I’m currently reading Robert J. Gordon’s important new book, The Rise and Fall of American Growth: The U.S. Standard of Living since the Civil War, published by Princeton University Press. (You can read the first chapter here.) Gordon, 75, professor of economics at Northwestern University, is a leading expert on productivity and economic growth. He’s a member of the National Bureau of Economic Research’s business cycle dating committee, which all but officially decides when U.S. recessions begin and end.

I haven’t yet reached the headline sections of the book, in which Gordon argues that for various structural reasons the United States will never again reach the same rates of growth it experienced in the 20th century—a forecast that’s bad news for everybody, given the nasty turn U.S. politics have taken during the slowdown induced by the 2008 crash. I’m sure once I get to those chapters I’ll be tempted to add my voice to what has already been a flood of comment on whether that forecast is correct or not.

For now I’m still working through the early chapters, in which Gordon looks in detail at the technological changes the U.S. went through between 1870 and 1940, a period he thinks is truly unprecedented, not just in U.S. but in world history, marking as it did both mass urbanization and mass mechanization, two crucial human transitions that can only be experienced once. We’re so taken up these days with the very latest twists in cellphone technology that we forget just how (literally) epoch-making some of these earlier changes were. Senator Marco Rubio, now a former candidate for the Republican nomination for president, liked to talk about how his grandfather was born in 1899, before the Wright brothers, but nevertheless lived to see a person walk on the moon. Indeed.

Gordon’s early chapters are full of interesting tidbits about life as it used to be. For instance, window screens weren’t invented until the 1870s. Before that nothing prevented insects “from commuting back and forth between animal waste and the family dinner table.” Nor was the largely horse-drawn society of that era a bucolic green nirvana: “Horses dropped thousands of tons of manure and gallons of urine on city streets; died in service, leaving 7,000 horse carcasses to be carried away each year in Chicago alone; and carried diseases transmissible to humans.” In the late 1800s, roughly one quarter of U.S. farmland was devoted to growing horse feed.

For some reason the detail that caught my eye concerned the subway and elevated train cars that began to replace horse-drawn carriages in the biggest U.S. cities in the 1890s. To begin with, the car doors in subways and “els” could only be closed manually. In most places, there was therefore a conductor for every two cars to open and close the doors at each and every stop (much as there were elevator operators in every one of the hundreds of new highrises shooting skyward in America’s cities).  

I suppose a job like subway door-opener had its compensations. You did get paid. And you presumably met a lot of people, however briefly. But you worked underground all day; it must have been very tiring, depending on how heavy the doors were; and it can only have been monotonous. (As Friedrich Engels put it in The Condition of the Working-Class in England, the mission of the factory worker “is to be bored every day and all day long from his eighth year.”)

Is anyone really sorry that the job of door-opener on subways and els has been made technologically obsolete? The job wasn’t unimportant: There are significant productivity gains all round when passengers aren’t permanently trapped inside the conveyances that get them where they want to go. But if door-openers can be freed up to do other things, that’s likely to be good for everyone, door-openers included. Maybe not in the short run. But forever after that.

Gordon doesn’t say anything about when the transition to automated doors came or how it was received by door-openers or their unions, if they had unions. If door-opening is all you’ve ever done and you’ve reached an age where your alternatives have mainly dried up, it’s easy to understand how you might be very upset by new subway or rail cars with self-opening doors and want to resist their introduction. But in the long view it’s surely best that if machines can do the drudge work, people be freed from it.   

We hear a lot these days about the terrible job-destroying effects of innovation and also trade. But for the long haul, job destruction is precisely what we want. The policy problem is figuring out ways to ease the transition for the last holders of jobs whose disappearance is no tragedy.