David Boaz at Cato provides this insight about Keynes thinking on the economy:
Drama was a Keynes tool. During a 1934 dinner in the U.S., after one economist carefully removed a towel from a stack to dry his hands, Mr. Keynes swept the whole pile of towels on the floor and crumpled them up, explaining that his way of using towels did more to stimulate employment among restaurant workers.
Bastiat exploded this myth with his parable of the broken window in 1850 but it seems to make a comeback every time there is a hurricane or some other natural disaster. You cannot create wealth by first destroying it.