Science’s Path From Myth to Multiverse
In his latest book, the Nobel Prize winner Steven Weinberg explores how science made the modern world, and where it might take us from here.
We can think of the history of physics as an attempt to unify the world around us: Gradually, over many centuries, we’ve come to see that seemingly unrelated phenomena are intimately connected. The physicist Steven Weinberg of the University of Texas, Austin, received his Nobel Prize in 1979 for a major breakthrough in that quest — showing how electromagnetism and the weak nuclear force are manifestations of the same underlying theory (he shared the prize with Abdus Salam and Sheldon Glashow). That work became a cornerstone of the Standard Model of particle physics, which describes how the fundamental building blocks of the universe come together to create the world we see....MORE
In his new book To Explain the World: The Discovery of Modern Science, Weinberg examines how modern science was born. By tracing the development of what we now call the “scientific method” — an approach, developed over centuries, that emphasizes experiments and observations rather than reasoning from first principles — he makes the argument that science, unlike other ways of interpreting the world around us, can offer true progress. Through science, our understanding of the world improves over time, building on what has come before. Mistakes can happen, but are eventually corrected. Weinberg spoke with Quanta Magazine about the past and future of physics, the role of philosophy within science, and the startling possibility that the universe we see around us is a tiny sliver of a much larger multiverse. An edited and condensed version of the interview follows.
QUANTA MAGAZINE: As a physicist, how is your perspective on the history of science different from that of a historian?
STEVEN WEINBERG: One difference, of course, is that they know more than I do — at least, in their particular field of specialization. Real historians have a much better grasp of the original sources than I could possibly have. If they’re historians of the ancient world, they’ll be experts in Greek and Latin, which I’m not even remotely knowledgeable about.
But there’s also a difference in attitude. Many historians are strongly opposed to the so-called “Whig interpretation” of history, in which you look at the past and try to pick out the threads that lead to the present. They feel it’s much more important to get into the frame of mind of the people who lived at the time you’re writing about. And they have a point. But I would argue that, when it comes to the history of science, a Whig interpretation is much more justifiable. The reason is that science, unlike, say, politics or religion, is a cumulative branch of knowledge. You can say, not merely as a matter of taste, but with sober judgment, that Newton knew more about the world than Aristotle did, and Einstein knew more than Newton did. There really has been progress. And to trace that progress, it makes sense to look at the science of the past and try to pick out modes of thought that either led to progress, or impeded progress.
Why did you focus on the history of physics and astronomy?
Well, that’s what I know about; that’s where I have some competence. But there’s another reason: It’s in physics and astronomy that science first became “modern.” Actually, it’s physics as applied to astronomy. Newton gave us the modern approach to physics in the late 17th century. Other branches of science became modern only more recently: chemistry in the early 19th century; biology in the mid-19th century, or perhaps the early 20th century. So if you want to understand the discovery of modern science — which is the subtitle of my book — that discovery was made in the context of physics, especially as applied to astronomy.
Theoretical physics is often seen as a quest for unification — we think of Newton, unifying terrestrial and celestial physics, or James Clerk Maxwell, unifying electricity, magnetism, and light. And of course your own work. Where does this quest for unification stand today?
It hasn’t advanced very much, except for the fact that the theories we speculated about in the 1960s have been confirmed by observation. In the theory I developed in 1967 — Abdus Salam developed essentially the same theory, independently, in 1968 — a symmetry-breaking field played a fundamental role, manifest in a particle called the Higgs boson, whose properties we predicted, except for its mass. Now, thanks to experiments performed at CERN, the Higgs has been verified. So we’re on much more solid ground. But we haven’t gone any further. There have been enormous efforts to take further steps, especially in the context of string theory. String theory would unify all of the forces — the strong and weak nuclear forces, and the electromagnetic force, together with gravity. String theory has provided some deep mathematical ideas about how that might work. But we’re far from being able to verify the theory — much further than we were from verifying the electroweak theory 40 years ago.
The Large Hadron Collider (LHC) is scheduled to start up again this year, with twice the power it had during its initial run. What do you hope it’ll find — I’m not sure if “hope” is the right word — when it’s turned on?
