Capital in the Twenty-First Century

by Thomas Piketty

For example, when David Ricardo formulated in 1817 the hypothesis known today as “Ricardian equivalence,” according to which, under certain conditions, public debt has no effect on the accumulation of national capital, he was obviously strongly influenced by what he witnessed around him. At the moment he wrote, British public debt was close to 200 percent of GDP, yet it seemed not to have dried up the flow of private investment or the accumulation of capital. The much feared “crowding out” phenomenon had not occurred, and the increase in public debt seemed to have been financed by an increase in private saving. To be sure, it does not follow from this that Ricardian equivalence is a universal law, valid in all times and places. Everything of course depended on the prosperity of the social group involved (in Ricardo’s day, a minority of Britons with enough wealth to generate the additional savings required), on the rate of interest that was offered, and of course on confidence in the government. But it is a fact worth noting that Ricardo, who had no access to historical time series or measurements of the type indicated in Figure 3.3 but who had intimate knowledge of the British capitalism of his time, clearly recognized that Britain’s gigantic public debt had no apparent impact on national wealth and simply constituted a claim of one portion of the population on another.15