Here is a short piece by Henry Hazlitt from his book Economics in One Lesson called “The Broken Window” Maneuver :
A young hoodlum breaks the window of a bakery and the gathered crowd begins to philosophize about whether the hoodlum really harmed anyone at all since he, after all, created employment.
He created employment by having to force the baker to pay the $250 it costs to fix the window to the window repair man. The window repair man will then have an extra $250 to spend with other merchants and those merchants will have more money to spend elsewhere. This line of thinking can continue on forever.
If it weren’t for the broken window then the window repair man would have less money and employment and so would the merchants he would spend the money with and so on.
So, what do you think? Should we stimulate the US (indeed, world) economy, simply by arming our population with rocks and asking them to all go break windows?