Facts Rarely Speak for Themselves

The richest families in Florence in 1427 are still the richest families in Florence is the headline of a story describing some interesting research in economic history. I have not read the article it is based on but, assuming the report is correct, its conclusion is that there is a close correlation between the last names of the wealthiest Florentine families in 1427 and the last names of those currently wealthy. There are at least two quite different interpretations of the reported facts. One is that families are surprisingly good at passing wealth and status down from one generation to another. The other is that the characteristics that produce wealth and status are to a large extent heritable. One problem for the second is that last names are passed down in the male line, while talents are passed down through both sons and daughters—a fact observed by Galton more than a century ago. A family could choose to exclude daughters from inheritance of wealth but not of talent. But that is a less serious problem than it at first appears, because high status women mostly married high status men. The daughter of a wealthy Florentine family would usually combine her genetic heritage with the last name of a husband from a different wealthy Florentine family. Hence both genetic advantages and wealth would for the most part remain, from generation to generation, associated with the same pool of last names.The story illustrates a general point: Facts rarely speak for themselves. How you interpret new facts depends on the picture of the world you fit them into.