To Explain the World by Steven Weinberg

Write about what you know. Write from your experience. Those two mandates are easily given to anyone who wants to write for a living. They apply to fiction and non-fiction. The rules were too easily ignored by Nobel laureate Steven Weinberg 

To Explain the World: The Discovery of Modern Science by Steven Weinberg (HarperCollins, 2015) presents—and I believe, proves—the thesis that science was not invented, but exists independent of the observer. In my words, not his, science is as objective as helium or an elephant: it is what it is for any observer. Although science is a very human pursuit, it would be the same for a practitioner in another galaxy. Dr. Weinberg asserts that modern science had to be discovered. It was not practiced in Ancient Greece, the Islamic Middle East, China, or Medieval Europe. The essence of modern science is the controlled (and therefore “unnatural”) experiment. 

To Explain the World is Dr. Weinberg’s personal review of Western intellectual history. I had several classes in it at university and it remained a pursuit integral to my own lifestyles. So, I had a firm foundation from which to take issue with many of his assertions. However, someone who comes to this book without prior learning will be given some clichés, now abandoned by historians at his level. Some claims are just plain false, though they come well-attributed by second-hand sources. For one thing, Steven Weinberg admits to not reading Greek, though he seems to know Latin well. So, the review of the natural philosophy of the ancient Greeks is based on the usual English translations. 

 

Weinberg knows science. His Nobel prize attests to that, though his degrees and research seem to be enough. Where he is weak is in history. This is his view, his interpretation. I accept the thesis. I am forced to reject some of the evidence. Also, oddly enough, he is less than perfectly clear on just what science is. Very much like a university textbook, he just assumes that you know the scientific method, though he never defines it and certainly does not investigate how its procedures were integrated into the modern practice we know. (My overview of "The Scientific Method" is here.)

  

In science, we might accept authority, but we never take anything on faith, and Prof. Weinberg is a teacher. So, this book delivers a special value in the Technical Notes at the end. There, you will find proofs and elaborations of the mathematics, astronomy, and physics supporting the narratives.

Where he goes astray is in the history. The book is replete with small errors of fact. “If Archimedes by his measurement of specific gravity had identified a gilded lead crown as being made of solid gold, he would have become unpopular in Syracuse.” (page 41) The crown was not gilded. If that were the suspicion, just cutting into it would have revealed the lead core. We know hundreds if not thousands of just such false coins from the ancient world. No, the crown was an alloy of silver and gold. The jeweler removed some gold and replaced it with silver. Visibly, the crown looked like pure gold. Only the test of specific gravity betrayed the culprit. It seemed to me to be the salient point, not to be missed or confused by a practicing physicist. Moreover, the book was read through by several others, including historian of astronomy, Owen Gingerich. Someone should have caught it.

Weinberg accepts the common narrative that the ancient Greeks, especially the Athenians, did not value labor and therefore did not perform experiments. Weinberg quotes Shakespeare’s Midsummer Night’s Dream: “Hard-handed men, who work now in Athens, and never yet labor’d with their minds.” (page 34) He could have looked closer to the source. “Now I observe that when we are met together in the assembly, and the matter in hand relates to building, the builders are summoned as advisers; when the question is one of shipbuilding, then the ship-wrights; and the like of other arts which they think capable of being taught and learned. And if some person offers to give them advice who is not supposed by them to have any skill in the art, even though he be good-looking, and rich, and noble, they will not listen to him, but laugh and hoot at him, until either he is clamoured down and retires of himself; or if he persist, he is dragged away or put out by the constables at the command of the prytanes." -- Plato's Dialogues, "Protagoras," translated by Benjamin Jowett.

Weinberg notes that more investigations that we recognize as science were carried out in the Hellenistic era, than in the classical. That is true. Supporting his claim he offers the work of Philo of Byzantium (280-220 BCE), Mechanike Syntaxis, in which an experiment in hydrostatics demonstrates that air is a substance. However, readers or viewers of Carl Sagan’s Cosmos learned that in the classical era Empedocles of Akragas explained the action of a kitchen tool, the water-thief (clepsydra), 200 years earlier. 

Taking common easy claims in lieu of research into ancient history, Weinberg says that the Greeks named the planets Hermes, Aphrodite, Ares, Zeus, and Cronos. (page 77) .They did not. Very many sources, including the works of Otto Neugebauer, correctly identify the ancient Greek names Stilbon, Eosphoros/Hesperos, Pyroeis, Phaetho, and Phainon: Sparkler, Dawn-bringer/Evening, Fiery, Shining, and Blazing. Giving them names analogous to the Roman gods happened much later. Note, also, relevant to ancient astronomy, that the morning star and evening star were only correctly identified much later (by the time of Claudius Ptolemy) and properly identified with the planets Venus and Mercury depending on their relative positions. 

Similar errors mar the history of science in the European Middle Ages. At the start of Chapter 10 Medieval Europe, the seven liberal arts are listed as “grammar, logic, rhetoric, geography, arithmetic, astronomy, and music.” (page 124). Later, geometry is correctly placed among them to replace geography. Even as Weinberg probably made the mistake in his manuscript—an easy enough mistake if you are writing off the top of your head—someone should have caught it. 

 

This was a library book. A previous patron penciled very neat corrections to the errors in Greek and Latin. Among the half dozen or so, Philo's work was rendered as Mechanice syntaxism.

 

Weinberg refers to “… Newton’s own commitment to Unitarian Christianity…” (page 245) In point of fact, Unitarianism was anathema to the Anglican Church, and Newton perjured himself to get and keep his job at Cambridge when he swore to the Anglican confession and Trinitarianism. It is not a moot point. Also, though he cites it as a primary source, Weinberg seems to know Newton’s Principia only second hand. He cites Richard S. Westfall’s Never at Rest: A Biography of Isaac Newton (Cambridge 1980) and Chandrasekhar’s Common Reader edition of the Principia. Granted, it is difficult because we do not know geometry at the depth and breadth of Newton's time. We replaced it all with algebra and calculus. (Weinberg makes that point, also.) Even Richard Feynman failed to be able to independently recreate Newton's proof of Kepler's Third Law. (On the blog here.)

 

At worst, Weinberg’s narratives are as bad as Neil de Grasse Tyson’s. For example, telling of how Galileo rolled marbles off a table to record their path in freefall, Weinberg claims that “… the trajectory is a parabola.” (page 194) It is not. It is an ellipse. We allow college freshmen to assume that the Earth is flat and that gravity vectors point down parallel to each other and perpendicular to the ground. The math is easier and the approximation is close enough. 

The Wonders of Physics: an Introduction to the Physical World 
by Irving Adler  ( Illus. by Cornelius De Witt);
New York: Golden Press [1966].

However, as Weinberg says later: “Halley asked Newton what would be the actual shape of the orbit of a body moving under the influence of a force that decreases with the inverse square of the distance. Newton answered that the orbit would be an ellipse, and promised to send a proof.” (231) Again, this is not exactly true. The path is a conic section—circle, ellipse, parabola, hyperbola, line—depending on the tangential velocity of the object relative to the central force of the ponderable body at the focus. That eccentricity defines the shape of the curve. When you toss a baseball, the path is the same as it would be if you were 13,000 km from an extremely small object with the same mass as the Earth. Throw it faster and faster again and the path becomes a parabola, and then a hyperbola. Impel it extremely fast along any vector except directly at the center of mass and it will zoom off in a straight line, never to return.

 
Basically, Weinberg’s personal views aside, his editors at HarperCollins failed him. That being so, the thesis stands proved as asserted. However insightful were Democritus or Walter de Merton in teasing out the truths of motion in particular and the physical world in general, their work was not science. Science was a modern discovery. Consequential to that discovery was understanding the distinction between description and explanation. Unfortunately, Weinberg does not say more on that point, even though it is in the title of the book.

 

It is a whole lot easier to criticize than to create. In Fahrenheit 451, in explaining why he is attracted to reading, the fireman Montag says that inside each book is a man. This book was interesting and informative not because of the traps hidden by the putative histories, but for the opportunity to spend time with Steven Weinberg and to understand his view of his practice of his science.

 

PREVIOUSLY ON NECESSARY FACTS

 

Copernicus on the Revolution of Heavenly Bodies 

De Magnete by William Gilbert 

Feynman’s Rainbow by Leonard Mlodinow 

Harriman’s Logical Leap Almost Makes It