International Society for History, Philosophy, and Social Studies of Biology

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THURSDAY, JULY 9  /  09:00 - 10:30  /  DS-R515
Individual papers
Interactors, Immunology and Cancer: Levels of Selection Questions?

Immunological individuation and units of selection

Daniel Molter (University of Utah, United States)

In this essay I challenge two metaphysical consequences that Thomas Pradeu (2012) claims follow from conceiving of organisms as being physiologically individuated by their immune systems. The first consequence is that organisms achieve the highest degree of biological individuality. The second consequence is that such organisms are heterogeneous. I argue that Pradeu’s view of the organism as both heterogeneous and endowed with the highest degree of biological individuality is conceptually flawed, as both claims about organisms generate paradoxes in some biological contexts. In light of these paradoxes I argue that we should look to evolution rather than to physiology to provide a theoretical foundation for biological individuality at the level of the organism. Despite conceptual flaws in his formulation of the organism, I argue that immunity, understood in terms of Pradeu’s continuity theory, does in fact provide a physiological criterion of biological individuation, one unique in its ability to weave heterogeneous strands of the genealogical nexus into a single discrete unit of selection. However, I argue that these heterogeneous units of selection should not usurp the name ‘organism’, as much of biological theory, especially population genetics, requires a homogeneous single-species concept of organism. I argue that we should retain the view that an organism is part of a single species lineage and use the term “holobiont” (Mindell 1992, cf. Booth 2014a) to refer to immunologically-integrated multi-lineage units of selection.

Pluralism and the levels of selection in cancer: Toward a genomic model

Joseph Wu (Duke University, United States)

The recognition that cancer is an evolutionary process has yielded many insights for understanding the dynamic nature of the disease. But an evolutionary perspective bequeaths a philosophical problem that has largely been ignored by cancer researchers, namely, the levels of selection. In this paper I explain how cancer is an evolutionary process and why the levels of selection issue is central to understanding the origin and existence of cancer. I then clarify the difference between pluralist and monist interpretations of the levels of selection disputes, a philosophical distinction that many scientists are unaware of. Applying James Woodward’s theory of causation, I argue for pluralism and show how a genomic model of cancer parses the causes differently to provide an equally accurate representation of carcinogenesis. I conclude by suggesting pragmatic advantages of a genomic model of cancer in biomedical research.

The return of the interactor

Austin Booth (Dalhousie University, Canada)

The evolutionary importance of consortia of taxonomically divergent lineages has been the subject of much discussion in recent philosophy of biology. An increasingly popular unifying approach is a Hull-style perspective in which the interactor concept is revised and adapted to account for the evolutionary role of multilineage consortia. I offer an analysis of this new kind of interactor-based approach to understanding the evolution of multilineage entities. I argue that an interactor-based approach needn’t be coupled with a traditional replicator concept. I then make note of some evolutionarily relevant axes along which interactors can (and do) vary in nature. At stake is whether or not multilineage interactors should be understood as units of selection, to what extent they are genuine reproducers or merely systems that recur in each generation, and what kinds of interactions between their parts bind them into genuine biological individuals.