6 ideas
Real income per person has risen roughly sixteen- to thirtyfold since 1800, and more once you count quality improvements, after millennia of about $3 a day. A change of that size cannot come from gains of a few percent, such as better allocation, trade gains or reshuffling resources. It demands an explanation of equal size, and only sustained innovation fits.
Saving and investment happened in many societies without producing modern growth, and capital is easy to get once a profitable idea exists. Investment is therefore a response to innovation, not its source. Theories that make thrift or accumulation the engine mistake a routine input for the scarce spark.
The profits from slavery, colonialism and overseas trade were too small relative to national income to fund or explain the growth that followed. Redistributing wealth from victims moves existing value around; it does not multiply output per person by factors of ten. The poorest groups in innovating societies also gained enormously, which zero-sum exploitation cannot produce.
Property rights, rule of law and contract enforcement existed in many earlier societies, such as medieval Europe and imperial China, without a takeoff. Formal rules only work when people's beliefs and ethics give them meaning and legitimacy. Neo-institutionalist accounts that reduce rules to incentive constraints leave out the talk and values that make those rules operate.
McCloskey argues that society's rhetoric shifted, first in Holland around 1600 and then in Britain around 1700, to honor merchants, inventors and entrepreneurs instead of despising them, and to grant them liberty to try new things. Dignity meant how ordinary bourgeois people were regarded, and liberty meant freedom to innovate. In her account, together they encouraged widespread trial-and-error betterment, and that innovation drove the enrichment.
McCloskey treats persuasion and ethical talk as part of how economies work, faulting economists who model behavior through prudence and material incentives alone. On her reading, the historian should also study what a society says about commerce, what it praises and what it sneers at, and not just prices and endowments.