There’s a lot of talk lately by Summers, Krugman, and others that we may be in a period of secular stagnation, in which the rate at which the economy grows in the wealthiest countries falls substantially and permanently. Observing this, some are quick to point to demography as the cause. If populations are not growing as swiftly as they once did, it would indeed make sense that growth rates would fall. Under this thinking, slower growth isn’t a problem, because per capita growth is theoretically still strong–the economy is growing slower in aggregate, but it’s growing at the same speed relative to the size of the population. The trouble is that on further investigation, the demographic explanation does not sufficiently account for what’s going on. Not only are growth rates slowing, but per capita growth rates are slowing, and have been slowing for a while, beginning far before the recent economic crisis. This throws Kurzweil’s theory of accelerating returns into doubt, and undermines the central precept underlying our capitalist society–that the labors of this generation today are meant to make the next generation’s lives go better. If stagnation is the way of the future, it’s a much more serious problem than we presently recognize, one that ultimately threatens not merely our dreams of better lives for ourselves, but the very stability of our civilization.