Deirdre McCloskey is right: the emergence of a new rhetoric, ideology, or set of ideas was an important factor in the rise and development of capitalism.
A big change in the common opinion about markets and innovation, I claim, caused the Industrial Revolution, and then the modern world. The change occurred during the seventeenth and eighteenth centuries in northwestern Europe. More or less suddenly the Dutch and British and then the Americans and the French began talking about the middle class, high or low — the “bourgeoisie” — as though it were dignified and free. The result was modern economic growth.
The mistake she makes is to presume that rhetoric is incompatible with materialism. In fact, ideas are just as material as anything else in shaping and transforming society.
In my view, the emergence of new subjectivities was crucial to the initial emergence, and later growth and development, of capitalism. And new, bourgeois subjectivities were (and remain) dependent on bourgeois languages and ways of looking at and talking about the world. But, and this is what McCloskey forgets, one of the conditions of existence of bourgeois rhetoric (as well as bourgeois subjectivities and much else) is a social surplus—initially appropriated and distributed from noncapitalism, later from within capitalism itself.
Both rhetoric and surplus play discreet but important roles in a materialist explanation of the rise of the bourgeoisie.