While "survival of the fittest" implies species improvement in the hit and miss natural state, "selective breeding" arrives at the same end much faster and by design. Selective breeding produces purebred dogs, cattle, race horses. It has been going on for a very long time and is a well-accepted practice.
But what about "pedigree" in humans?
Eugenics is the study and practice of selective breeding applied to humans. The aim is the same: improvement of the species. This usually really means "improving human genetic qualities." Advocates of eugenics seek to purify the human gene pool. Like thoroughbred horses, only humans.
Can this be a way to eradicate disease? Increase average IQ? Create a race of super humans?
Of course, just as in dog breeding, one would have to cull the litter. Not only would you have to choose the best male and females to mate, you would have to destroy the weak and sickly and defective, so they couldn't breed and contaminate the super race.
Germany following World War One was ripe for a Hitler, I have postulated, because of a need for both a savior and a scapegoat to achieve some sort of national redemption. Hitler was the savior; the Jews were the scapegoat. It goes deeper than that, though. If you read about the Thule Society, as suggested in an earlier post, then you know a little bit of background on the Aryan or Indo-Aryan race theories that seemed to be held by Hitler and his cronies.
During the 1920s and 1930s, a huge number of "dispossessed" run-of-the-mill Germans seemed to have bought into this "super race" theory as well. If you are a doormat, perhaps you dream of being something more worthy and special again; perhaps you become disposed to listen to people who promise to lead you back to self-respect, even greatness. People like Hitler and Goebbels. Perhaps you join the Nazi party. Perhaps you don't, but you believe anyway.
The Jews were only the beginning. There was a long list of "mongrels" and weaklings that would need to be purged if the Aryan race was to rise to its proper place in the scheme of human Natural Selection.
"Life unworthy of life"
Between 1939 and 1945, the German SS systematically killed between 11 and 14 million people.
The murder of 6 million Jews is well-known, but the list was much longer than Jews. Non-Jewish Poles, Communists, political opponents, members of resistance groups, homosexuals, Roma ("Gypsies"), the physically handicapped, the mentally deficient, Soviet prisoners of war (perhaps as many as 3 million), Jehovah's Witnesses, Adventists, trade unionists, psychiatric patients. And this doesn't even count the people who died simply of slave labor, starvation and disease in concentrations camps, and as a result of medical experimentation.
The first to go were the children with physical or developmental disabilities.
Then there were the medical experiments.
I sincerely hope your mind and sensibilities are such that you cannot begin to imagine the extent of these ghoulish horrors. Descriptions and even photos are available on the web. Do yourself a favor and don't look them up. I almost puked.
Quite simply, the Nazi doctors tortured Jewish and Gypsy children, and many others. Operations without anesthetics, "patients" put in pressure chambers, drug testing, castrations, frozen to death and exposed to countless traumas. The "Angel of Death", Josef Mengele, had his own infamous experiments on twins. Afterwards they were usually murdered and dissected.
After the war, many of Hitler's henchmen were tested and found to be quite psychologically normal. They were men of fine standing in their communities. They were husbands who kissed their wives. They were fathers who tucked their children into bed.
Then they went out and tortured little children, brutalized women, gassed millions, performed hideous experiments.
The word "villain" falls short here, if we are looking for sources of literary character development.
No, here we get into the realm of unspeakable monsters; things you are afraid to look at in the dark; real-life Bogeymen.