Presidential address for the Twelfth World Congress of the International Economic Association, summarising semi-formally the author’s recent work and concerns. Uncertainty and incomplete markets breed demand volatility as well as price and wage rigidities. The conjunction of these leads to multiple, volatile supply-constrained equilibria, typically reflecting coordination failures and apt to display persistence – as documented by three supporting theorems. Specific implications are linked to the conclusions that we should take coordination failures seriously, try to obviate demand volatility and try to by-pass price and wage rigidities.
