This paper explores whether natural selection, a putative evolutionary mechanism, and a main one at that, can be characterized on either of the two dominant conceptions of mechanism, due to Glennan and the team of Machamer, Darden, and Craver, that constitute the "new mechanistic philosophy." The results of the analysis are that neither of the dominant conceptions of mechanism adequately captures natural selection. Nevertheless, the new mechanistic philosophy possesses the resources for an understanding of natural selection under the rubric.

This paper considers recent heated debates led by Jerry A. Coyne and Michael J. Wade on issues stemming from the 1929-1962 R. A. Fisher−Sewall Wright controversy in population genetics. William B. Provine once remarked that the Fisher−Wright controversy is central, fundamental, and very influential. Indeed, it is also persistent. The argumentative structure of the recent (1997-2000) debates is analyzed with the aim of eliminating a logical conflict in them, viz., that the two "sides" in the debates have different aims and that, as such, they are talking past each other. Given a philosophical analysis of the argumentative structure of the debates, suggestions supportive of Wade's work on the debate are made that are aimed, modestly, at putting the persistent Fisher−Wright controversy on the course to resolution.

) have endorsed views about random drift that, we will argue, rest on an implicit assumption that the meaning of concepts such as drift can be understood through an examination of the mathematical models in which drift appears. They also seem to implicitly assume that ontological questions about the causality (or lack thereof) of terms appearing in the models can be gleaned from the models alone. We will question these general assumptions by showing how the same equation -the simple (p + q) 2 = p 2 + 2pq + q 2 -can be given radically different interpretations, one of which is a physical, causal process and one of which is not. This shows that mathematical models on their own yield neither interpretations nor ontological conclusions. Instead, we argue that these issues can only be resolved by considering the phenomena that the models were originally designed to represent and the phenomena to which the models are currently applied. When one does take those factors into account, starting with the motivation for Sewall Wright's and R.A. Fisher's early drift models and ending with contemporary applications, a very different picture of the concept of drift emerges. On this view, drift is a term for a set of physical processes, namely, indiscriminate sampling processes (Beatty 1984;Hodge 1987;Millstein 2002Millstein , 2005.

Sewall Wright's adaptive landscape is the most influential heuristic in evolutionary biology. Wright's biographer, Provine, criticized Wright's adaptive landscape, claiming that its heuristic value is dubious because of deep flaws. Ruse has defended Wright against Provine. Ruse claims Provine has not shown Wright's use of the landscape is flawed, and that, even if it were, it is heuristically valuable. I argue that both Provine's and Ruse's analyses of the adaptive landscape are defective and suggest a more adequate understanding of it.

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