Please explain my confused me like I’m 5 (0r 4 or 6).

  • CanadaPlus@lemmy.sdf.org
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    7 months ago

    If we were starting from scratch, it would probably be better to go with two year zeroes, so it would fit normally into positional number systems, and then you could even talk about 0.5AD for the relevant summer.

    Unfortunately, positional numbering wouldn’t be invented in the old world until hundreds of years after the Christian calendar.

    • jsomae@lemmy.ml
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      7 months ago

      The only positional numbering system I use daily (base 10) has only one zero. What system are you talking about?

      • CanadaPlus@lemmy.sdf.org
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        7 months ago

        Oh really? What do -0.25 and 0.25 both start with, and round to?

        A reminder to read the original reply that started this thread. There’s two “zero-areas” between the one points and the zero point.

        • jsomae@lemmy.ml
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          7 months ago

          Ah, I see. You’re advocating for naming the intervals (0, 1) and (-1,0) by rounding toward zero rather than away from zero. I would advocate for rounding toward the lesser value: (-1, 0) -> “-1” and (0,1) -> “0”

          • CanadaPlus@lemmy.sdf.org
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            7 months ago

            That could work. Calculating across eras would still end up sort of funny (the putative nativity would be a year closer to 233BC than 233AD, for example), but unless you’re an archeologist that doesn’t come up that often.

            I had another conversation about this not that long ago, and it really does boil down to treating intervals as numbers. Unix epoch doesn’t officially extend to pre-1970 years, but it’s defined as “the number of seconds that have elapsed [past perfect] since” for that reason, and does have a second 0. It fair to guess Bede himself didn’t properly distinguish between the two, because that leads directly to an argument 0 is a number, which AFAIK doesn’t appear in European mathematics until much later.

            • jsomae@lemmy.ml
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              7 months ago

              I think the only reason that the nativity would be a year closer to 233 ad than 233 bc is because Jesus was born in late December. Had he been born a week later on the 1st of January, it would work out, with 1 ad starting a year after his birth and 1 bc starting a year before (year 0 being that of his birth)

              • CanadaPlus@lemmy.sdf.org
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                7 months ago

                The year was built around it, not the other way. It’s all derived from the Christian calendar. I’m not sure off the top of my head how Christmas ended up a few days before New Years, but they’re deliberately very close. It has been argued that the real life birth might not have been in winter at all (or even Bethlehem).

                I digress, though. It would inevitably be lopsided somehow, because you’ve centered the numbering system around six months off of the New Years points.

      • jsomae@lemmy.ml
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        7 months ago

        floating point arithmetic on computers does suffer the existence of a negative zero. But it’s generally considered an unfortunate consequence of IEEE754.

      • CanadaPlus@lemmy.sdf.org
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        7 months ago

        Well, AD and BC(E) are the usual notation in this case, but yes. This is distinct from -0 and +0 in computation, because as OP says these are intervals rather than points.