Novelist Louis Auchincloss complains angrily that "The horror of living in New York is living in a city without a history ... All eight of my great-grandparents lived in the city ... and only one of the houses they lived in ... is still standing. That's what I mean by the vanishing past." Less patrician New Yorkers, whose ancestors landed in America more recently, arriving there from the barrios of Puerto Rico, the villages of Eastern Europe or the plantations of the South, might voice their feelings quite differently. Yet the "Vanishing past" is a real phenomenon, and it is likely to become far more widespread, engulfing even many of the history-drenched cities of Europe.

Buckminster Fuller, the designer-philosopher, once described New York as a "continual evolutionary process of evacuations, demolitions, removals, temporarily vacant lots, new installations and repeat. This process is identical in principle to the annual rotation of crops in farm acreage – plowing, planting the new seed, harvesting, plowing under, and putting in another type of crop ... Most people look upon the building operations blocking New York's streets ... as temporary annoyances, soon to disappear in a static peace. They still think of permanence as normal, a hangover from the Newtonian view of the universe. But those who have lived in and with New York since the beginning of the century have literally experienced living with Einsteinian relativity."

That children, in fact, internalize this "Einsteinian relativity" was brought home to me forcibly by a personal experience. Some time ago my wife sent my daughter, then twelve, to a supermarket a few blocks from our Manhattan apartment. Our little girl had been there only once or twice before. Half an hour later she returned perplexed. "It must have been torn down," she said, "I couldn't find it." It hadn't been. New to the neighborhood, Karen had merely looked on the wrong block. But she is a child of the Age of Transience, and her immediate assumption – that the building had been razed and replaced – was a natural one for a twelve-year-old growing up in the United States at this time. Such an idea would probably never have occurred to a child faced with a similar predicament even half a century ago. The physical environment was far more durable, our links with it less transient.

In the past, permanence was the ideal. Whether engaged in handcrafting a pair of boots or in constructing a cathedral, all man's creative and productive energies went toward maximizing the durability of the product. Man built to last. He had to. As long as the society around him was relatively unchanging each object had clearly defined functions, and economic logic dictated the policy of permanence. Even if they had to be repaired now and then, the boots that cost fifty dollars and lasted ten years were less expensive than those that cost ten dollars and lasted only a year.

As the general rate of change in society accelerates, however, the economics of permanence are – and must be – replaced by the economics of transience.

First, advancing technology tends to lower the costs of manufacture much more rapidly than the costs of repair work. The one is automated, the other remains largely a handcraft operation. This means that it often becomes cheaper to replace than to repair. It is economically sensible to build cheap, unrepairable, throwaway objects, even though they may not last as long as repairable objects.

Second, advancing technology makes it possible to improve the object as time goes by. The second generation computer is better than the first, and the third is better than the second. Since we can anticipate further technological advance, more improvements coming at ever shorter intervals, it often makes hard economic sense to build for the short term rather than the long. David Lewis, an architect and city planner with Urban Design Associates in Pittsburgh, tells of certain apartment houses in Miami that are torn down after only ten years of existence. Improved air conditioning systems in newer buildings hurt the rentability of these "old" buildings. All things considered, it becomes cheaper to tear down the ten-year-old buildings than to modify them.

Third, as change accelerates and reaches into more and more remote corners of the society, uncertainty about future needs increases. Recognizing the inevitability of change, but unsure as to the demands it will impose on us, we hesitate to commit large resources for rigidly fixed objects intended to serve unchanging purposes. Avoiding commitment to fixed forms and functions, we build for short-term use or, alternatively, attempt to make the product itself adaptable. We "play it cool" technologically.

The rise of disposability – the spread of the throw-away culture – is a response to these powerful pressures. As change accelerates and complexities multiply, we can expect to see further extensions of the principle of disposability, further curtailment of man's relationships with things.

There are other responses besides disposability that also lead to the same psychological effect. For example, we are now witnessing the wholesale creation of objects designed to serve a series of short-term purposes instead of a single one. These are not throw-away items. They are usually too big and expensive to discard. But they are so constructed that they may be dismantled, if necessary, and relocated after each use.

Thus the board of education of Los Angeles has decided that fully 25 percent of that city's classrooms will, in the future, be temporary structures that can be moved around as needed. Every major United States school district today uses some temporary classrooms. More are on the way. Indeed, temporary classrooms are to the school construction industry what paper dresses are to the clothing industry – a foretaste of the future.

The purpose of temporary classrooms is to help school systems cope with rapidly shifting population densities. But temporary classrooms, like disposable clothes, imply manthing relationships of shorter duration than in the past. Thus the temporary classroom teaches something even in the absence of a teacher. Like the Barbie doll, it provides the child with a vivid lesson in the impermanence of her surroundings. No sooner does the child internalize a thorough knowledge of the classroom – the way it fits into the surrounding architecture, the way the desks feel on a hot day, the way sound reverberates in it, all the subtle smells and textures that individualize any structure and lend it reality – than the structure itself may be physically removed from her environment to serve other children in another place.

Nor are mobile classrooms a purely American phenomenon. In England, architect Cedric Price has designed what he calls a "thinkbelt" – an entirely mobile university intended to serve 20,000 students in North Staffordshire. "It will," he says, "rely on temporary buildings rather than permanent ones." It will make "great use of mobile and variable physical enclosures" – classrooms, for example, built inside railroad cars so that they may be shunted anywhere along the four-mile campus.

Geodesic domes to house expositions, air-inflated plastic bubbles for use as command posts or construction headquarters, a whole array of pick-up-and-move temporary structures are flowing from the drawing boards of engineers and architects. In New York City, the Department of Parks has decided to build twelve "portable playgrounds" – small, temporary playgrounds to be installed on vacant city lots until other uses are found for the land, at which time the playgrounds can be dismounted and moved elsewhere. There was a time when a playground was a reasonably permanent fixture in a neighborhood, when one's children and even, perhaps, one's children's children might, each in their turn, experience it in roughly the same way. Super-industrial playgrounds, however, refuse to stay put. They are temporary by design.