specimen to contain their type specimen. Jerzy Brzozowski has recently offered a novel account of taxon names that, he claims, shows that the relation between a type specimen and the (sub)species it belongs to is contingent (Brzozowski in Hist Philos Life Sci 42(3):1-25, 2020). I argue that this is mistaken. While Brzozowski's contribution helps to advance the debate by bringing concepts from the philosophy of reference to bear on taxonomic naming practices, his new account of taxon names fails to support his central argument. Indeed, I show that the philosophical concepts he introduces into the debate cement the view that it is necessary for a (sub)species with a type specimen to contain it.

Of elephants and errors: naming and identity in Linnaean taxonomy.

What is it to make an error in the identification of a named taxonomic group? In this article we argue that the conditions for being in error about the identity of taxonomic groups through their names have a history, and that the possibility of committing such errors is contingent on the regime of institutions and conventions governing taxonomy and nomenclature at any given point in time. More specifically, we claim that taxonomists today can be in error about the identity of taxonomic groups in a way that Carl Linnaeus (1707-1778), who is routinely cited as the "founder" of modern taxonomy and nomenclature, simply could not be. Starting from a remarkable recent study into Linnaeus's naming of Elephas maximus that led to the (putative) discovery of a (putative) nomenclatural error by him, we reconsider what it could mean to discover that Linnaeus misidentified a biological taxon in applying his taxon names. Through a further case study in Linnaean botany, we show that his practices of (re)applying names in taxonomic revisions reveal a take on determining "which taxon is which" that is strikingly different from that of contemporary taxonomists. Linnaeus, we argue, adopted a practice-based, hands-on concept of taxa as "nominal spaces" that could continue to represent the same taxon even if all its former members had been reallocated to other taxa.

Coordinating dissent as an alternative to consensus classification: insights from systematics for bio-ontologies.

The collection and classification of data into meaningful categories is a key step in the process of knowledge making. In the life sciences, the design of data discovery and integration tools has relied on the premise that a formal classificatory system for expressing a body of data should be grounded in consensus definitions for classifications. On this approach, exemplified by the realist program of the Open Biomedical Ontologies Foundry, progress is maximized by grounding the representation and aggregation of data on settled knowledge. We argue that historical practices in systematic biology provide an important and overlooked alternative approach to classifying and disseminating data, based on a principle of coordinative rather than definitional consensus. Systematists have developed a robust system for referring to taxonomic entities that can deliver high quality data discovery and integration without invoking consensus about reality or "settled" science.

Typological thinking: Then and now.

A popular narrative about the history of modern biology has it that Ernst Mayr introduced the distinction between "typological thinking" and "population thinking" to mark a contrast between a metaphysically problematic and a promising foundation for (evolutionary) biology, respectively. This narrative sometimes continues with the observation that, since the late-20th century, typological concepts have been making a comeback in biology, primarily in the context of evolutionary developmental biology. It is hard to square this narrative with the historical and philosophical literature on the typology/population distinction from the last decade or so. The conclusion that emerges from this literature is that the very distinction between typological thinking and population thinking is a piece of mere rhetoric that was concocted and rehearsed for purely strategic, programmatic reasons. If this is right, it becomes hard to make sense of recent criticisms (and sometimes: espousals) of the purportedly typological underpinnings of certain contemporary research programs. In this article, I offer a way out of this apparent conflict. I show that we can make historical and philosophical sense of the continued accusations of typological thinking by looking beyond Mayr, to his contemporary and colleague George Gaylord Simpson. I show that before Mayr discussed the typology/population distinction as an issue in scientific metaphysics, Simpson introduced it to mark several contrasts in methodology and scientific practice. I argue that Simpson's insightful discussion offers useful resources for classifying and assessing contemporary attributions of typological thinking.

"A temporary oversimplification": Mayr, Simpson, Dobzhansky, and the origins of the typology/population dichotomy (part 2 of 2).

The dichotomy between 'typological thinking' and 'population thinking' features in a range of debates in contemporary and historical biology. The origins of this dichotomy are often traced to Ernst Mayr, who is said to have coined it in the 1950s as a rhetorical device that could be used to shield the Modern Synthesis from attacks by the opponents of population biology. In this two-part essay, I argue that the origins of the typology/population dichotomy are considerably more complicated and more interesting than is commonly thought. In the first part, I argued that Mayr's dichotomy was based on two distinct type/population contrasts that had been articulated much earlier by George Gaylord Simpson and Theodosius Dobzhansky. Their distinctions made eminent sense in their own, isolated contexts. In this second part, I will show how Mayr conflated these type/population distinctions and blended in some of his own, unrelated concerns with 'types' of a rather different sort. Although Mayr told his early critics that he was merely making "a temporary oversimplification," he ended up burdening the history and philosophy of biology with a troubled dichotomy.

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

'Type' in biology is a polysemous term. In a landmark article, Paul Farber (Journal of the History of Biology 9(1): 93-119, 1976) argued that this deceptively plain term had acquired three different meanings in early nineteenth century natural history alone. 'Type' was used in relation to three distinct type concepts, each of them associated with a different set of practices. Important as Farber's analysis has been for the historiography of natural history, his account conceals an important dimension of early nineteenth century 'type talk.' Farber's taxonomy of type concepts passes over the fact that certain uses of 'type' began to take on a new meaning in this period. At the closing of the eighteenth century, terms like 'type specimen,' 'type species,' and 'type genus' were universally recognized as referring to typical, model members of their encompassing taxa. But in the course of the nineteenth century, the same terms were co-opted for a different purpose. As part of an effort to drive out nomenclatural synonymy - the confusing state of a taxon being known to different people by different names - these terms started to signify the fixed and potentially atypical name-bearing elements of taxa. A new type concept was born: the nomenclatural type. In this article, I retrace this perplexing nineteenth century shift in meaning of 'type.' I uncover the nomenclatural disorder that the new nomenclatural type concept dissolved, and expose the conceptual confusion it left in its tracks. What emerges is an account of how synonymy was suppressed through the coinage of a homonym.

"A temporary oversimplification": Mayr, Simpson, Dobzhansky, and the origins of the typology/population dichotomy (part 1 of 2).

The dichotomy between 'typological thinking' and 'population thinking' features in a range of debates in contemporary and historical biology. The origins of this dichotomy are often traced to Ernst Mayr, who is said to have coined it in the 1950s as a rhetorical device that could be used to shield the Modern Synthesis from attacks by the opponents of population biology. In this two-part essay I argue that the origins of the typology/population dichotomy are considerably more complicated and more interesting than is commonly thought. In this first part, I will argue that Mayr's dichotomy was based on two distinct type/population contrasts that had been articulated much earlier by George Gaylord Simpson and Theodosius Dobzhansky. Their distinctions made eminent sense in their own, isolated contexts. In the second part, I will show how Mayr conflated these type/population distinctions and blended in some of his own, unrelated concerns with 'types' of a rather different sort. Although Mayr told his early critics that he was merely making "a temporary oversimplification," he ended up burdening the history and philosophy of biology with a troubled dichotomy.