David Magnus

Biologists often define evolution as a change in allele frequencies. Consideration of the evolution of the pocket mouse will show that it is possible to have evolution without any change in the allele frequencies in a population (through change in the genotype frequencies). The implications of this for genic selectionism are then discussed. Sober and Lewontin (1982) have constructed an example to demonstrate the blindness of genic selectionism in certain cases. Sterelny and Kitcher (1988) offer a defense against these arguments which assumes a conventionalist approach to populations. The example considered here will be shown to offer a more plausible and far-reaching argument against the view that alleles can always be seen as the units of selection.

Approaching science by considering the epistemological virtues which scientists see as constitutive of good science, and the way these virtues trade-off against one another, makes it possible to capture action that may be lost by approaches which focus on either the theoretical or institutional level. Following Wimsatt (1984) I use the notion of heuristics and biases to help explore a case study from the history of biology. Early in the 20th century, mutation theorists and natural historians fought over the role that isolation plays in evolution. This debate was principally about whether replication was the central scientific virtue (and hence the ultimate goal of science to replace non-experimental evidence with experimental evidence) or whether consilience of inductions was the central virtue (and hence, as many kinds of evidence as possible should be pursued).