Because Darwinism gave a new explanation for how and why each organism is so well adapted to its environment, this enormous record of convergence surely must say something as well about the environment. In other words, the fact that so many biological forms developed photosensitive cells and then eyes (or their equivalents) also testifies to the ubiquity of light, just as the fact that wings developed independently on insects, birds, bats, some dinosaurs, and so forth, testifies to the density and viscosity of the atmosphere of the earth. So too with complex brains: to be adaptive, brains have to evolve in response to the environment. In other words, if wings evolve over against and in response to air and eyes over against and in response to light, then brains must evolve over against and in response to something like “mental air.” By that admittedly metaphorical term I mean those a priori ideal structures already part of the universe that make a mathematics-capable brain possible in the first place. In other words, Darwinism is not only compatible with Platonism, it presupposes it.
It cannot be the burden of this chapter to establish the argument and grounds for advocating such a “Darwinian Platonism,” except perhaps to say that a denial of this thesis would run into the difficulty of suddenly finding that the human brain, alone of all organs and organism, is not adapted to its environment and did not evolve over against any selecting force in nature, the way air and light work for wings and eyes respectively. I should also perhaps add that arguments for Platonism , when reinforced by Darwinian perspectives, can help heal the neuralgia currently afflicting atheist Darwinians like Richard Dawkins whenever they hear the word religion. For that reason, the Platonic implications of Darwinian theory will often be resisted for just this reason by atheists, but that is to argue against the conclusion on prior grounds, not against the evidence or the logic of Darwinism.
-Edward T. Oakes, SJ, "Complexity in Context"
Father Oakes has commented on this elsewhere. Quoting Daniel Dennett:
It has often been pointed out that Plato's curious theory of reincarnation and reminiscence, which he offers as an explanation of the source of our a priori knowledge, bears a striking resemblance to Darwin's theory, and this resemblance is particularly striking from our current vantage point. Darwin himself famously noted the resemblance in a remark in one of his notebooks. Commenting on the claim that Plato thought our "necessary ideas" arise from the pre-existence of the soul, Darwin wrote: "read monkeys for preexistence."