Economists and historians have varied explanations for what set off the industrial bomb. Most are quantitative in nature: They focus on the expansion of the labor market, on new inventions, or on new patterns of trade or investment. As Deirdre McCloskey, an economist at the University of Illinois at Chicago sees it, it was culture, not economics, that lit the fuse. In her new book, “Bourgeois Dignity: Why Economics Can’t Explain the Modern World,” she argues that changing attitudes toward innovation and money-making, rather than changing technologies or markets, unleashed industrialization.