HOW much yarn per day could an 18th-century British woman spin? Such questions are catnip for economic historians, whose debates typically unfold unnoticed by anyone outside their field. But a running debate concerning the productivity of pre-industrial spinners, and related questions, is spilling beyond academia. Each probably produced between a quarter of a pound and a pound of yarn a day, the historians have concluded. But at issue is something much more profound: a disagreement regarding the nature of technological progress that has important implications for the world economy.
Economic growth of the sort familiar today is a staggering departure from the pattern of pre-industrial human history. More than a century of study has not resolved the question of why it began where and when it did. This is a matter of more than historical interest. Weak growth in productivity has economists asking whether humanity is running out of ideas, and whether it is losing its ability to turn new…
