Francis Galton

The first man to put genius on a graph — drew the bell curve and read it backwards, calling the right tail "good blood."

Darwin's cousin and the most prolific data-collector of the 19th century. Hereditary Genius (1869) was the first attempt to measure exceptional ability statistically: he counted "eminent men," tracked their kinship lines, and concluded that genius runs in families. He was the first to apply the normal distribution to human traits — turning Quetelet's "average man" inside out by attending instead to the tails. He invented regression to the mean (his observation that exceptional fathers have less-exceptional sons), which alone should have killed his thesis since it contradicts hereditary fixedness — but he kept going. He coined eugenics in 1883. The math he gave us — correlation coefficient, regression line, percentile ranking, the standard deviation as a population measure — is the substrate of all later social science, psychometrics, and quality control. The conclusion he drew from it — that the right tail is a fixed bloodline — was wrong, and the cost of his being wrong runs through 20th-century policy from forced sterilization to immigration quotas. The mathematics he gave us is real; the moral he drew from it is the original sin of statistics.