“…How, though, to distinguish the eugenically fit from the unfit? As a “rough-and-ready” method, Huxley liked the idea of using salaries: the higher the salary, the fitter the person. That was simple enough, but it led to a eugenic conundrum. Wealthy people had fewer children on average than poor people. Professionals and landowners had fewer children than unskilled laborers. You might think it would have occurred to Huxley that in strictly Darwinian terms, the laborers’ higher reproductive rate meant they were the more fit, since for Darwin “fitness” simply meant reproductive success. But apparently not. Instead, he lamented that those with a relatively “poor physique and low mental type” were reproducing like crazy while those whose spots at Oxford had come to them with their birth certificates were having maybe just two children. This would lead to “a progressive deterioration of the average of the national stock.”
Huxley offered an illustration that was Mendelian in its mathematical elegance: suppose that for every 100 laborers, three were outstanding and seven defective, while for every 100 professionals, seven were outstanding and three defective. Then suppose that the professional class remains about the same size while the laboring class doubles every two generations. In the original generation, outstanding and defective people each make up five percent of the overall population; but after two generations, the percentages would be 3.8 and 6.2, and after five, they would be three and 6.8, and so on. You can see where this is going. Moreover, this was assuming “no migrations between class and class occurred, which would make things worse.”
The same problem preoccupied Ronald Fisher, an English mathematician and geneticist whose work was foundational to the modern synthesis. Fisher asserted (on no evidence) that inheritance was strictly “particulate”; that mutations were effectively random, having no shaping forces or causes; and that biologists should just face the fact that natural selection was the only mechanism directing evolution. Yet natural selection didn’t seem to be doing a great job of it. Fisher, too, worried about poor people having more children than rich people, which he called the “inverted birth-rate.” He was a devout Anglican, but he doesn’t seem to have trusted his God to cope with the situation either. Convinced that social classes were “genetically differentiated,” he fretted that the current trend was leading to a degradation of the human race.
This was no idle speculation; Fisher meant to do something about it. During his career, he served as the inaugural chairman of the University of Cambridge Eugenics Society, held the position of Galton Professor of Eugenics and head of the Department of Eugenics at University College London, and edited the journal Annals of Eugenics. He was a man of action. As a solution to the inverted birth-rate problem, for instance, Fisher proposed that the state make family allowances proportional to salaries: the higher the salary, the higher the allowance. This would encourage the rich to breed more and the poor to breed less. Leonard Darwin, a son of Charles Darwin, had made a similar proposal, suggesting income tax rebates to families who had more children, since only wealthier professionals paid income taxes. But he had cautioned that it would be essential for state administrators to verify that no artisans or laborers had made it into the class paying income taxes and therefore receiving the rebates…”