Before this year is out, I will turn 60 -- a nice round number, if not exactly a ripe old age. It's the sort of milestone, I hope, that might excuse an aspiring codger's ruminating about the times he's lived through.

I promise not to dwell on how much the world has changed for the worse since I was a boy. I'm too concerned just now about how little the world has changed for the better.

I mean that progress in my time sometimes seems to have been surprisingly modest in material things -- in the nuts and bolts and stuff of life, the facts of physical existence that humanity has always wanted to improve upon. Social life, for its part, has changed plenty, in ways both good and bad. But that's the stuff of a different rumination.

In these days of economic discontent, it might shed light on our challenges to at least consider what may at first blush seem improbable -- that we may have passed quietly into a new historical era, an age that has not been marked by the same steady stream of revolutionary, life-changing innovation and scientific breakthroughs the world had known for the better part of two centuries by the time my baby boom generation was born.

It's obviously not that we live in a stagnant time, barren of economic progress and technological marvels. But we boomers were born into a world that truly had been transformed, and then transformed again, within a lifetime or two. The world was 150 years or so into an era in which humanity's very place in the order of nature had seemed to shift. In which economic growth had, you could almost say, been invented.

My lifetime, it seems to me, hasn't kept up that pace. When I was a kid, people drove cars and flew in airplanes, listened to radio and watched television and went out to movies, lighted their homes and powered their toasters and refrigerators with electricity and took antibiotics when they were sick. It wasn't all that different a world.

Without doubt the fabulous Internet, with all its technological servants, is the most admired innovation of our age. But if tomorrow the world awoke to find it had lost both the Internet and the major advances of earlier times -- the internal combustion engine, say, or electricity itself -- would it be our smart phones we would miss the most, or the longest?

The year I graduated from high school (1970, if you must know), a book called "Future Shock" by Alvin Toffler became a sensational best-seller. Toffler's theme was that the modern world's ever-accelerating technological changes were and would remain more than human beings could comfortably adapt to. Something like that may have been true for my generation's parents and grandparents (although they seemed to rather like modern conveniences), because in their lifetimes change surely had been dizzying, with everything from electricity and telephones, to automobiles and airplanes, to radio and television, to plastic and atomic power bursting upon the world.

But today the warnings of "Future Shock" sound oddly old-fashioned, like a lot of extravagant expectations people had for the "world of tomorrow" when I was a kid. I am seldom shocked by the technological "future" I find myself in after six decades of life. Often impressed, sometimes annoyed, but seldom shocked.

A noted 2011 book, "The Great Stagnation," better explains how I feel about my lifetime. In it, economist Tyler Cowen argued that Americans, largely unawares, have found themselves atop a "technological plateau" over the past 40 years or so. Innovations have been fewer and less economically powerful, Cowen says, and it is mostly this that explains decades of significantly slower rates of economic growth in rich nations like the United States.

Cowen blames the innovation and growth plateaus -- and especially our ignorance of them -- for much of what ails America today. The lingering financial crisis, he argues, is at bottom the result of outlandish private and public debt incurred in a vain attempt to sustain the kind of rapid lifestyle improvements the nation had grown accustomed to during earlier times and assumed were somehow inevitable. Our dysfunctional politics, he says, is likewise a symptom of denial, as politicians grasp for a simple answer -- too much government intervention, or not enough -- to explain our unsettling inability to produce the expected gains in prosperity or even to see how we'll ever pay for promises already made in, say, Social Security and Medicare.

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The suspicion that history may have turned a page from something like future shock to something like a great stagnation, undermining our era's cherished self-image as a time of dazzling, even disconcerting change, goes back a ways for me. Some years ago, for an article series and book about Minnesotans' experience of the 20th century, I borrowed a quote from an old editorial in the St. Paul Pioneer Press (where I then worked). Celebrating the arrival of a new century on Jan. 1, 1901, the editorial had predicted an inevitable slowdown in the pace of change after the astonishing 1800s:

"So much has already been accomplished in the way of purely material development that in this direction future progress may not be as striking. ... Not probably in the Twentieth Century will the world be again so startled as it was by the adaptation of steam power to the purposes of manufacture and transportation, and by the 'chaining of the lightning' to the telegraph, the telephone and the trolley."

Adorably quaint, of course. I observed that a few striking advances still lay ahead -- cars and airplanes, radio and television, computers and organ transplants, space travel and cloning among them.

Yet all the same, didn't the 19th-century futurist have a point? His era's introduction of electricity, motorized power, instantaneous communication, mass production and more -- to a world still stumbling around in the dark and moving at the speed of horses -- may have transformed daily existence more than any later application of those wonders. Or at least it may have been more amazing.

Julius Caesar would not have found the world of 1800 drastically unfamiliar. By 1900, future shock had set in but good. The editorialist's phrase "the chaining of the lightning" captures a sense of science as sorcery that nothing before the 19th century and little since has truly matched.

More to the point of the pace of change in the more recent past is this: That list of 20th-century marvels that I latched onto to ridicule 19th-century chauvinism contained, without my planning it, mostly wonders that had come to pass by the time I was born in 1952 -- especially the ones on the list that transformed everyday life and created vast industries.

Even space exploration was at hand in 1952. I was only 16 when Neil Armstrong, who died at 81 this year, set foot on the moon.

"This changes everything" goes today's overused hyperbole. But if "everything" ever did suddenly change, it was awhile ago. English scholar and author C.S. Lewis argued in 1954, two years after my birth, that the most momentous division in all of human history separated the mid-20th century from the early 19th century of Jane Austin and Sir Walter Scott. The "trump card" that made it the greatest transformation of all, he said, was the original "birth of the machines" -- an event that could not be compared with anything else in "history" at all, but only with prehistoric turning points like the advent of agriculture or the domestication of animals.

Innovation in our time doesn't seem quite like that, but more like what another Englishman, G.K. Chesterton, described in his autobiography:

"I am just old enough to remember ... the world before telephones. And I remember that my father and my uncle fitted up the first telephone I ever saw with their own metal and chemicals, a miniature telephone reaching from the top bedroom under the roof to the remote end of the garden. I was really impressed imaginatively by this; and I do not think I have ever been so much impressed since by any extension of it ... It did startle me that a voice should sound in the room when it was really as distant as the next street. It would hardly have startled me more if it had been as distant as the next town. It does not startle me any more if it is as distant as the next continent. The miracle is over."

Cars and airplanes, radio and television, highways and skyscrapers, air conditioning and radar, therapeutic drugs and surgical techniques have all been improved and extended since my childhood -- greatly improved and extended in many cases. But they existed in the world I entered.

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How much more daily life changed for an imaginary figure I have come to think of as "Grandfather." He was born in 1892 and turned my current age, 60, the year I was born. All of the things I just listed essentially came into the world between his birth and mine. He was born into a world without aspirin. The technology for electricity and indoor plumbing existed when Grandfather was born, but they were almost unheard of in private homes.

Health and medicine may seem an exception to this pattern, for surely advances in the past 60 years have been remarkable. But earlier changes were again more fundamental. Average American life expectancy at birth rose about 40 percent between 1900 and 1950, from about 49 to about 68. It rose only another 15 percent by 2007, to about 78, mainly by extending life for the elderly.

But what of the wonderful world of computers, the Internet, social networking and all the rest? Well, it is wonderful. It has enriched our lives and our public debate; its power to enhance economic efficiency, communication, research, engineering and more has scarcely begun to be tapped. It may well turn out to be a world-changing innovation that makes our age the equal of any other. But it hasn't done so yet.

Cowen notes that for all its benefits, the Internet has yet to produce giant industries employing millions and generating powerful streams of private and public revenue.

My own candidate for the most momentous innovation of my lifetime would be the birth-control pill -- a true liberation from an ancient biological tyranny that has had immense personal and economic effects.

Anyway, this whole impression that progress has slowed could be wrong. Or breakthroughs in any of a hundred fields could make it wrong tomorrow. And living in a period of less startling innovation need not be seen as tragic. In recent decades, the extension of long-existing technologies to millions in once desperately poor parts of the world has produced a genuine economic miracle -- a miracle that isn't over.

But it's always useful to know where you really are. Maybe we're not riding the crest of the history's greatest wave of scientific progress. Maybe the big one has passed, and we're waiting, hoping, for another.

D.J. Tice is at dtice@startribune.com.