Steven Weinberg has a story to tell in “To Explain the World: The Discovery of Modern Science,” and it’s not at all as unapproachable as you might think. The winner of the Nobel Prize for physics in 1979, Weinberg writes with clarity and wit about the story of science, which he sees as “one of the most interesting in human history.”
The new book grew out of notes that Weinberg made for teaching a course on the history of science at the University of Texas, where he holds the Josey Regental Chair. “Again and again in preparing the lectures for my course I have been impressed with how different the work of science in past centuries was from the science of my own times,” Weinberg writes. “And that evolved into the present volume, which is primarily concerned with ‘how we came to learn how to learn about the world.’”
Besides his status as a Nobel Prize winner, Weinberg has a well-earned reputation as a writer. He’s a longtime contributor to the New York Review of Books, and his other works include “The First Three Minutes,” “Dreams of a Final Theory,” “Facing Up” and “Lake Views.”
In academia, as you’re probably aware, there are usually different schools of thought, even within a particular discipline, and Weinberg is a leader in what is called “reductionism,” which seeks to explain a wide range of scientific principles in terms of simpler, more universal ones. The New York Times famously called him perhaps the world’s most authoritative proponent of the idea that physics is hurtling toward a “final theory” — a complete explanation of nature’s particles and forces that will endure as the bedrock of all science for evermore.
“Whatever you think of Weinberg’s approach,” wrote longtime science journalist Tom Siegfried in a review for Science News, “his account of science’s history is incisive, precise and thoroughly informed. It’s not a full history of the efforts to understand nature that were made in the centuries before Copernicus shattered Aristotelianism, but a succinct and authoritative summary of the key steps in the path to modern methods and knowledge.”
Although Weinberg sees imperfections in modern science, he says that the scientific technique is “sufficiently well tuned to nature so that it works — it is a practice that allows us to learn reliable things about the world. In this sense, it was a technique that was waiting for people to discover it.”
That discovery didn’t come easy, as Weinberg makes clear in his early chapters. In particular, he debunks what he considers to be exaggerated claims of accomplishment by Plato, Aristotle and Descartes. He says he isn’t trying to “accuse some past natural philosophers of stupidity.”
“Rather, by showing how far these very intelligent individuals were from our present conception of science, I want to show how difficult was the discovery of modern science, how far from obvious are its practices and standards.”
The emphasis in “To Explain the World” is on physics and astronomy. “It was in physics, especially as applied to astronomy, that science first took a modern form,” he says.
“In telling this story, I will be coming close to the dangerous ground that is most carefully avoided by contemporary historians, of judging the past by the standards of the present,” Weinberg says. “This is an irreverent history; I am not unwilling to criticize the methods and theories of the past from a modern viewpoint.”
The first sections focus on Greek physics and astronomy, discussing the flawed but triumphant achievement of Hellenistic science in measuring the sizes of the sun, moon and earth, and the distances to the sun and moon. He limits his praise, however, noting that it never occurred to the Greeks that their measurements might need to account for the probability of error.
In discussing the Middle Ages, he doesn’t consider the period after the fall of Rome to be “an intellectual desert.” Instead, what he discusses is the continuation of ancient debates during the Middle Ages on how science fits in — or doesn’t fit in — with philosophy, mathematics and religion.
The beginnings of the scientific revolution dominate the middle of the book, and Weinberg notes that some historians even criticize the notion of a scientific revolution and see it more as a continuation of scientific progress in the Middle Ages. But Weinberg states categorically: “There was a scientific revolution, and the rest of this book is about it.”
Weinberg’s reasoning can be fascinating — and eye-opening. For instance, in discussing astronomy, he notes that we generally suppose that “the expanding universe, the enormous cloud of galaxies that we observe rushing apart uniformly in all directions, is the whole universe. We think that the constants of nature we measure … will eventually all be deduced from the yet unknown fundamental laws of nature. But it may be that what we call the expanding universe is just a small part of a much larger ‘multiverse,’ containing many expanding parts like the one we observe, and that the constants of nature take different values in different parts of the multiverse.”
In his typically droll tone, Weinberg says that some “distinguished physicists deplore the idea of a multiverse, because they cannot reconcile themselves to the possibility that there are constants of nature that can never be calculated.” Then he adds: “Whatever the final laws of nature may be, there is no reason to suppose that they are designed to make physicists happy.”
Weinberg’s humor also is on full display in his discussion of the scientific contributions of Descartes. Weinberg begins to list all of the things that Descartes got wrong, including that the pineal gland “is the seat of a soul responsible for human consciousness.” Descartes was also “wrong in saying that the speed of a freely falling body is proportional to the distance fallen.”
Then Weinberg concludes with this zinger, dealing with Descartes’ idea that animals are merely mechanical automatons. “On the basis of observation of several lovable pet cats, I am convinced that Descartes was also wrong in saying that animals are machines without true consciousness.”
Weinberg sees the climax of the scientific revolution as coming with Isaac Newton in the 17th century, who “tied up strands of physics, astronomy, and mathematics whose relations had perplexed philosophers since Plato.”
Newton’s “Principia,” Weinberg says, “established the laws of motion and the principle of universal gravitation, but that underestimates its importance. Newton had given to the future a model of what a physical theory can be: a set of simple mathematical principles that precisely govern a vast range of different phenomena.”
Weinberg closes his narrative on this hopeful note: “This is a grand story — how celestial and terrestrial physics were unified by Newton, how a unified theory of electricity and magnetism was developed that turned out to explain light, how the quantum theory of electromagnetism was expanded to include the weak and strong nuclear forces, and how chemistry and even biology were brought into a unified though incomplete view of nature based on physics. It is toward a more fundamental physical theory that the wide-ranging scientific principles we discover have been, and are being, reduced.”
Weinberg’s book can be dense at times, but that shouldn’t scare you away. He’s one of our greatest defenders of scientific thought, and his wit is a welcome salve in this authoritative history.
To Explain the World