Share
Babbage from The Economist
Babbage: The science that built the AI revolution—part two
•
How do machines learn? Learning is fundamental to artificial intelligence. It’s how computers can recognise speech or identify objects in images. But how can networks of artificial neurons be deployed to find patterns in data, and what is the mathematics that makes it all possible?
This is the second episode in a four-part series on the evolution of modern generative AI. What were the scientific and technological developments that took the very first, clunky artificial neurons and ended up with the astonishingly powerful large language models that power apps such as ChatGPT?
Host: Alok Jha, The Economist’s science and technology editor. Contributors: Pulkit Agrawal and Gabe Margolis of MIT; Daniel Glaser, a neuroscientist at London’s Institute of Philosophy; Melanie Mitchell of the Santa Fe Institute; Anil Ananthaswamy, author of “Why Machines Learn”.
On Thursday April 4th, we’re hosting a live event where we’ll answer as many of your questions on AI as possible, following this Babbage series. If you’re a subscriber, you can submit your question and find out more at economist.com/aievent.
Get a world of insights for 50% off—subscribe to Economist Podcasts+
If you’re already a subscriber to The Economist, you’ll have full access to all our shows as part of your subscription. For more information about how to access Economist Podcasts+, please visit our FAQs page or watch our video explaining how to link your account.
More episodes
View all episodes
Protecting the jungle: on the road with Madagascar’s seed hunters
43:24|Between 2001 and 2024, a quarter of Madagascar’s native rainforest has vanished. At this rate of destruction, those ecosystems will be entirely wiped out by the end of the century. Could collecting and preserving the seeds of the endangered plants help repair the country’s ancient forests?Host: Alok Jha, The Economist’s science and technology editor. Guests: The Economist’s Ainslie Johnstone; Henintsoa Razanajatovo and Nomentsoa Randriamamonj of Kew Madagascar; Sharon Balding and Charlotte Lusty of Kew’s Millennium Seed Bank at Wakehurst.Transcripts of our podcasts are available via economist.com/podcasts.Listen to what matters most, from global politics and business to science and technology—subscribe to Economist Podcasts+.For more information about how to access Economist Podcasts+, please visit our FAQs page or watch our video explaining how to link your account.
Neil Shubin: defender of American science
36:28|Two decades ago, Neil Shubin discovered a fish-like fossil which transformed scientists’ understanding of how animals transitioned out of the sea. In this episode, Prof Shubin tells us about hunting for fossils at Earth’s extremes and how he is gearing up for another big challenge: taking the reins of America’s National Academy of Sciences. In his telling, American science is in a “dark age”. Why, then, is he so optimistic?Host: Alok Jha, The Economist’s science and technology editor. Guest: Professor Neil Shubin of the University of Chicago and the author of “Ends of the Earth”.Transcripts of our podcasts are available via economist.com/podcasts.Listen to what matters most, from global politics and business to science and technology—subscribe to Economist Podcasts+.For more information about how to access Economist Podcasts+, please visit our FAQs page or watch our video explaining how to link your account.
Nitazenes: the rise of a dangerous new opioid
36:10|A new class of synthetic opioids is sweeping through illicit drug markets all over the world. Nitazenes can be up to 25 times more potent than fentanyl—and hundreds of times stronger than heroin. How could restrictions on other drugs have fuelled the spread of these dangerous new opioids, and what should governments do about it?Host: Alok Jha, The Economist’s science and technology editor. Guests: The Economist’s Emilie Steinmark; Phoenix Kellye of Rebel Harm Reduction; George Eze of the University of Sierra Leone Teaching Hospitals Complex. Thanks also to The Economist’s Ore Ogunbiyi. Transcripts of our podcasts are available via economist.com/podcasts.Listen to what matters most, from global politics and business to science and technology—subscribe to Economist Podcasts+.For more information about how to access Economist Podcasts+, please visit our FAQs page or watch our video explaining how to link your account.
Nobel prizes: the 2025 science awards
36:58|Since 1901, the Nobel prizes have been the pinnacle of scientific achievement. This week, nine more scientists joined the ranks of Albert Einstein and Marie Curie, as they were recognised for their work in immunology, quantum computing and inventing a new class of materials. Who are the scientists who earned those coveted phone calls from Stockholm?Host: Alok Jha, The Economist’s science and technology editor. Guests: The Economist’s Natasha Loder, Geoff Carr and Tim Cross.Transcripts of our podcasts are available via economist.com/podcasts.Listen to what matters most, from global politics and business to science and technology—subscribe to Economist Podcasts+.For more information about how to access Economist Podcasts+, please visit our FAQs page or watch our video explaining how to link your account.
John Pendry: the physics of invisibility
44:44|How do you make an object invisible? Professor Sir John Pendry worked out that it involves guiding and bending light in precise ways by changing the structure of the material it is travelling through. His subsequent work on the interactions between light and matter has led to a new class of materials, known as “metamaterials”, which enable seemingly impossible things to happen. In this episode, he tells us how they work and their applications in everything from 5G technology to simulating the conditions around black holes.Host: Alok Jha, The Economist’s science and technology editor. Guest: Professor Sir John Pendry of Imperial College London.Transcripts of our podcasts are available via economist.com/podcasts.Listen to what matters most, from global politics and business to science and technology—subscribe to Economist Podcasts+.For more information about how to access Economist Podcasts+, please visit our FAQs page or watch our video explaining how to link your account.
Critical chemistry: what makes rare earths so special?
39:33|China sowed panic earlier this year when it restricted exports of rare-earth elements. The country has a near-monopoly on the critical minerals, which are used in everything from fighter jets to fibre optics. How does the unique chemical structure of rare earths make them so vital to so many different technologies—and how can western industry reduce its dependence on China for their supply?Host: Alok Jha, The Economist’s science and technology editor. Guests: Andrea Sella of University College London; and The Economist’s Tim Cross and Anjani Trivedi. Transcripts of our podcasts are available via economist.com/podcasts.Listen to what matters most, from global politics and business to science and technology—subscribe to Economist Podcasts+.For more information about how to access Economist Podcasts+, please visit our FAQs page or watch our video explaining how to link your account.
Life on Mars: how promising are the latest findings?
38:39|Scientists at NASA recently announced that they had found “the clearest sign of life” that has ever been discovered on Mars. The “potential biosignature” of ancient microbial life was found in a Martian rock sample. But to find out if it really is a sign of life, the sample needs to be brought back to Earth for further study—a task far more complicated than you might expect.Host: Alok Jha, The Economist’s science and technology editor. Guests: Katie Stack Morgan of NASA’s Jet Propulsion Laboratory; Sanjeev Gupta of Imperial College London; and The Economist’s Oliver Morton.Transcripts of our podcasts are available via economist.com/podcasts.Listen to what matters most, from global politics and business to science and technology—subscribe to Economist Podcasts+.For more information about how to access Economist Podcasts+, please visit our FAQs page or watch our video explaining how to link your account.
Well informed: how to get strong
28:26|Conventional wisdom has it that you need to move your body regularly to stay fit. But these days scientists argue that you should probably trade in the treadmill for some dumbbells. Strength training is having a moment. In this episode, part of our “Well informed” series on wellness trends, we take an evidence-based look at three popular routes to maximising your strength: weightlifting, eating protein, and taking creatine supplements. The world of fitness is filled with powders and supplements that claim bold things, but what’s the real secret to becoming—and staying—strong?Host: Alok Jha, The Economist’s science and technology editor. Contributors: The Economist’s Tim Cross, Richard Kreider of Texas A&M University.Transcripts of our podcasts are available via economist.com/podcasts.Listen to what matters most, from global politics and business to science and technology—subscribe to Economist Podcasts+.For more information about how to access Economist Podcasts+, please visit our FAQs page or watch our video explaining how to link your account.
JUNO: the hunt for the universe’s most elusive particles
40:29|Neutrinos are elementary particles that are extremely light and rarely interact with anything else. Mostly, they pass invisibly through the universe—hundreds of trillions of neutrinos will have passed through your body as you read this. For physicists, though, these ghostly particles present a big problem. The prevailing theory of particle physics, the Standard Model, predicts that neutrinos should have no mass—but this is not what physicists observe in the real world. Now, scientists at JUNO, an enormous new lab in China, have started to hunt for the elusive particles and, in doing so, they hope to solve this giant conundrum in fundamental physics.Host: Alok Jha, The Economist’s science and technology editor, with Emilie Steinmark, The Economist’s science correspondent. Contributors: Juan Pedro Ochoa-Ricoux of the University of California, Irvine; Wang Yifang and Yuekun Heng of the Chinese Academy of Sciences.Transcripts of our podcasts are available via economist.com/podcasts.Listen to what matters most, from global politics and business to science and technology—subscribe to Economist Podcasts+.For more information about how to access Economist Podcasts+, please visit our FAQs page or watch our video explaining how to link your account.