Mr Gordon is right that the second industrial revolution involved never-to-be-repeated changes. But that does not mean that driverless cars count for nothing. Messrs Erixon and Weigel are also right to worry about the West ’ s dismal recent record in producing new companies. But many old firms are not run by bureaucrats and have reinvented themselves many times over: General Electric must be on at least its ninth life. And the impact of giant new firms born in the past 20 years such as Uber, Google and Facebook should not be underestimated: they have all the Schumpeterian characteristics the authors admire. On the pessimists ’ side the strongest argument relies not on closely watching corporate and investor behavior. but rather on macro-level statistics on productivity. The figures from recent years are truly dismal. Karim Foda, of the Brookings Institution, calculates that labor productivity in the rich world is growing at its slowest rate since Total factor productivity (which tries to measure innovation) has grown at just 0.1% in advanced economies since 2004, well below its historical average. Optimists have two retorts. The first is that there must be something wrong with the figures. One possibility is that they fail to count the huge consumer surplus given away free of charge on the internet. But this is unconvincing. The official figures may well be understating the impact of the internet revolution, just as they downplayed the impact of electricity and cars in the past, but they are not understating it enough to explain the recent decline in productivity growth. Another, second line of argument that the productivity revolution has only just begun is more persuasive. Over the past decade many IT companies may have focused on things that were more “fun than fundamental ” in Paul Krugman’s phrase.But Silicon Valley ’s best companies are certainly focusing on things that change the material world. Uber and Airbnb are bringing dramatic improvements to two large industries that have been more or less stuck for decades. Morgan Stanley estimates that driverless cars could result in $507 billion a year of productivity gains in America, mainly from people being able to stare at their laptops instead of at the road. What has led to the pessimistic opinion concerning the world ’s economy? A.It is based on macro-level statistics on productivity. B.It is based on close observation on corporate and investor behavior. C.It is due to the fact that many old firms are not run by bureaucrats. D.It is due to the fact that not enough new firms have been created. The first argument on the optimists ’ side is unconvincing because the official figures ________.A.are both wrong and unconvincing B.downplay the internet revolution C.fail to include the consumer surplus D.can’t explain the decline in productivity growth What is true about the IT companies in Silicon Valley?A.They have only focused on the fun part of life. B.They have made a difference in the real world. C.They have more persuasive productivity. D.They have only just begun to develop. How can driverless cars benefit American industries?A.Driverless cars have revived two large American industries. B.The sale of driverless cars can reach hundreds of billion dollars. C.Thanks to them people free from driving can do more creative work. D.Driverless cars have stimulated the development of Uber and Airbnb.