Anya Plutynski

Comprised of essays by top scholars in the field, this volume offers concise overviews of philosophical issues raised by biology. Brings together a team of eminent scholars to explore the philosophical issues raised by biology Addresses traditional and emerging topics, spanning molecular biology and genetics, evolution, developmental biology, immunology, ecology, mind and behaviour, neuroscience, and experimentation Begins with a thorough introduction to the field Goes beyond previous treatments that focused only on evolution to give equal attention to other areas, such as molecular and developmental biology Represents both an authoritative guide to philosophy of biology, and an accessible reference work for anyone seeking to learn about this rapidly-changing field

The recent literature in philosophy of biology has drawn attention to the different sorts of explanations proffered in the biological sciences—we have molecular, biomedical, and evolutionary explanations. Do these explanations all have a common structure or relation that they seek to capture? This paper will answer in the negative. I defend a pluralistic and pragmatic approach to explanation. Using examples from classical population genetics, I argue that formal demonstrations, and even strictly “mathematical truths,” may serve as explanatory in different historical contexts.

In 1968, Motoo Kimura submitted a note to Nature entitled “Evolutionary Rate at the Molecular Level,” in which he proposed what has since become known as the neutral theory of molecular evolution. This is the view that the majority of evolutionary changes at the molecular level are caused by random drift of selectively neutral or nearly neutral alleles. Kimura was not proposing that random drift explains all evolutionary change. He does not challenge the view that natural selection explains adaptive evolution, or, that the vertebrate eye or the tetrapod limb are products of natural selection. Rather, his objection is to “panselectionism’s intrusion into the realm of molecular evolutionary studies”. According to Kimura, most changes at the molecular level from one generation to the next do not affect the fitness of organisms possessing them. King and Jukes (1969) published an article defending the same view in Science, with the radical title, “Non- Darwinian Evolution,” at which point, “the fat was in the fire” (Crow, 1985b). The neutral theory was one of the most controversial theories in biology in the late twentieth century. This chapter will review the debate over the netural theory subsequent to Kimura.