The Parable of the broken window;
Have you ever witnessed the anger of the good shopkeeper,
James Goodfellow, when his careless son has happened to
break a pane of glass? If you have been present at such a
scene, you will most assuredly bear witness to the fact
that every one of the spectators, were there even thirty
of them, by common consent apparently, offered the
unfortunate owner this invariable consolation – "It is an
ill wind that blows nobody good. Everybody must live, and
what would become of the glaziers if panes of glass were
never broken?"
Now, this form of condolence contains an entire theory,
which it will be well to show up in this simple case,
seeing that it is precisely the same as that which,
unhappily, regulates the greater part of our economical
institutions.
Suppose it cost six francs to repair the damage, and you
say that the accident brings six francs to the glazier's
trade – that it encourages that trade to the amount of
six francs – I grant it; I have not a word to say against
it; you reason justly. The glazier comes, performs his
task, receives his six francs, rubs his hands, and, in
his heart, blesses the careless child. All this is that
which is seen.
But if, on the other hand, you come to the conclusion, as
is too often the case, that it is a good thing to break
windows, that it causes money to circulate, and that the
encouragement of industry in general will be the result
of it, you will oblige me to call out, "Stop there! Your
theory is confined to that which is seen; it takes no
account of that which is not seen."
It is not seen that as our shopkeeper has spent six
francs upon one thing, he cannot spend them upon another.
It is not seen that if he had not had a window to
replace, he would, perhaps, have replaced his old shoes,
or added another book to his library. In short, he would
have employed his six francs in some way, which this
accident has prevented.
Frédéric Bastiat,
in his 1850 essay "Ce qu'on voit et ce qu'on ne voit pas"
(That Which Is Seen and That Which Is Not Seen)
https://en.wikipedia.org/wiki/Parable_of_the_broken_window