On the other hand, economics seems to be all about exponential growth, which can't go on forever. For example, a seemingly modest growth rate of 2% is a doubl

On the other hand, economics seems to be all about exponential growth, which can't go on forever. For example, a seemingly modest growth rate of 2% is a doubling every 35 years (because 1.02^35=2). So once you've depleted a resource on earth, you'll consume another earth-equivalent in just 35 years. Then two earths. Then four, eight, sixteen,...