For weeks now, we've been marking time. Wrapping up the past 10 years in words as if they were being prepared for storage. Waiting to open up the next decade like a present or a Pandora's box.

Dozens of us have ritualistically rifled through all the "stuff" of the Seventies and sat down to write instant histories on decade deadlines.

We've edited in and edited out the memorabilia -- a no-smoking sign, a Nixon button, a jogging suit -- in search of a handle or a headline that would fit on a card catalog. We call it the Me Decade, the Slippage Seventies, the National Mid-Life Crisis Years. We are, in fact, willing to call it anything at all so long as we can file it away neatly beside the Roaring Twenties, the Silent Fifties and Radical Sixties.

Soon we'll be standing in some Times Square or huddled around some timepiece waiting for the takeoff of the 1980s. On New Year's Eve, even the most blase will watch the clock the way we watch the speedometer for the 100,000-mile change.

I don't know exactly why we are so compulsive about celebrating the passage from one arbitrary "decade" to another. I'm not sure why we go through this ceremony of summing up, or why we behave as if there were something mystically meaningul in a bunch of man-made digits.

But I think it has a lot less to do with history than with psychology. I think it says somethings about our peculiar human relationship with the terrifying, impersonal vastness called Time.

Time itself doesn't have years, weeks, decades. "Time has no divisions to mark its passing," Thomas Mann wrote. "There is never a thunderstorm to mark the beginning of a new month or year."

So we make our own thunderstorms, our own calibrations and celebrations, with hats and horns, summaries and predictions. We take time, which has no human scale, and bring it down to our size. We chop the eternal into life-sized pieces: the 1970s, the 1980s.

The task of summing up, culture-reading, has all the authenticity of palm-reading. It is by definition impossible for contemporaries to write their own history. We only have 20-20 vision in hindsight and rarely even then.

There has been nothing more or less special about the 1970s than about the 970s. What has seemed tumultuous may someday look like a quite era whose only legacy was designer jeans.

Ten years is an extraordinarily small piece of time-change. But it is a huge chunk of our own lives. So, when we look into the mirror of a decade, we see reflected back our own egos. We see what a huge impression the years made on us and want to believe that we returned the gift. We try to contain a continuum, to impose numbers on it, progress on it. We give one decade a larger-than-life label and a proper send-off and wait for the next with noisy greeting.

We flatter ourselves with the notion that the years we live through have been and will be large and memorable -- too important to be ignored. We flatter ourselves with the notion that we have lived in the best or worst of time, in order to avoid the frightening idea that we may have lived through the most forgettable of times.

We would rather be part of a Me Decade than a void.

So, maybe at the end of a decade, at New Decade's Eve, we aren't toasting the passage of time at all, but of ourselves. "Time goes, you say?" asked the poet Henry Dobson. "Alas, Time stays, we go."

For a moment, for a midnight at least, we try to clock infinity. We try to truly mark time.