We know what 1914 means. It means the beginning of World War I. We know what 1938 means. It means appeasement at Munich in the run-up to World War II. We know what 1968 means. It means the assassinations of Martin Luther King Jr. and Robert F. Kennedy, rioting at the Democratic National Convention in Chicago and the election of Richard M. Nixon. But what will 2009 mean?

Will we think of 2009 as the year the recession deepened? Or as the year the recovery began? As the year Barack Obama was inaugurated? Or the year the Obama magic faded? As the year water was found on the moon? Or as the year the World Digital Library began?

How about the year the Air Force ordered 2,200 Sony PlayStation 3 video game consoles, a signature convergence of video games and warfare? And if musicologists think 1750 is a landmark because it was the year J.S. Bach died, might 2009 be remembered as the year Michael Jackson left us?

We use years as shorthands all the time, revealing our biases and our perspectives.

Are you the kind of person who thinks of 1917 as the year the United States entered World War I or the very different kind of person who thinks of 1917 as the year the Communist revolution occurred in Russia? Are you the sort who thinks of 1848 as the year the Mexican War ended or as the year Europe was convulsed in revolution?

Is 1804 the year of the Eroica Symphony or the year Napoleon crowned himself emperor? Your answer depends on whether you revere Ludwig van Beethoven (whose symphony had its premiere that summer) or Jacques-Louis David (whose painting of that year’s contentious coronation was completed later in the decade).

Different cultures have different touchstones. For Jews, it is 70 A.D., when the Second Temple fell. For the Bosnians it is 1463, the year of the Ottoman conquest. For the Irish it might be 1690, when the Battle of the Boyne was fought, or maybe 1916, the year of the Easter Rebellion.

We think of 1974 as the year Richard Nixon resigned, but in the Mediterranean, it is the year the Turks moved on the Greek Cypriots. In Iraq, 1921 is remembered as the year of the crowning of King Faisal I. But in Danville, Ky., the year 1921 is remembered for only one thing, and if you ask what it is you immediately identify yourself as someone who did not attend Centre College, whose valiant football team that October beat Harvard, until then undefeated in two seasons, 6-0.

Where you stand on these sorts of things says a lot about where you sit, especially if you’re sitting in a university. If you’re sitting in the economics department or the history department, 1933 is the year of the New Deal (though the phrase came from Franklin D. Roosevelt’s acceptance speech at the Chicago convention a year earlier). But if you are in the Russian department, 1933 is the year FDR recognized the Soviet Union. And if you are in the German department, it’s the year Adolf Hitler took power.

Then again, if you are in the athletic department, it’s the year of the first NFL championship (Bears 23, Giants 21), unless of course the athletic department you’re sitting in is at the University of New Hampshire (or at my house), where without prompting you may know that 1933 is the year when the first racing ski trail was cut (Taft Trail at Cannon Mountain).

It also depends on when you are looking.

Three-quarters through 1941 you might have been sure that the year would be remembered for baseball heroics, two remarkable personal performances in one remarkable summer season. That year Joe DiMaggio hit in 56 consecutive games and Ted Williams finished the season batting .406. The DiMaggio record never has been surpassed, and in the ensuing two-thirds of a century not one baseball player has finished over .400.

So the opening theory would be that 1941 in America would be remembered for performances at the plate. But mention 1941 today and hardly anyone thinks the performances of the Yankee Clipper and the Splendid Splinter are the most important things that happened that year. (Is history taught so badly today that we here have to mention that the Japanese attacked Pearl Harbor on Dec. 7, 1941?)

At the end of 1979 you reasonably could have concluded that the seizure of American diplomats as hostages in Iran was the most important event of the year. It traumatized the country and symbolized the fecklessness of Jimmy Carter’s diplomacy. Now it may seem that either of two other events that year was more important, Pope John Paul II’s visit to Poland (which may have set in motion the forces that toppled Soviet Communism) or the Soviet invasion of Afghanistan (which may have set in motion the forces that toppled the World Trade Center).

Then again, if Iran acquires and uses a nuclear weapon, we may in our saddened world look back on that year and conclude that forevermore 1979 should be remembered for the Islamic Revolution in Iran. The past is like that. It changes more than you think.

Which is why we may conclude that the year 2009 might not be so bad after all.

We don’t know today, for example, what game-changing invention was conceived this year (hardly anybody celebrated the invention of the Web in 1989) or which world-changing individuals were born this year (we now know that both Abraham Lincoln and Charles Darwin were born 200 years ago, facts that were of no apparent significance outside the Lincoln and Darwin families in 1809). We don’t know which for-want-of-a-nail event in some faraway corner of the world may set in train a revolution — in politics, economics, medicine, literature, music — that will change our world forever. For all we know now, 2009 might be a year to remember rather than one to forget.