As with every question in social science, correlation is not causation. Do better-educated countries get richer, or can richer countries afford more education? One way to cut the know is to take advantage of the fact that a cause must precede its effect. Studies that assess education at Time 1 and wealth at Time 2, holding all else constant, suggest that investing in education really does make countries richer. At least it does if the education is secular and rationalistic.

Steven Pinker, Enlightenment now: the case for reason, science, humanism, and progress, New York, 2018, p. 234