Seth Shulman, editorial director of the Union of Concerned Scientists, writes the syndicated monthly column “Got Science?” He is the author of six books including “The Telephone Gambit: Chasing Alexander Graham Bell’s Secret.”

The Moral Arc
How Science and Reason Lead Humanity Toward Truth, Justice, and Freedom

By Michael Shermer

Henry Holt.
541 pp.$32

‘The arc of the moral universe is long, but it bends toward justice,” the Rev. Martin Luther King Jr. told a crowd of protesters in Montgomery, Ala., in March 1965. King’s use of that quote stands as one of history’s more inspiring pieces of oratory, acknowledging that victories in the fight for social justice don’t come as frequently as we might like, while offering hope that progress will come eventually.

But is the contention empirically true?

‘The Moral Arc: How Science and Reason Lead Humanity toward Truth, Justice, and Freedom’ by Michael Shermer (Henry Holt)

Michael Shermer, a professor, columnist for Scientific American, and longtime public champion of reason and rationality, takes on this question and more. In “The Moral Arc,” Shermer aims to show that King is right so far about human civilization and that, furthermore, science and reason are the key forces driving us to a more moral world. It is at once an admirably ambitious argument and an exceedingly difficult one to prove.

First, Shermer — defining moral progress as “improvement in the survival and flourishing of sentient beings” — needs to make a case that we humans are, in fact, moving toward such an improvement despite terrorist attacks on cartoonists, Islamic State beheadings, Taliban massacres of schoolchildren and police shootings of innocent civilians, among other seemingly daily atrocities. As he notes in the preface, when they heard he was working on a book about moral progress, “most people thought I was hallucinatory. A quick rundown of the week’s bad news would seem to confirm the diagnosis.”

If that weren’t tough enough, Shermer also needs to show that science and scientific reasoning are responsible for bettering our lot. Given science’s role in everything from the development of the atomic bomb to pervasive government surveillance, it’s hard to know which of his self-appointed tasks is more daunting.

To his credit, Shermer tackles this broad agenda with an abundance of energy, good cheer and anecdotes on everything from “Star Trek” episodes and the reasoning of Somali pirates to the demise of the Sambo’s restaurant chain. The anecdotes provide leavening but don’t alter the fact that this is a work of serious and wide-ranging scholarship with a bibliography that runs to nearly 30 pages. The effect can be kaleidoscopic and even a bit scattershot at times, but that doesn’t detract from the truly impressive array of data Shermer assembles.

Consider, for instance, that Shermer walks through the nuances of studies charting the decline of deaths in warfare as a percentage of the human population from prehistoric times to the present; progress in the abolition of state-sponsored torture meted out by the judicial systems in 10 Western nations between 1650 and 1850 as these punishments came to be seen as “cruel and unusual”; cross-cultural comparison of progress in women’s voting rights throughout the 1900s in countries from Switzerland to Samoa; the decline in the number of U.S. death sentences between 1977 and 2013; and even the reduction in the world’s nuclear arsenals over the past several decades.

At its best, this kind of survey can be exhilarating in the service of such a grand thesis. I’ve spent most of my career chronicling issues in science and technology, and I now work with an organization (the Union of Concerned Scientists) that champions the use of science and evidence in policymaking as an antidote to the polarized political misinformation that seems more virulent than ever in U.S. politics. For readers like me — and I’m sure many others as well — it is of far more than passing interest if data can show that the scientific method and what Shermer calls the “public health model of moral science” have helped to guide humanity in a positive direction.

In something of a recent literary trend, others have tackled segments of Shermer’s grand argument. Perhaps most notably, Steven Pinker, in “The Better Angels of Our Nature,” did an impressive job of showing that, overall, violence has declined over the long sweep of human history. Meanwhile, Sam Harris, in his tautly reasoned book “The Moral Landscape,” made a strong case that there are right and wrong answers to moral questions and that science has something important to say about which are which.

Overall, Shermer does a good job of mining the scholarship in these and other areas, but his approach and the sheer breadth of scope ultimately make his argument seem more of a survey and less focused than some of these other works. He is at his strongest in presenting material such as the fascinating research by social scientist Gregory S. Paul that painstakingly analyzes 17 developed countries on a range of factors to find a striking correlation between a country’s level of religiosity and its dysfunction (as measured on such indices as homicides, suicides, divorce, income inequality, etc.). Somewhat less convincing are Shermer’s sections on the role of science as a moral force for good, which mostly boil down to anecdotes in which science has helped supplant superstition since the Enlightenment. It is true, of course, that (as far as I know) we’re no longer burning “witches” at the stake for phenomena we don’t understand. But I hoped Shermer would grapple more with the vexing ways in which science has contributed — and arguably continues to contribute — to moral atrocities, from the role of Nazi scientists to the development of biological weaponry.

Shermer’s case seems more anecdotal and even arbitrary than it should to really prove his grand case. Nonetheless, I enjoyed the book’s provocative breadth and found much of the material fascinating and well chosen. I greatly admire Shermer for tackling such an ambitious project and hope the book spurs many discussions and much further scholarship on this important subject.