Caricature from 1871 Vanity Fair
Political interpretations
Darwin’s theories and writings, combined with Gregor Mendel’s genetics (the “modern synthesis”), form the basis of all modern biology. However, Darwin’s fame and popularity led to his name being associated with ideas and movements which at times had only an indirect relation to his writings, and sometimes went directly against his express comments.
Eugenics
For more details on this topic, see Eugenics.
Darwin was interested by his half-cousin Francis Galton's argument, introduced in 1865, that statistical analysis of heredity showed that moral and mental human traits could be inherited, and principles of animal breeding could apply to humans.
In The Descent of Man Darwin noted that aiding the weak to survive and have families could lose the benefits
of natural selection, but cautioned that withholding such aid would endanger the instinct of sympathy,
"the noblest part of our nature",
and factors such as education could be more important.
When Galton suggested that publishing research could encourage intermarriage within a "caste" of "those who
are naturally gifted", Darwin foresaw practical difficulties, and thought it "the sole feasible, yet I fear utopian, plan of procedure in improving the human race", preferring to simply publicise the importance of inheritance and leave decisions to individuals.
Galton named the field of study Eugenics in 1883, after Darwin’s death, and developed biometrics. Eugenics movements were widespread at a time when Darwin's natural selection was eclipsed by Mendelian genetics, and in some countries including Belgium, Brazil, Canada, Sweden and the United States, compulsory sterilisation laws were imposed. Nazi eugenics in Germany discredited the idea.