 The point of departure for many philosophers criticizing heritability analysis is Lewontin’s (1974) paper on the analysis of variance. (It is worth noting that Lewontin’s paper is somewhat informal and should perhaps be best viewed as Lewontin’s attempt to pass on the received wisdom among population geneticists at the time to a wider audience. The formal arguments Lewontin alludes to are presented in a number of places including Layzer (1974) (and later Kempthorne (1978)) and precursors to these arguments can be found in Hogben (1933) and can also be found in R.A. Fisher’s work.) Lewontin claims that equation \((1’)\) above presents the most accurate picture of the contributions to phenotypic variance. He goes on to argue that \(V_{I}, V_{G\times E}\) and \(\COV(G,E)\) are not negligible. In fact, he argues that these are always part and parcel of the variance in traits. As a result, apportioning the phenotypic variance between genes and environment is no easy matter and standard analyses of variance simply cannot come up with useful and informative values for \(h_b^2\) and \(h^2\). Lewontin also points out that many proponents of heritability measures mistakenly attribute the heritability values to individuals rather than populations. Further, he argues that norms of reaction gave a more accurate picture of the relations between genes, environment and phenotypic traits. A norm of reaction is a graph of a quantitative phenotype plotted as a function of environment for different genotypes. Many philosophers and biologists have extended and refined Lewontin’s criticism of the analysis of variance (e.g. Block 1995, Kitcher 1985, Sarkar 1998, Sober 1988, Northcott 2006) and most share his conclusions that heritability measures are hard to come by and that norms of reaction are a superior way to examine gene/environment interactions.