[W]hat mattered were two levels of ideas -- the ideas in the heads of entrepreneurs for the betterments themselves (the electric motor, the airplane, the stock market); and the ideas in the society at large about the businesspeople and their betterments (in a word, that liberalism). What were not causal were the conventional factors of accumulated capital and institutional change. They happened, but they were largely dependent on betterment and liberalism.

The upshot since 1800 has been a gigantic improvement for the poor, yielding equality of real comfort in health and housing, such as for many of your ancestors and mine, and a promise now being fulfilled of the same result worldwide -- a Great Enrichment for even the poorest among us.

These are controversial claims. They are, you see, optimistic. [...]

For reasons I do not entirely understand, the clerisy after 1848 turned toward nationalism and socialism, and against liberalism. It came also to delight in an ever expanding list of pessimisms about the way we live now in our approximately liberal societies, from the lack of temperance among the poor to an excess of carbon dioxide in the atmosphere. Anti-liberal utopias believed to offset the pessimisms have been popular among the clerisy. Its pessimistic and utopian books have sold millions.

But the twentieth-century experiments of nationalism and socialism, of syndicalism in factories and central planning for investment, of proliferating regulation for imagined but not factually documented imperfections in the market, did not work. And most of the pessimisms about how we live now have proven to be mistaken.

It is a puzzle. Perhaps you yourself still believe in nationalism or socialism or proliferating regulation. And perhaps you are in the grip of pessimism about growth or consumerism or the environment or inequality. Please, for the good of the wretched of the earth, reconsider. The trilogy chronicles, explains, and defends what made us rich -- the system we have had since 1800 or 1848, usually but misleadingly called modern "capitalism."

The system should rather be called "technological and institutional betterment at a frenetic pace, tested by unforced exchange among all the parties involved." Or "fantastically successful liberalism, in the old European sense, applied to trade and politics, as it was applied also to science and music and painting and literature." The simplest version is "trade-tested progress."

Many humans, in short, are now stunningly better off than their ancestors were in 1800. And the rest of humanity shows every sign of joining the enrichment. A crucial point is that the greatly enriched world cannot be explained in any deep way by the accumulation of capital, as economists from Adam Smith through Karl Marx to Varoufakis, Piketty, and Cowen have on the contrary believed, and as the very word "capitalism" seems to imply.

The word embodies a scientific mistake. Our riches did not come from piling brick on brick, or piling university degree on university degree, or bank balance on bank balance, but from piling idea on idea.