I went to a lecture put on by my archdiocese called "Evolution and Ethics" (or something similar). I posted extensive notes and commentary in my journal, but it's friends-only, so I will post it here. With an LJ-cut, of course. This is the first of three posts I've made (so far, at least) on the lecture.
Since this post consists of notes, it will likely read as being a little unfocused; it's not an essay, just ... notes, with commentary thrown in. I decided to break it into several posts.
The speaker was a historian named Richard Weikart, and copies of an article of his entitled Does Darwinism Devalue Human Life? were distributed. He was invited to speak after Archbishop Chaput read his book From Darwin to Hitler: Evolutionary Ethics, Eugenics and Racism in Germany. At the opening of the lecture, he answered my biggest questions by quickly pointing out that his title is not his thesis, that he doesn't argue that Darwinism inevitably leads to Nazism or eugenics. He also pointed out he is approaching the subject from a historical perspective, that is, outlining what actually happened, not what should have happened or could have happened.
He gave a name to a concept I have had and argued, but never had a title for: the Naturalistic Fallacy. As he summed it up, it means "you can't go from an 'is' to an 'ought'." In other words, just because something is observed in nature to be true does not mean it should be applied to human ethics. For instance, it is a fact that a male lion will kill the cubs of another male so their mothers will come into heat and he can mate with them; it does not follow that a human male has a right to similarly kill children. It's a fact that less fit animals will tend to leave fewer offspring; it does not follow that human society should try to prevent the "less fit" among us from having children.
Weikart outlined several concepts developed by early Darwinists based on the Darwinist model of evolution by natural selection.
1. The animal ancestry of humans. Instead of viewing humans as a fundamentally different order of creation from animals, Darwinists began to view humans as a higher order of animals.
2. Denial of the body-soul dualism. Christian theists believed (and still do) that humans are comprised of both a physical body and spiritual soul; Darwinists denied there was a separate spiritual component unique to humans.
3. Moral relativism undermining human rights. If humans are merely advanced animals, then human rights are not inherent or God-given.
4. Human inequality. After all, Darwinism states that there is variety in a population, and the varieties have differential levels of fitness; social Darwinists applied that concept to humans to produce "superior" and "inferior" humans. Incidentally, literally everyone who was white and Western was racist a century ago. Social Darwinists actually argued that the difference between the "highest" humans (white Europeans, of course) and the "lowest" humans (Africans, of course) was less than the difference between the "lowest" humans and the "highest" animals (apes). These ideas that are so repugnant to us a century later were mainstream at one time.
5. Human struggle for existence. The resources of society are limited, after all, and the "inferior" are less adept at acquiring and using those resources.
6. Death as progress, that is, death produces good. It does so by culling the "inferior," improving the quality of the whole of the human race. Taken to its logical conclusion, this idea leads to Hitler's extermination camps.
With this intellectual foundation, it is no wonder eugenicists were so common and powerful at one time. I must point out and emphasize this crucial distinction (which Weikart also mentioned but did not dwell upon enough, in my opinion): Darwinism operates from natural selection, while eugenics operates from artificial selection. In other words, social Darwinism isn't actually Darwinist at all.