Brad DeLong (reviewing Joel Mokyr's A Culture of Growth: The Origins of the Modern Economy in Nature):
Economic history: The roots of growth: What is modern economic growth? Going by the best available measure (it might be more honest to say 'guess'), today's average material living standards and economic productivity levels are some 20 times what they were in the agricultural era (about 6000 BC to AD 1500). And the efficiency with which humanity uses technology and organization to transform resources into useful commodities is currently growing at 2% per year — perhaps 100 times the rate common before the Industrial Revolution.
Some think that the current rate will slow down. But very few see it coming to a rapid end, unless there is a nuclear war or an equivalent catastrophe. The slowing will come as low-hanging fruit is picked and resource scarcities bite; but resource exhaustion followed by crash, as described in Jay Forrester's 1971 World Dynamics (Wright-Allen Press), is likely only in systems in which scarce resources are not rationed by high prices.
What set the stage for industrial expansion and unleashed the virtuous spirals that drive growth? …