Central banks are afraid of stable prices for two reasons. The first is that the real value of debt automatically increases when prices fall. But fears of debt deflation seem overblown: because nominal interest rates are themselves close to zero, the real burden of debt would not increase even if prices remained stable. Moreover, the manageability of debt service depends mainly on whether incomes increase faster than the outstanding debt, not on whether the inflation rate exceeds the interest rate.
https://www.project-syndicate.org/commentary/ecb-deflation-obsession-by-daniel-gros-2019-09
