Online research in philosophy

In “Two Ways of Thinking About Fitness and Natural Selection” (Matthen and Ariew [2002]; henceforth “Two Ways”), we asked how one should think of the relationship between the various factors invoked to explain evolutionary change – selection, drift, genetic constraints, and so on. We suggested that these factors are not related to one another as “forces” are in classical mechanics. We think it incoherent, for instance, to think of natural selection and drift as separate and opposed “forces” in evolutionary change (...) – that it makes sense to say, for instance, that selection contributed 80% to the actual evolutionary history of the human eye, and drift only 20%. We proposed instead a statistical view of the Theory of Evolution, a view in which fitness is not a cause of evolution, but rather a measure of growth. We also argued for a “hierarchical realization model” for thinking about the relationship between evolutionary factors such as those mentioned above, and suggested that in a “fully specified model”, as we call it below, there is no distinction between natural selection and evolution. (shrink)

ÒThe concept of fitness is,Ó Philip Kitcher says, Òimportant both to informal presentations of evolutionary theory and to the mathematical formulations of [population genetics].Ó1 He is absolutely right. The difficulty is to harmonize these very different ways of understanding its role. In this paper, we examine how natural selection relates to the other explanatory factors invoked by evolutionary theory. We argue that the Òinformal presentationsÓ to which Kitcher alludes give an incoherent account of the relation. A more appropriate model is (...) drawn from the statistical conceptual framework of population genetics. We argue that this model demands a far-reaching revision of some widely accepted notions of causal relations in evolution. (shrink)

The theory of natural selection is a rich systematization of biological knowledge without a first principle. When formulations of a proposed principle of natural selection are examined carefully, each is seen to be exhaustively analyzable into a proposition about sources of fitness and a proposition about consequences of fitness. But whenever the fitness of an organic variety is well defined in a given biological situation, its sources are local contingencies together with the background of laws from disciplines other than the (...) theory of natural selection; and the consequences of fitness for the long range fate of organic varieties are essentially applications of probability theory. Hence there is no role and no need for a principle of the theory of natural selection, and any generalities that may hold in that theory are derivative rather than fundamental. (shrink)