He proposed that every feature in a human—height, weight, intelligence, beauty—was a composite function generated by a conserved pattern of ancestral inheritance. The parents of a child provided, on average, half the content of that feature; the grand-parents, a quarter; the great-grandparents, an eighth—and so forth, all the way back to the most distant ancestor. The sum of all contributions could be described by the series—½ + ¼ + ⅛ . . .—all of which conveniently added to 1. Galton called this the Ancestral Law of Heredity.
