Human nature being as it is, every decade or two someone has to write a book to set us straight and cheer us up.

People all too readily overlook astonishing improvements in their condition as they rapidly become parts of daily life; they swallow uncritically assertions that disaster waits around the corner. But from time to time works of scholarship, sometimes dry and sometimes sly, debunk the doomsayers and remind us how fortunate we are to be alive in these times.

During the 1970s, it was futurist Herman Kahn and his merry band at the Hudson Institute who demolished the "limits to growth" forecasts of the Club of Rome cognoscenti — think Davos before it was invented — that the world was about to run out of darn near everything. In "The Next 200 Years" and "The Resourceful Earth," Kahn and his collaborators piled fact upon fact to argue the opposite, that an era of unprecedented growth and abundance was about to open.

The debate was memorably settled in 1980 when Hudson's Julian Simon proposed a wager to leading doomsayer Paul Ehrlich. The wager: Ehrlich would pick any five commodities he liked and bet $10,000 that during the next decade they would rise in price rather than fall, indicating increasing scarcity.

Simon won easily — Ehrlich was 0-for-5. But he could afford it, as the author of the bestselling and equally wrongheaded "The Population Bomb" (1968) and the recipient of a $345,000 "genius" grant from the MacArthur Foundation in 1990 — the same year he lost the bet. (MacArthur should have asked for a refund.)

But lamentations of impending economic, social and environmental catastrophe grow back like pests on an organic farm, and the record of progress periodically needs to be re-established. Demographer and author Ben Wattenberg took his turn in 1984 with the whimsical but fact-laden "The Good News Is the Bad News Is Wrong." Among his many bracing observations: The increased incidence of cancer wasn't a sign of an epidemic; it showed that people were living longer and not dying of other causes.

In our day, the task of rebutting the pessimists has fallen to Harvard cognitive psychologist Steven Pinker, whose contribution is the best one yet. In "Enlightenment Now," Pinker catalogs the irrefutable evidence that "life has gotten longer, healthier, richer, safer, happier, freer, smarter, deeper, and more interesting," through the application of reason, science and humanism. It is only the abandonment of those Enlightenment ideals, he says, that can threaten humankind's continued upward trajectory.

One by one, Pinker exposes alleged crises as overhyped, misrepresented or, in many cases, just plain wrong. Deaths from war and genocide have plummeted; genuine poverty and hunger are in steep decline, and famine has virtually disappeared; economic inequality is vastly overstated in the United States and is shrinking dramatically worldwide.

Life expectancy in the poorest country on Earth is now nine years greater than it was in the richest country two centuries ago.

Pick your favorite worry and it's likely to be getting better, not worse. Deaths from car and plane crashes, drownings and workplace injuries are all way down.

If a 453-page book, dense with facts and averaging one chart or graph every six pages, can be a delightful read, this one is it. Pinker enlivens it with aphorisms from the past ("The Stone Age didn't end because the world ran out of stones") and of his own devising: "Despair springs eternal," and "Those who call themselves progressives really hate progress."

In touting the epistemological superiority of science, the book is harshly dismissive of religion. Pinker strikes out at "right-wing politicians" and their disrespect for empirical facts. But he is equally direct in criticizing "politicized repression of science … from the left" on matters such as overpopulation and genetically modified organisms.

Where Pinker goes beyond his doom-dispelling predecessors is in explaining why so many people so readily accept pessimistic predictions or wild conspiracy theories. He walks the reader through such phenomena as the "availability heuristic" (we overestimate the frequency or probability of things that are shocking or otherwise memorable), "negativity bias" (we dread losses more than we enjoy gains, dwell on setbacks more than we savor good fortune) and "identity-protective cognition." We are awash in this last syndrome today, on both left and right, as "certain beliefs become symbols of cultural allegiance," however unfounded those beliefs may be.

Given the way we humans take progress for granted, "enlightenment now" will not be the last corrective required. Somewhere out there a farsighted doctoral student should start collecting data for the next era when, despite all the evidence, people are disinclined to believe that life is getting better.

Mitch Daniels is president of Purdue University and a former governor of Indiana. He wrote this article for the Washington Post.