Marcia Bartusiak is a professor in the MIT Graduate Program in Science Writing. She is the author of six books on the frontier and history of astrophysics. A new edition of her book on gravitational-wave astronomy, “Einstein’s Unfinished Symphony,” will be published this summer.

Mary Somerville would have been enthusiastically elected into the Royal Society of London in the 1800s — if women had been allowed to join. Celebrated in her time as an expert mathematician and thinker, she wrote a number of books on science, including “On the Connexion of the Physical Sciences,” published in 1834. Her aim, writes Peter Watson, “was to reveal the common bonds — the links, the convergence — between the physical sciences at a time when they were otherwise being carved up into separate disciplines.” She showed how dynamics, statics, hydrodynamics, optics and electricity could be placed under one roof of study. In fact, the term “scientist” was first introduced in a review of Somerville’s book to describe the members of this broader enterprise.

Watson considers this a seminal moment, the start of an avalanche that progressed into the 20th and 21st centuries. “Convergence” is his whirlwind exploration showing us “how linking one science with another could amplify understanding . . . converging and coalescing to identify one extraordinary master narrative, one overwhelming interlocking coherent story: the history of the universe.” When geologists revealed the time required to form sedimentary rock and paleontologists found fossils within those layers, questions inevitably arose concerning the origin of species, culminating in the work of Charles Darwin and Alfred Russel Wallace. Their work, in turn, would influence Karl Marx in his Darwinian model of societal change.

Physics came to affect chemistry, chemistry entered into biology, and biology impacted the cognitive sciences. Watson offers the reader a “big history” of the modern sciences from this specific perspective. Those seeking a grand overview of science’s greatest hits over the past century will find it here.

"Convergence: The Idea at the Heart of Science," by Peter Watson ( Simon & Schuster)

The first wave in this amalgamating march was dominated by the application of physics to an array of fields. Dmitri Mendeleyev found a distinct periodicity in the properties of the chemical elements that hinted at an underlying structure, which was ultimately revealed by physicists who discovered that the arrangement of electrons around a nucleus of protons and neutrons determined an element’s chemical behavior. The chemist Linus Pauling, absorbing the new laws of quantum mechanics that described the behavior of those electrons, was able to go even further, explaining in the 1930s the mechanisms behind elements bonding to one another to form molecules. This transformed the field of chemistry. And Pauling didn’t stop there. In the succeeding decades he played a vital role in taking this newfound knowledge into biology, helping forge the field of molecular biology.

Watson chose a dynamic time in science to summarize. So, because of the wide breadth of discoveries being described, the presentation can at times feel rushed. The achievements of a list of notables — from Wilhelm Rontgen to Henri Becquerel to Pierre and Marie Curie, for example — are condensed to a few pages. The arc from artificial dyes to pharmaceuticals is swept through in just several more. It is when Watson slows his pace to go deeper into a particularly pivotal development that the book becomes more engaging.

One such episode is the “friendly invasion of the biological sciences by the physical sciences,” as described by Rockefeller Foundation official Warren Weaver, who persuaded his organization to fund this new venture. Physicist Erwin Schrodinger started the stampede in the early 1940s with his influential book “What is Life?,” in which he suggested that the gene, then a mysterious entity, must be a highly stable molecule that contains a code. A decade later, two avid fans of Schrodinger’s book, James Watson and Francis Crick, finally cracked that code. The application of physics to astronomy has wielded similar revolutions in our understanding of stellar and cosmic evolution. The author goes on to examine the development of such paired scientific entities as sociobiology, behavioral economics, evolutionary psychology and cognitive neuroscience.

These direct meldings of scientific fields get less tight in the closing chapters. The author, for example, shows how scientists traced the origin of the Indo-European mother tongue to Anatolia around 6500 BC. It’s a fascinating journey, but this result did not involve an actual union of sciences. It was the evidence, separately arriving from archaeology, linguistics and genetics, that converged on a common answer.

With the rise of computation and information theory, it’s likely that future convergences will more and more involve mathematics — as the author puts it, “Whether order, as defined by mathematical equations, is not just an organizing principle of reality, but reality itself.” Unfortunately, while exploring this fascinating question, Watson goes off the path of settled science. He offers in due course wild and speculative imaginings, the pet theories of a handful of scientists that are not yet ready for prime time, such as physicist Frank Tipler’s views on the “physics of immortality.” I would have preferred that “Convergence” stuck with scientific information that is either well understood or testable. I think Mary Somerville would have agreed.

Convergence
The Idea at the Heart of Science

By Peter Watson

Simon & Schuster. 543 pp. $35