THIS week's print edition has a detailed look at recent arguments that rich-world economic stagnation is down to slackening technological progress. Tyler Cowen's notable e-book "The Great Stagnation" is a key piece of this literature, but the position has been reinvigorated thanks to a new paper by Robert Gordon. Mr Gordon's take on stagnation is considerably more pessimistic and forward-looking than Mr Cowen's; not only is an innovative slowdown responsible for slowing progress pre-crisis, he argues, but this trend will continue as the benefits from humanity's "one big wave" of innovation peter out amid demographic and fiscal headwinds.

I recommend reading our take in full but I'll summarise a bit here. It seems clear that productivity growth dropped sharply in the early 1970s relative to the earlier industrial era. At least part of that slowdown is probably due to the exhaustion of benefits from the great innovations of the past—electrification, internal combustion engines, petrochemicals, and the "early IT" of radio and telephones among them. Discovery didn't stop, of course, but the locus of innovation—computing and information technology—was simply too small a part of the overall economy to have a big effect on growth, incomes, and welfare.

By the mid-1990s, that was no longer the case. The computing age began to show up in the productivity statistics in a big way. This occurred, first, in the technology sector itself as America captured huge gains from production of chips, computers, and similar technology. By the early 2000s, however, productivity gains had shifted to the rest of the economy, as other sectors got better at using computers and the nascent web.

As of 2005, however, something seemed to go wrong. Productivity in manufacturing slipped a bit and dropped substantially for the economy as a whole. The 2000s were also a trying period in terms of employment and wage growth. This has led some thinkers, including Mr Gordon, to conclude that the boost from IT has run its course.

As you can read in the piece, this seems like an extremely premature conclusion. Recent data are very difficult to parse given the gyrations of the economic crisis. Neither is productivity growth ever a smooth process; there were surges and lulls during the late 19th and early 20th centuries, as well, but the very long-run picture was one of strong growth. Meanwhile, there is also a considerable lag between discovery of a new invention and its deployment as a productivity boosting innovation in the real economy; the boom from the mid-1990s to the mid-2000s was driven by progress in computing across the 1980s and 1990s. Today's machines, smartphones, and web have only begun to influence the broader economy. And there is strong anecdotal evidence indicating that the pace of innovation may be rising; impressive advances in computing, medical technology, robotics, and so on seem to be popping up more frequently than at any time in recent memory.

The jury must remain out until more data are in, but given available information a broad pessimism about the rich world's ability to think up new growth-boosting stuff seems unjustified.

That said, there are real outstanding questions about the nature of growth. Our piece gets into some of these issues. I'm not sure that modern society is as flexible in the face of revolutionary new technologies as was once the case. Driverless cars may be more difficult to accommodate, for infrastructural and regulatory reasons, than human-directed cars were a century ago. A much larger share of modern economic activity is made up of sectors, like health care, education, and government, that are relatively unresponsive to market forces. That could slow the spread of new productivity boosting technologies and business models across the economy as a whole.

I am pretty sanguine on these issues, however. To be really nerdy about it, I suspect that societal rigidity is endogenous to the pace of underlying technological growth. That is, slow progress breeds institutional sclerosis which may erode pretty quickly in the face of impressive and valuable new technologies. To take a simple example: if it really seems like driverless cars may save thousands of lives, millions of hours of wasted time, and billions of dollars, then the regulatory climate will prove less a hurdle than now seems likely.

The much thornier issue is whether a new burst of innovative growth will affect the wages and welfare of a typical worker in the way that the industrial revolution did. That's a very tough but very important question. 

There is no clear way to understand how technology affects median wages. Overall productivity and output will probably rise and may rise quite quickly. The scarce factors in the economy will then be the ones that are able to capture most of the resulting surplus. But which will be the scarce factors? Will it be owners of capital? Highly skilled workers or managerial talent? Owners of land in innovative cities?

The answer isn't simply a matter of technology. If growth is skills biased, then the supply of skills matters, which means that education and immigration policy are hugely important. If the extent of the market matters, and it does, then zoning rules, trade deals, and infrastructure investment are also important. As is the structure of the welfare state. If income equality continues to grow, the safety net could mean the difference in broad hardship and a new age of middle-class health, complete with rising pay and (or) shrinking workweeks. The world's great discoveries made the industrial revolution possible, but its welfare effects were strongly driven by state investments in infrastructure and education, improvements in macroeconomic policy, and the development of the modern welfare state.

And it's worth pointing out that some of the lucky, positive interactions between innovation and state policy were more or less accidental. It's not clear that we know precisely how to tailor policy and public investment now to maximise the welfare return of new technologies. (More and better investment in education seems a no brainer, but what about a major public investment in broadband? Hard to say.)

The unknown is the unknown. So while I'm optimistic about the prospects for innovation and economic growth, it's worth acknowledging that there's no telling how it all will end up until well after the fact.