Here I tried to show that Darwinism does not theoretically license any attempt to engineer humans to become more “fit,” e.g. eugenics, killing disabled people in the Holocaust, etc. I quoted where Darwin himself says the practice would violate morality.
I might have added: Darwin condemns it on practical grounds as well. In The Origin of Species, he writes:
“It is good thus to try in our imagination to give any form [i.e., adaptive feature] some advantage over another. Probably in no single instance should we know what to do, so as to succeed. It will convince us of our ignorance on the mutual relations of all organic beings; a conviction which is necessary, as it seems to be difficult to acquire.”
In other words, not only may we not “enhance” humanity through artificial (versus natural) selection, but it wouldn’t work if it we tried. We simply don’t know which adaptations will enhance fitness and which won’t. The situation is a bit game-theoretic: The complexity of an environment, which includes all of the other organisms, and all of the infinite ways it (and they) might change in the future, preclude a solid basis for “engineering.” This is precisely why the theory of evolution is not a predictive one. It locates a real causal mechanism for speciation, but it by no means follows that we can anticipate precisely how a species will change to come. Yet this is precisely what would be needed in order to “breed” humans for fitness. (We can sort of breed animals for fitness only to the extent they remain in a relatively artificially closed system of domesticity or captivity.)
Ben Stein, et.al.: Do we need any further evidence to prove that Darwinism does not contain the “seeds of horror”?