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Comment by rcoveson | Hacker News Reader

Why are you counting from AD 1, which nobody alive at the time called AD 1?

It's natural to align the decades, centuries, an millennia with a decimal radix. You've got the year digit, the decade digit, the century digit, and the millennium digit. Decades are always talked about this way, e.g. "the 80's", and I'd wager that most people think about centuries and millenniums this way. The fact that the year number is defined as the ordinal year since the approximate birth of Christ, beginning with AD 1, doesn't strike me as particularly relevant.

In other words, I'm not "counting from" anything. I'm describing the decimal year number in a manner that's natural for the radix.

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It doesn't matter whether people of the time said AD 1 or not, because the BC/AD b system was adopted much later. It's confusing and ultimately pointless, but if you plant apple trees, the year in which you do that is the first year in which you planted apple trees, not the zeroth year. After ten years elapsed, it is now the tenth year of your apple tree planting phase.

I agree about your 80s example (of course I use it in the same way), but that doesn't change the fact that it ultimately doesn't make sense because you'll be off by one when counting backwards. So for colloquial conversations it's fine, for serious date calculations, you cannot just have one "decade" with only 9 years.

I understand the explanation, but your final statement is still wrong. If you're doing "serious date calculations" for any modern organization, and you are asked to make a graph of 20th century data by decade, you will be expected to use the standard decade divisions, i.e. 190_, 191_, 192_. If you include data from December 2000, and get different results from your colleagues, you have failed. The last decade of the 20th century was Jan. 1990 - Dec 1999, according to everybody except the most pedantic of history majors.

And the idea that you could actually do serious date calculations that count backwards all the way to AD 1 while maintaining a precision of 1 year is also ridiculous. There are error bars around the year numbers from that long ago of something like 2-5 years.

I understand the basis for the [1901-2000] definition. However, I really don't think its defense outweighs its huge downsides, especially the split-decade problem.

I just wanted to say that I appreciate the amount of thought you have put in your argument, even though I ultimately remain unconvinced by it.

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