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


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Program

THURSDAY, JULY 9  /  09:00 - 10:30  /  DS-R510
Organized session / standard talks
Mechanisms of evolution
Organizer(s):

Eric Saidel (George Washington University, United States)

The New Mechanistic Philosophy has provided a new and exciting way to think about explanation in biology. The new mechanists suggest that discovery and explanation in biology proceeds by searching for and finding mechanisms. In expanding the insights of the new mechanists, philosophers have wondered about the scope of mechanistic explanation. In particular, can mechanistic explanations be extended to the phenomena of evolution? This session aims to explore this question. Lindley Darden (an author of one of the seminal New Mechanistic texts) will discuss the role of next generation sequencing of whole genomes in the study of mechanisms responsible for reproductive isolation; her talk will put study of adaptive speciation mechanisms into the context of a multilevel view of evolutionary mechanisms. Thus, she will be applying a new method of analysis to Darwin’s principle of divergence. Fermin Fulda engages with an existing debate about the conceptual foundations of evolutionary theory: should we conceive of evolution by natural selection as a causal phenomenon or as a statistical phenomenon? Fulda will argue that a mechanistic interpretation of natural selection is in fact compatible with a statistical interpretation of evolutionary theory. More specifically, a mechanistic interpretation of selection-for explanations is compatible with a statistical interpretation of selection-of explanations. Eric Saidel will address the active debate about whether evolution by natural selection can be considered a mechanism. He will argue that evolution by natural selection does fit at least one conception of mechanistic explanation, but that (contrary to the claims of at least one author of this conception) successful mechanistic explanations do not require reifying the mechanisms appealed to in those explanations. Jessica Pfeifer, who works on philosophy of evolutionary theory, will chair.


Speciation mechanisms, genomes, and reproductive isolation

Lindley Darden (University of Maryland, College Park, United States)

Next generation sequencing of whole genomes has revolutionized the study of mechanisms related to speciation. As in many areas of biology, the generation of "big data" currently outstrips the computational approaches to analyze it. Methods are needed to relate genome differences to ecologically significant factors and identify the mechanisms for explaining the genomic patterns of species divergence. Charles Darwin would likely be delighted to see this new method for analysis of his principle of divergence and current work on ecologically driven selection in adaptive speciation. This talk will put study of adaptive speciation mechanisms into the context of a multilevel view of evolutionary mechanisms, from genetic and chromosomal mechanisms yielding variation, to natural selection as the mechanism producing adaptations, to speciation mechanisms producing biological diversity.


Natural selection, mechanistic explanation and the statistical interpretation

Fermin Fulda (University of Toronto, Canada)

Two recent debates in the philosophy of biology concern the causal vs. statistical interpretation of evolutionary theory and whether natural selection is a mechanism. I suggest that we can gain some clarity about the conceptual and methodological foundations of evolutionary theory by asking about how these issues are related. One might think that if natural selection is a mechanism then evolutionary theory must be a causal theory. Conversely, one might think that if evolutionary theory is a statistical theory then natural selection cannot be a mechanism. The mechanistic interpretation of natural selection, it seems, is incompatible with the statistical interpretation of evolutionary theory. By using the selection-for/of distinction, I will argue that a mechanistic interpretation of natural selection is in fact compatible with a statistical interpretation of evolutionary theory. More specifically, I will argue that a mechanistic interpretation of selection-for explanations is compatible with a statistical interpretation of selection-of explanations. While the former corresponds to ecological studies of actual selective forces familiar from Darwin’s theory of evolution, the latter correspond to population-genetic studies of idealized statistical trends familiar from the Modern-Synthesis theory of evolution. Conceiving selection-for explanations mechanistically does not imply that natural selection itself is a mechanism, thus preventing unnecessary reification. It also allows us to secure the causal-mechanical basis of evolutionary theory while preserving the distinctive statistical content of population-genetic models.


Mechanistic explanation without mechanisms

Eric Saidel (George Washington University, United States)

Does the New Mechanistic approach to explanation in the biological sciences extend to evolution by natural selection? According to the dominant views of mechanistic explanation to give a mechanistic explanation of a phenomenon involves finding a mechanism that produces the phenomenon. Thus some philosophers (e.g., Skipper and Millstein (2005)) argue that even if we could make evolution by natural selection fit the required parameters demanded by the New Mechanistic philosophy, it would not be a mechanism; no single mechanism could account for the entirety of the phenomena. Others (e.g., Barros (2008)) argue that since the diverse phenomena of evolution by natural selection can be unified in an abstract mechanism schema, evolution can be thought of as a mechanism. This paper challenges the ontological shift from mechanistic explanation to mechanism. The right explanation of a phenomenon may be mechanistic even though the ontological interpretation of that explanation is not justified. There is no object that is the mechanism that produces evolution by natural selection. Nonetheless, evolution by natural selection can be fruitfully characterized as an organization of entities and activities. By so characterizing evolution by natural selection we gain explanatory purchase on the regularities that we observe in the many instances of evolution by natural selection.