Have scientific breakthroughs declined?

2023 had barely begun when scientists got some jolting news. On 4 January, a paper appeared in Nature claiming that disruptive scientific findings have been waning since 1945. An accompanying graph showed all fields on a steep downhill slide. 

Scientists took this as an affront. The New York Times interpreted the study to mean that scientists aren't producing as many "real breakthroughs" or "intellectual leaps" or "pioneering discoveries." That seems paradoxical when each year brings a new crop of exciting findings. 

In the 12 months following that paper, scientists have listened to the close encounters between supermassive black holes, demonstrated the power of new weight loss drugs and brought to market life-changing gene therapies for sickle cell disease.

What the authors of the January paper measured was a changing pattern in the way papers were cited. They created an index of disruptiveness that measured how much a finding marked a break with the past. 

A more disruptive paper would be cited by many future papers while previous papers in the same area would be cited less — presumably because they were rendered obsolete. This pattern, they found, has been on a decades-long decline.

One of the authors, Russell Funk of the Carlson School of Management at the University of Minnesota, said they wanted to measure how new findings shifted attention away from old ways of doing things. "Science definitely benefits from a cumulative work and studies that come along and refine our existing ideas. But it also benefits from being shaken up every now and then," he said. 

We're seeing fewer shake-ups now. Funk said he thinks it's related to funding agents taking too few risks. But others say it may only reflect changes in the way scientists cite each other's work. Scientists I talked to said researchers cite papers for many reasons — including as way to ingratiate themselves with colleagues, mentors or advisers. Papers on techniques get a disproportionate number of citations, as do review articles because they're easier to cite than going back to the original discoveries. 

Citations in papers are "noisy data" Funk admitted, but there's a lot of it — millions of papers — and such data can reveal interesting trends. He agreed, though, that people shouldn't conflate disruption with importance. He gave the example of the LIGO (the Laser Interferometer Gravitational-Wave Observatory), which made a big splash in 2016 by detecting gravitational waves, long ago predicted by Einstein. By his definition it was not disruptive.

I was glad he brought up this project, which is operated by Caltech and MIT. Confirming Einstein was just the beginning – LIGO also opened up a new way of observing the universe, allowing scientists to detect collisions between invisible objects, like black holes and neutron stars. In some ways, I think it was too novel to be disruptive — it didn't displace earlier ways of doing something. There were no earlier ways of doing what it does. 

Biologist Gregory Petsko of Harvard Medical School said a better way to think about important science would be to consider some findings transformative — opening new avenues without closing off the old — though he agreed that the funding agents could get more disruption by taking more chances on long-shots.

He listed three findings he considers transformative. The first was PCR (polymerase chain reaction), which allowed scientists to amplify DNA and vastly improved their ability to decipher the information coded there. The second was the reprogramming of adult skin cells so they could act like embryonic stem cells. The third was Crispr, the technique for precisely editing the genetic information in DNA. These may or may not have put anyone out of business (as a "disruptive" discovery might have done) but they opened up vast new possibilities in basic science as well as medicine. 

The world does need more long-shot research, said George Church, professor of genetics at the Harvard-MIT Program in Health Sciences and Technology. "In fact, you should fail a million times a day, which is in contrast to the NASA motto, which is failure is not an option," he said. 

He strongly disagrees with the notion that scientific progress is declining. He co-wrote a rebuttal to the disruption paper for STAT, in which he argued disruption as measured by the study doesn't reflect what we should really want from science, which is knowledge that can help us live longer, better, healthier lives. 

Brian Uzzi, a professor at the Kellogg School of Management at Northwestern University, had another explanation for the changing pattern in scientific discovery. He said one thing that's changed steadily since 1945 is our cumulative knowledge. "Every year, more papers get published than the year before," he said. Now there are more than a million a year. That means, by necessity, students are trained more narrowly and are equipped to see smaller pieces of big problems. 

"That leads me to believe that it's not that science is becoming less disruptive, it is that science addresses problems in a brand-new way," he said. Revolutions are less likely to come down to individual papers; today they just happen on a more gradual scale as different researchers take on different pieces in a divide-and-conquer fashion. 

With the complexity of many of today's particle accelerators and space telescopes it's tempting to consider that most of the easy problems have been solved — an argument that's mocked whenever it's made. But one person not afraid to talk about it is science writer John Horgan, author of the 1996 book The End of Science. In a post for his website, he clarifies his view: 

There will be no more insights into nature as revolutionary as the theory of evolution, the double helix, quantum mechanics, relativity and the big bang. Why not? Because these profound discoveries are true. Put them together, and they form a map of reality that, like our maps of the Earth, is unlikely to undergo significant changes.

Horgan said since he wrote the book, he's changed his mind about some things — he thinks there might be room for a conceptual revolution in quantum mechanics. 

But even if it's true that the foundations of biology and physics are never going to be toppled, there's plenty of science yet to be done that most of us would consider profound — especially in the applied sciences. From curing disease to reducing global warming, there's no shortage of hard scientific problems crying out for solutions.

F D Flam is a Bloomberg Opinion columnist covering science

Disclaimer: This article first appeared on Bloomberg, and is published by special syndication arrangement.