Despite their differences on other questions, Hume and Steuart had almost identical theories of long-run economic development. In their story, agriculture can produce a surplus of food to support urban manufacturing (and other things), but will not do so unless farmers want to trade the surplus...

<italic>Everyone has to eat, so agriculturalists must produce enough to feed themselves and the rest of the population. This statement is trivially obvious but making it explicit mattered to the early development of economic thinking. Many important economic writers of the period (Petty, Cantillon,...</italic>