Natural kinds in biology? Genes and modules as a case study (extended abstract for: Séminaire de Philosophie de la Biologie de l'IHPST, April 5, 2007) Thomas A.C. Reydon Center for Philosophy and Ethics of Science (ZEWW) Leibniz University Hannover Im Moore 21, D-30167 Hannover, Germany e-mail:
[email protected] web: http://unics.rrzn.uni-hannover.de/zeww Background Philosophers have long treated the topic of natural kinds as essentially a question of ontology. Starting from the assumption that the things in the world by their natures come in different kinds, the scientists’ traditional task was to tell us which natural kinds there are in the world and to uncover their real essences. Building on the scientists’ results, the philosophers’ challenge was to come up with an overarching account of the precise nature of the natural kinds discovered by science and of the ways in which these feature in everyday language, scientific reasoning and investigative practices. So far, however, this way of approaching the issue has not resulted in any generally accepted account of what exactly natural kinds are, which (if any) natural kinds there are in the world and whether natural kinds play any important role at all in science. An alternative approach to the topic of natural kinds starts from studying how natural kinds feature in scientific practice. This approach is suggested by the fact that the notion of natural kinds has long (at least since William Whewell, John Stuart Mill and John Venn formally coined the terms ‘kind’ and ‘natural kind’ as technical terms in philosophy) served philosophers as a tool for studying how scientific inferences (as well as inferences in everyday language) are supported. From this perspective, a more promising path to take is to first address the various epistemological issues that occur regarding natural kinds in the various scientific practices in which they are used by scientists, with ontological issues coming second in line. On taking this approach, elaborating a philosophical account of natural kinds begins by examining which roles natural kinds play in actual science, i.e., by looking at how classifications of the subject matter of various scientific disciplines into natural kinds are actually being used in these disciplines’ practices of investigation and knowledge production, in their ways of reasoning and in the explanations that they provide. Once we know what these epistemic roles are, we can go on to investigate what the ontology of natural kinds must be to enable them to perform these roles. Genes and modules I shall take the abovementioned approach to a case study from the domains of genetics and developmental biology. The gene category and particular gene kinds have long been considered as candidate natural kinds for these domains of work. In addition, several authors have suggested that developmental modules should be conceptualized as constituting natural kinds. This case study examines (1) in which ways the gene category, particular gene kinds, the developmental module category and particular kinds of developmental modules perform typical ‘natural kind roles’ in the investigative practices of these disciplines and (2) which
ontology of natural kinds would fit these roles. I shall argue that a non-essentialist notion of natural kinds is required to make sense of how biologists use these candidate kinds and that such a notion of natural kinds can be a useful tool for realizing philosophy of science’s central goal of understanding how actual science works. The ideas and results that will be presented are work in progress. They are part of a 3year project with the title “How do life scientists generalize? Natural kinds as the grounds for explanatory generalizations in the life sciences”, that is currently under way at the ZEWW in Hannover, funded by a fellowship from the German Research Council (DFG).
