Typology Reconfigured: From the Metaphysics of Essentialism to the Epistemology of Representation

Abstract

The goal of this paper is to encourage a reconfiguration of the discussion about typology in biology away from the metaphysics of essentialism and toward the epistemology of classifying natural phenomena for the purposes of empirical inquiry. First, I briefly review arguments concerning 'typological thinking', essentialism, species, and natural kinds, highlighting their predominantly metaphysical nature. Second, I use a distinction between the aims, strategies, and tactics of science to suggest how a shift from metaphysics to epistemology might be accomplished. Typological thinking can be understood as a scientific tactic that involves representing natural phenomena using idealizations and approximations, which facilitates explanation, investigation, and theorizing via abstraction and generalization. Third, a variety of typologies from different areas of biology are introduced to emphasize the diversity of this representational reasoning. One particular example is used to examine how there can be epistemological conflict between typology and evolutionary analysis. This demonstrates that alternative strategies of typological thinking arise due to the divergent explanatory goals of researchers working in different disciplines with disparate methodologies. I conclude with several research questions that emerge from an epistemological reconfiguration of typology.

Explanation in Biology: Reduction, Pluralism, and Explanatory Aims

“…For instance, construals of biological species as natural kinds with essences focus on some features that are shared among the members of a species (essential properties), thereby inevitably ignoring within-species variation, which must not be neglected on any account of why and how species evolve (Sober 1980 For example, descriptions in developmental biology break the development of a model organism species into normal stages (e.g., molt-to-molt intervals in insects). While this is useful for explaining development, the distinct explanatory aim of accounting for the evolution of development may require a different representational framework because developmental biology's normal stages obscure natural variation in development, phenotypic plasticity, and the way in which developmental stages are created and transformed in evolution (Love 2009(Love , 2010. Explaining the development of a species and explaining the evolution of this species's development are two different explanatory aims about the same empirical object, and different representations of this object are needed to meet the respective aims.…”

Evo-devo: a science of dispositions

“…Because attempting to define any particular module with a specific set of genetic elements has proven an unfruitful endeavour, the focus has largely shifted to conceptualising these modules as centres of generative, rather than genetic specificity (Rieppel 2005;Love 2009;Brigdandt 2009). For while it"s undeniable that tracing the particularities of repeated genetic architectural themes throughout evolutionary time has led to incredibly important insights in establishing molecular-based phylogenetic lineages, the aforementioned phenomenon of degenerative robustness ensures the existence of multiple variations in the regulatory architecture responsible for the production of a single, specific morphological structure.…”

The ontology of organisms: Mechanistic modules or patterned processes?

“…The now classic paragon of this is Owen"s (1848) own -that of the tetrapod limb which, although performing a variety of distinct functions in its multiple instances throughout evolutionary history, is readily identifiable in innumerable species despite its specific generative competency being developmentally anchored in a wide variety of diverse underlying GRNs throughout those instances (Zuniga 2015). 5 Due to the co-variational disconnect between the mechanistic composition and the morphological product of these modules, it has been increasingly conceptually advantageous to functionally individuate them with respect to their generatively specific end-states -that is, according to their generative capacities in establishing structurally specific morphospaces, the varied permutations of which represent species-specific instances of their respective homologues (Rieppel 2005;Brigandt 2007;Love 2009;Wagner 2014). Individuating the modules which are causally responsible for homologues functionally allows them to feature in higher-order explanations of developmental phenomena, ones which operate at a higher "causality horizon" (Salazar-Ciudad & Jernvall 2013), or at explanatory levels "above" the workings 3 It may even be the case, as has recently been argued, that the generative robustness inherent in developmental systems is in fact a necessary requirement for their ability to evolve.…”