[pdonis]

> What does that even mean?

It means just what it says. In the common calendar, the year after 1 BC (or BCE in the new notation) was 1 AD (or CE in the new notation). There was no "January 1, 0000".

[hgomersall]

As I said twice, whether that date actually existed or not is irrelevant.

[pdonis]

> whether that date actually existed or not is irrelevant.

No, it isn't, since you explicitly said to start the first century on the date that doesn't exist. What does that even mean?

[lupire]

The first day of the 1st Century is Jan 1, 1 AD.

The point is that some days got skipped over the centuries, but there's no need to make the Centuries have weird boundaries.

[pdonis]

> The first day of the 1st Century is Jan 1, 1 AD.

That's not what the poster I originally responded to is saying. He's saying the 1st Century should start on a nonexistent day.

[antonvs]

You can make this work by having the 1st century start on the last day of 1 BC. Think of it as an overlap if you like; it doesn't really matter.

That allows for consistent zero-indexed centuries. It doesn't have any other practical consequences that matter.

[hgomersall]

No, I'm saying we ignore when it actually started and instead use the normal rules of counting to decide what to call the respective centuries.

[zarzavat]

0 CE = 1 BCE

10 C = 50 F = 283.15 K

1 = 0.999…

Things can have more than one name. The existence of the year 0 CE is not in question. What’s in question is whether that’s a good name for it or not.