31 December, 2009

Decades, centuries, millennia, you're all wrong!

Some people are all wrapped about today being the end of a decade. They're out getting extra drunk right now to commemorate the event.

Others are all wrapped up about it not being the end of a decade, because we have no year zero. Since the numbering system starts with 1—there being no year 0 AD—decades start in years ending with a 1, so the decade doesn't end until next year. So there, says they, exchanging smarmy glances of intellectual superiority betwixt themselves. It will surely dismay them that the first group will be none the sadder for the opportunity to get extra drunk next year, too. Tho there, theth they. (hic)

Well, says I, two can play that game. As a matter of fact, we do have a year zero, it's just that we tend to call it 1 BC instead of 0 AD. Likewise, we have a year -1, but we call it 2 BC. And so forth. You can, in fact, start a decade on a year ending with zero, so today is, in fact, the last year of a decade.

But, says the mathematician in me, it gets better, because it's merely a frame of reference. You can start a decade anytime you want: in a year ending with zero, ending with one, or even ending with π if such a thing existed. (It is, in fact, quite possible to imagine a year ending in π—quite natural, even. Maybe I shall go into the details in a later post.)

If you think I'm being disingenuous, then let me ask, How old are you? And whatever you answer, do you count from the first of the year in which you were born, from the date of your conception, or from the date of your birth? If you don't count from January 1 of the year in which you were born, why not?

The point is, it's all relative to whatever start date you choose. If someone wants to start his decade in 2000 and end in 2009, who else would begrudge him but a smarter-than-thou killjoy who thinks it's more important to feel superior (while being wrong) than to have a little fun?

I felt the same way over the furor about the new millennium ten years ago, too. Look: the new millennium started when the Age of Endarkenment began: on my birthday, which was (far too) long before 2000, 2001, or any of that Y2K nonsense. All you ignoramuses who argued about when the new millennium began were wrong. Now go out and have fun!


Clemens said...

Old hat for a medieval historian. I work with documents that were dated from the Christian era, but there were several notions of what year started that. And then there was the question of WHAT you were dating from: the birth of Christ, or his Resurrection? Both opinions operated. And when to begin the year? At the end of the old pagan year, on 1 January? Or on Easter Day? Try figuring that last one out. I've dealt with too many acts dated from the Resurrection counting the first few months of the year as the LAST year.

So let's just call the Aughts, or the Double Zeros, or whatever, a "notional decade."

Don't know about you but I am going to go have a drink to celebrate.

(Happy New Year to you and your family. Or are you on the Russian Orthodox calendar?)

jack perry said...

Every now and then I think I will resurrect dating by AUC (Ab Urbe Condito). But I didn't realize that some dated from Easter Day.

Russians celebrate New Year's Day according to the Gregorian calendar, but Christmas according to the Julian Calendar. The former is secular, which helps. The latter is religious, so…

Clemens said...

Well, I know some Greeks from Tarpon Springs. They celebrate Epiphany with great gusto.