It’s a great pity that Steven Weinberg’s new book on the history of science, To Explain the World: The Discovery of Modern Science, is coming out too late to be included in my own book, in which I discuss the apologists’ contention that science was an outgrowth of medieval Christianity. Weinberg’s book, whose existence I discovered through a Facebook post by physicist Sean Carroll, will be released Feb. 17 by HarperCollins.
You probably know that Weinberg is a Nobel Laureate, having received the Big Prize in 1979 along with Sheldon Glashow and Abdus Salam for unifying the weak and electromagnetic forces—a step forward in physics’ drive to unify all four forces. And I knew he had a pretty deep knowledge of the history of science, for he’s written about it in his New York Review of Books articles. But I had no idea he was producing a book.
Intrigued, I wrote Steve asking if he had any more information for my readers, and specifically asked two things: how he came to write the book, and why he thought that modern science seemed to derive largely from Europe rather than elsewhere. I added that I had been reading a lot of apologists who asserted that science was the product of Christianity in the Middle Ages. Weinberg responded by sending me two excerpts from the book that, he thought, would answer my questions. These excerpts are not on the Amazon site, nor anywhere else I can find, but here they are:
I am a physicist, not a historian, but over the years I have increasingly become fascinated by the history of science. It is an extraordinary story, one of the most interesting in human history. It is also a story in which scientists like myself have a personal stake. Today’s research can be aided and illuminated by a knowledge of its past, and for some scientists knowledge of the history of science helps to motivate present work. We hope that our research may turn out to be a part, however small, of the grand historical tradition of natural science.
Where my own past writing has touched on history, it has been mostly the modern history of physics and astronomy, roughly from the late nineteenth century to the present. Although in this era we have learned many new things, the goals and standards of physical science have not materially changed. If physicists of 1900 were somehow taught today’s Standard Model of cosmology or of elementary particle physics, they would have found much to amaze them, but the idea of seeking mathematically-formulated and experimentally-validated impersonal principles that explain a wide variety of phenomena would have seemed quite familiar.
A while ago I decided that I needed to dig deeper, to learn more about an earlier era in the history of science, when the goals and standards of science had not yet taken their present shape. As is natural for an academic, when I want to learn about something, I volunteer to teach a course on the subject. Over the past decade I have from time to time taught undergraduate courses on the history of physics and astronomy at the University of Texas, to students who had no special background in science, mathematics, or history. This book grew out of the lecture notes for those courses.
But as this book has developed, perhaps I have been able to offer something that goes a little beyond a simple narrative: It is the perspective of a modern working scientist on the science of the past. I have taken this opportunity to explain my views about the nature of physical science, and about its continued tangled relations with religion, technology, philosophy, mathematics, and aesthetics.
Before history there was science, of a sort. At any moment nature presents us with a variety of puzzling phenomena: fire, thunderstorms, plagues, planetary motion, light, tides, and so on. Observation of the world led to useful generalizations: fires are hot, thunder presages rain; tides are highest when the Moon is full or new; etc. These became part of the common sense of mankind. But here and there, some people wanted more than just a collection of facts. They wanted to explain the world.
It was not easy. It is not only that our predecessors did not know what we know about the world — more important, they did not have anything like our ideas of what there was to know about the world, and how to learn it. 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. As the much quoted lines of a novel of L.P. Hartley put it, “The past is a foreign country; they do things differently there.” I hope that in this book I have been able to give the reader not only an idea of what happened in the history of the exact sciences, but also a sense of how hard it has all been.
So this book is not solely about how we came to learn various things about the world. That is naturally a concern of any history of science. My focus in this book is a little different — it is how we came to learn how to learn about the world.
I am not unaware that the word “explain” in the title of this book raises problems for philosophers of science. They have pointed out the difficulty in giving a precise distinction between explanation and description. (I will have a little to say about this in Chapter 8.) But this is a work on the history rather than the philosophy of science. By explanation I mean something imprecise, the same as is meant in ordinary life, when we try to explain why a horse has won a race or why an airplane has crashed.
The word “discovery” in the subtitle is also problematic. I had thought of using The Invention of Modern Science as a subtitle. After all, science could hardly exist without human beings to practice it. I chose “Discovery” instead of “Invention” to suggest that science is the way it is not so much because of various adventitious historic acts of invention, but because of the way nature is. With all its imperfections, modern science is a technique that 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 is a technique that was waiting for people to discover it.
Thus one can talk about the discovery of science in the way that a historian can talk about the discovery of agriculture. With all its variety and imperfections, agriculture is the way it is because its practices are sufficiently well tuned to the realities of biology so that it works — it allows us to grow food. I also wanted with this title to distance myself from the few remaining social constructivists: those sociologists, philosophers, and historians who try to explain not only the process but even the results of science as products of a particular cultural milieu.
The science in the subtitle of this book is modern science, a technique that goes beyond casual observation, and is now practiced throughout the world by professionals who call themselves scientists. Among the branches of science, this book will emphasize physics and astronomy. It was in physics, especially as applied to astronomy, that science first took a modern form. Of course there are limits to the extent to which sciences like biology, whose principles depend so much on historical accidents, can or should be modeled on physics. Nevertheless, there is a sense in which the development of scientific biology as well as chemistry in the nineteenth and twentieth centuries followed the model of the revolution in physics of the seventeenth century.
Science is now international, perhaps the most international aspect of our civilization, but the discovery of modern science happened in what may loosely be called the West. Modern science learned its methods from research done in Europe in the scientific revolution, which in turn evolved from work done in Europe and in Arab countries in the Middle Ages, and ultimately from the precocious science of the Greeks. The West borrowed much scientific knowledge from elsewhere — geometry from Egypt, astronomical data from Babylon, the techniques of arithmetic from Babylon and India, the magnetic compass from China, and so on — but as far as I know it did not import the methods of modern science. So this book will emphasize the West (including medieval Islam) in just the way that was deplored by Oswald Spengler and Arnold Toynbee: I will have little to say about science outside the West, and nothing at all to say about the interesting but entirely isolated progress made in pre-Columbian America.
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. This is an irreverent history; I am not unwilling to criticize the methods and theories of the past from a modern viewpoint. I have even taken some pleasure in uncovering a few errors made by scientific heroes that I have not seen mentioned by historians.
A historian who devotes years to study the works of some Great Man of the past may come to exaggerate what their hero has accomplished. I have seen this in particular in works on Plato, Aristotle, Avicenna, Grosseteste and Descartes. But it is not my purpose here 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. This also serves as a warning, that science may not yet be in its final form. At several points in this book I suggest that, as great as is the progress that has been made in the methods of science, we may today be repeating some of the errors of the past.
Some historians of science make a shibboleth of not referring to present scientific knowledge in studying the science of the past. I will instead make a point of using present knowledge to clarify past science. For instance, though it might be an interesting intellectual exercise to try to understand how the Hellenistic astronomers Apollonius and Hipparchus developed the theory that the planets go around the Earth on looping epicyclic orbits by using only the data that was available to them, this is impossible, for much of the data they used is lost. But we do know that in ancient times the Earth and planets went around the Sun on nearly circular orbits, just as they do today, and by using this knowledge we will be able to understand how the data available to ancient astronomers could have suggested to them their theory of epicycles. In any case, how can anyone today, reading about ancient astronomy, forget our present knowledge of what actually goes around what in the solar system?
For readers who want to understand in greater detail how the work of past scientists fits in with what actually exists in nature, there are “technical notes” at the back of the book. It is not necessary to read these notes to follow the book’s main text, but some readers may learn a few odd bits of physics and astronomy from these notes, as I did in preparing them.
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Science is not now what it was at its start. Its results are impersonal. Inspiration and aesthetic judgment are important in the development of scientific theories, but the verification of these theories relies finally on impartial experimental tests of their predictions. Though mathematics is used in the formulation of physical theories and in working out their consequences, science is not a branch of mathematics, and scientific theories cannot be deduced by purely mathematical reasoning. Science and technology benefit each other, but at its most fundamental level science is not undertaken for any practical reason. Though science has nothing to say one way or the other about the existence of God or the afterlife, its goal is to find explanations of natural phenomena that are purely naturalistic. Science is cumulative; each new theory incorporates successful earlier theories as approximations, and even explains why these approximations work, when they do work.
None of this was obvious to the scientists of the ancient world or the Middle Ages, and it was learned only with great difficulty in the scientific revolution of the sixteenth and seventeenth centuries. Nothing like modern science was a goal from the beginning. So how then did we get to the scientific revolution, and beyond it to where we are now? That is what we must try to learn as we explore the discovery of modern science.
The book is only $21 in hardcover, or $16 on Kindle. As you can see, Weinberg is a lucid and entertaining writer, and I’d recommend this book without having seen it. In the meantime, read his article “A designer universe?” from the 1999 New York Review of Books, which takes up the question of whether the Universe gives evidence for a god. Since Weinberg is an uncompromising atheist, you can guess the answer.