Tempus fugit.

Time seems an appropriate topic for the first post of a new year, particularly when the new year is also taken by many as the first year of a new decade. I feel compelled to write "by many" to acknowledge that the question of whether decades properly begin with years ending '-0' or '-1' is still a contested one, even though most take the answer for granted. The fact that the way decades are defined is a matter for debate should give us all pause, reminding us that time is not as objective or 'real' as we may be tempted to imagine. Our collective understanding of the past owes as much to the selective arrangement and interpretation of past events as to actual chronology: as a result, products of historical memory like 'the Sixties' or 'the Eighties' are not synonymous with particular decades understood merely as units of measured time.

Christopher Caldwell has some interesting things to say about our experience of time in a column published on New Years' Day in the Financial Times. Caldwell finds that "time is really speeding up," at least insofar as we view the events of our lifetime with an immediacy that belies their actual proximity to the present:

We are now a decade into the 21st century, and off to a bad start. Decades almost always have their partisans - hippies liked the 1960s, socialists liked the 1970s, capitalists liked the 1980s and techies liked the 1990s. But the past decade has few defenders, if we leave aside terrorists and aficionados of decline.

Maybe it is odd that the decade passed so quickly. Unpleasant things are supposed to drag on and on: dentists' visits, workplace orientation sessions, almost all speeches. Yet no one complains that "this decade seemed to last 15 years." Decades never do. Time may slow down from hour to hour, but from year to year it has a uniform tendency to accelerate.

We can demonstrate this with a little game. We are now in the year 2010. Measure the number of years back to a certain event in your life - say, your entry into university, if you attended one. Then measure the same number of years back from there. Invariably, the event in the middle will seem closer to this date than to the older date, even though it is equidistant from the two.

This works with political events as well. George W. Bush's presidency seems extremely recent. Some might even call it an open wound. Yet not all of it is that recent. Mr Bush's election (2000) is as close to Margaret Thatcher's premiership (1979-90) as it is to David Cameron's (2010 - if we take one of the safer-looking political bets of the coming months).

How about Bill Clinton? Is he a present-day president? Sort of, but his election (1992) is as close to Richard Nixon's administration (1969-74) as to today. While we're at it, Baroness Thatcher's selection as Tory leader (1975) is as close to Neville Chamberlain's government (1937-40) as it is to us.

Putting things into quantitative chronology rather than sentimental chronology can lead us to reassess a lot of historical prejudices. How new a country is the US? Benjamin Franklin's birth in Boston (1706) is nearly as close to Dante's and Chaucer's 14th century as it is to the present. That makes the US seem positively ancient, not really a New World at all any more. On the other hand, to know that Ronald Reagan's birth (in Tampico, Illinois, in 1911) is closer to Waterloo (1815) than it is to us makes the country sound as if it were just founded. How recent a problem is the automobile? Well, the first car that Karl Benz manufactured (1885) is as close to the reign of George II (1727-60) as it is to us. How modern an ideology is communism? Marx's and Engels's Communist Manifesto (1848) is closer to the English and Scottish Stuart monarchy (which ended with the Glorious Revolution in 1688) than to us.

As Caldwell points out, our collective understanding of history mirrors the way that we understand past events in our own lives. Whether a particular event or phenomenon seems close or far away in time depends in large part on whether or not we experienced it personally:

. . . The older events are, the vaguer they get, but things you have lived through remain vivid. A pop song that was a hit seven years after you were born is wrapped up in all kinds of memories and associations. A pop song that was a hit seven years before you were born is part of the history you need to be told about. Particularly if you don't read much, it gets stored in the same mnemonic trivia bin that holds the epigrams of Marcus Aurelius, the Norman conquest, the Mona Lisa, the UK's General Strike of 1926 and "Yes, We Have No Bananas."

But there is another way in which this acceleration of time is not an illusion but a reality. Although we organise our lives around time measured chronometrically, chronometry is not the way we instinctively measure time.

The relevant instinctual unit we use to reckon time's passage is the lifetime - not some hypothetical lifetime drawn from actuarial tables, but your actual lifetime as you understand it concretely at a given moment.

So for a six-year-old, a year takes up a sixth of a lifetime, and that is a vast amount of time - think of how much you learn, how much you can change in a sixth of a lifetime. That's 10 times as much "time" as a 60-year-old can fit into the span of a year. The more the years pass, the narrower they look as spaces for living life in.

The above explanation of things makes sense to me, though I'll admit that it's a bit odd to realize that the year I graduated high school was closer to the presidency of Ronald Reagan than that of Barack Obama, or that the year I started kindergarden was closer to the assassination of President John F. Kennedy than to the present. Indeed, I can even say that my birth year is closer in time to the reign of Pope Pius XII than to that of Pope Benedict XVI. None of this makes me any older than I did before, but I can say I've acquired a somewhat deeper appreciation of the interplay of time and memory. AMDG.