The idiots in Silicon Valley — many of whom aren’t yet old enough to have experienced adventures of aging like getting a colonoscopy — seem to picture “life-extension” as though it means more time to improve one’s tennis strokes in a future turned into a never-ending vacation. But what life extension will much more likely simply mean is prolonged infirmity.

If it was possible to build an economy around “health care” — which should much more accurately be called disease management — then the prospect of a perpetually expanding population of the infirm might look like a golden business opportunity, but what we’re really looking at is an economy built on false promises.

Daniel Callahan writes: This fall Google announced that it would venture into territory far removed from Internet search. Through a new company, Calico, it will be “tackling” the “challenge” of aging.

The announcement, though, was vague about what exactly the challenge is and how exactly Google means to tackle it. Calico may, with the aid of Big Data, simply intensify present efforts to treat the usual chronic diseases that afflict the elderly, like cancer, heart disease and Alzheimer’s. But there is a more ambitious possibility: to “treat” the aging process itself, in an attempt to slow it.

Of course, the dream of beating back time is an old one. Shakespeare had King Lear lament the tortures of aging, while the myth of Ponce de Leon’s Fountain of Youth in Florida and the eternal life of the Struldbrugs in “Gulliver’s Travels” both fed the notion of overcoming aging.

For some scientists, recent anti-aging research — on gene therapy, body-part replacement by regeneration and nanotechnology for repairing aging cells — has breathed new life into this dream. Optimists about average life expectancy’s surpassing 100 years in the coming century, like James W. Vaupel, the founder and director of the Max Planck Institute for Demographic Research in Germany, cite promising animal studies in which the lives of mice have been extended through genetic manipulation and low-calorie diets. They also point to the many life-extending medical advances of the past century as precedents, with no end in sight, and note that average life expectancy in the United States has long been rising, from 47.3 in 1900 to 78.7 in 2010. Others are less sanguine. S. Jay Olshansky, a research associate at the Center on Aging at the University of Chicago, has pointed out that sharp reductions in infant mortality explain most of that rise. Even if some people lived well into old age, the death of 50 percent or more of infants and children for most of history kept the average life expectancy down. As those deaths fell drastically over the past century, life expectancy increased, helped by improvements in nutrition, a decline in infectious disease and advances in medicine. But there is no reason to think another sharp drop of that sort is in the cards.

Even if anti-aging research could give us radically longer lives someday, though, should we even be seeking them? Regardless of what science makes possible, or what individual people want, aging is a public issue with social consequences, and these must be thought through.

Consider how dire the cost projections for Medicare already are. In 2010 more than 40 million Americans were over 65. In 2030 there will be slightly more than 72 million, and in 2050 more than 83 million. The Congressional Budget Office has projected a rise of Medicare expenditures to 5.8 percent of gross domestic product in 2038 from 3.5 percent today, a burden often declared unsustainable.

Modern medicine is very good at keeping elderly people with chronic diseases expensively alive. At 83, I’m a good example. I’m on oxygen at night for emphysema, and three years ago I needed a seven-hour emergency heart operation to save my life. Just 10 percent of the population — mainly the elderly — consumes about 80 percent of health care expenditures, primarily on expensive chronic illnesses and end-of-life costs. Historically, the longer lives that medical advances have given us have run exactly parallel to the increase in chronic illness and the explosion in costs. Can we possibly afford to live even longer — much less radically longer?

At the heart of the idiocy which Silicon Valley cultivates are a host of profound misconceptions about the nature of time.

Having become slaves of technology, we take it as given that time is measured by clocks and calendars. Life extension is thus conceived in purely numerical terms. Yet the time that matters is not the time that can be measured by any device.

That’s why in an age in which technology was supposed to reward us all with extra time, instead we experience time as being perpetually compressed.

Having been provided with the means to do more and more things at the same time — text, tweet, talk etc. — our attention gets sliced into narrower and narrower slivers, and the more time gets filled, the more time-impoverished we become.

For the narcissist, there can be no greater fear than the prospect of the termination of individual existence, yet death is truly intrinsic to life. What it enables is not simply annihilation but more importantly, renewal.