[mlsu]

Piketty argues that if r > g, wealth will accumulate into fewer and fewer hands over time. R is the rate of return of capital (rents, stocks, bonds, etc) and g is the growth of the economy over time.

If the economy grows at a higher rate than the rate of return, the pie gets bigger at a higher rate than wealth can concentrates. If the rate of return accumulates capital at a higher rate than the growth of the economy, wealth will inevitably concentrate over time.

He uses a lot of examples and economic history to argue that r > g, except for a few small periods. I think given the amount of wealth concentration we are seeing, and the political effects thereof, it is a compelling argument. Taxation (of wealth) is the proposed solution.