权力和科学结合在一起会产生邪恶的后果。印欧语系被确立之后，人类学家生物学家语言学家都在寻找文化源头，最终确立3000年前从中亚入侵印度的Arya雅利安人是印欧语系的源头。接下来配合着达尔文物竞天择的演化论，欧洲学者将雅利安人从一个原始语言群体转变成文化，种族全面优秀的存在。紧接着就开始形成了纯种人类理论，为了保持欧洲雅利安人的血统纯洁，必须进行种族清洗。
The main ambition of the Nazis was to protect humankind from degeneration and encourage its progressive evolution. This is why the Nazis said that the Aryan race, the most advanced form of humanity, had to be protected and fostered, while degenerate kinds of Homo sapiens like Jews, Roma, homosexuals and the mentally ill had to be quarantined and even exterminated.
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Given the state of scientific knowledge in 1933, Nazi beliefs were hardly outside the pale. The existence of different human races, the superiority of the white race, and the need to protect and cultivate this superior race were widely held beliefs among most Western elites. Scholars in the most prestigious Western universities, using the orthodox scientific methods of the day, published studies that allegedly proved that members of the white race were more intelligent, more ethical and more skilled than Africans or Indians. Politicians in Washington, London and Canberra took it for granted that it was their job to prevent the adulteration and degeneration of the white race, by, for example, restricting immigration from China or even Italy to ‘Aryan’ countries such as the USA and Australia.
From Sapiens