 In the above simple, “deterministic” models, if we set the fitness parameters such that \(w_{D} &gt; w_{H} &gt; w_{R},\) the \(A\) allele spreads throughout the population, together with whatever traits it causes. Suppose we include within the purview of Darwin’s theory models of this sort, together with the systems they (approximately) govern. If we change the value of the fitness coefficients such that \(w_{D} &lt; w_{H} &gt; w_{R},\) the system will exhibit a different sort of dynamics. It will evolve to an equilibrium point, where there exist some \(A\) alleles as well as some \(a\) alleles in the population, and remain there, resulting in a stable polymorphism. If we hold evolution as a condition for selection, we will issue the curious ruling that a system governed by the first sort of model falls within the scope of evolutionary theory while a system governed by the second sort of model only does so up until it reaches a stable intermediate state but then no longer. Moreover, populations exhibiting stable polymorphisms resulting from heterozygote superiority, or overdominance, are just one case among many different sorts of systems that equally exhibit stable polymorphisms.