All of economics is divided into two schools: steady state theory and infinite planet theory. They can’t both be right. You’d think the choice between them would be obvious, but infinite planet theory still holds sway in classrooms and in the halls of power where policy is made. Last month, though, brought a significant development: the manager of a major hedge fund registered a carefully reasoned dissent from infinite planet theory. And in doing so, Jeremy Grantham offered a glimpse of how and why steady state economic theory will ultimately come to prevail.