How do wealth- and capital-output ratios evolve in the long run, and why? Until recently it was difficult to properly address this question, for one … - Thomas Piketty

The overall importance of capital today, as noted, is not very different from what it was in the eighteenth century. Only its form has changed: capital was once mainly land but is now industrial, financial, and real estate. We also know that the concentration of wealth remains high, although it is noticeably less extreme than it was a century ago. The poorest half of the population still owns nothing, but there is now a patrimonial middle class that owns between a middle and a third of total wealth, and the wealthiest ten percent now own only-two thirds of what there is to own rather than nine-tenths.

Economists are all too often preoccupied with petty mathematical problems of interest only to themselves. This obsession with mathematics is an easy way of acquiring the appearance of scientificity without having to answer the far more complex questions posed by the world we live in.

We know something about billionaire consumption, but it is hard to measure some of it. Some billionaires are consuming politicians, others consume reporters, and some consume academics.