Assume that thousands of travelers set out from Chicago,selecting their roads completely at random and without foresight. Only our '(economist" knows that on but one road are there any gasoline stations. He can state categorically that travelers will continue to travel only on that road; those on other roads will soon run out of gas. Even though each one selected his route at random, we might have called those travelers who were so fortunate asto have picked the right road wise, efficient, foresighted, etc. Of course, we would consider them the lucky ones. If gasoline supplies were now moved to a new road, some formerly luckless travelers again would be able to move; and a new pattern of travel would be observed, although none of the travelers had changed his particular path.
those businesses most frequently combined do on average represent more efficient combinations than those that are rarely combined. The comparative-efficiency version of the survivor principle thus withstands our attempt at falsification.