 In population genetics, the complexities of development in its ecological context are also collapsed into the parameters of the models, such as the parameters for surviving and leaving offspring. Not surprisingly then, the estimation of the selection coefficients of genotypes (in the sense of pairs of genes) is more readily done when the populations are subject to artificial selection in the laboratory than when frequencies or changes over time are observed in the wild. Lewontin (1974a) provides grounds for doubting the likelihood of some day restoring what is abstracted away in those selection coefficients. Measurements of selection coefficients and other parameters of the model are possible, Lewontin concludes, only when a single allelic substitution is associated with a large difference in the trait, not when the effects of gene substitutions make only small differences. This led him to remark that: “What we can measure is by definition uninteresting and what we are interested in is by definition unmeasurable” (1974a: 23). The problem of relating population genetic models to observations becomes astronomically worse when there are multiple, linked loci (1974: 317). He suggests that population genetics should shift its attention to the selection coefficients for long segments of chromosomes. This program, like Johannsen’s wish that the genotype be seen as a whole, has scarcely been pursued. Even if it had been, ecological genetic analysis of variation in natural populations, with all its complexity (e.g., Clausen et al. 1948), would still be needed to begin to reintegrate ecological context into population genetics. 