Do we need cash? Humen have utilized all sorts of things to exchange items of economic value — rare metals, strings of shells and even sunken boulders. Those objects have gotten more ephemeral, with paper money replacing most coins, and digital forms increasingly supplanting paper. Could physical cash go forth solely? Economists insure great payoffs in a cashless society: lower transaction costs, new tools to manage economic growth and an objective to tax evasion and money laundering. Critics consider an objective to privacy, frightening new powers for dictators and costs that would fall disproportionately on the poor. The giant, if unintended, experiment that followed India’s attempt to withdraw 86 percent of cash in circulation proved one thing clearly: The aim of cash is not likely to be a neat or simple process.