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

  • jsomae@lemmy.ml
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    7 months ago

    This explanation is unclear to me. Why do we choose the later of the two endpoints of the year for (0, 1) but the earlier of the two for (-1, 0)?

    • Reil@beehaw.org
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      7 months ago

      The language is rooted in the same logic as people. Your first year was between the ages of 0 and 1. The first year before you were born is between -1 and 0. There is no 0th year because 0 is a point in time and not a range in time.

      • jsomae@lemmy.ml
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        7 months ago

        Your explanation works equally well for any integer though. You could say the same of 1.

        I think you’re saying that it’s a fencepost issue. But even for personal ages this doesn’t check out: for a year after you are born, your age is “0.” A one-year-old baby is in the following year.

        • Reil@beehaw.org
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          7 months ago

          I feel you’ve missed the point I was making and assumed I’ve made another. Age number and year number are different. You’re in your first year when your age is not yet 1. You’re in your second year when your age is between 1 and 2.

          Years follow numbers as in "this year was the first/second/third year of ", not “this year was the year turned X years old”

          • jsomae@lemmy.ml
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            7 months ago

            Oh I see. Sure, historically it makes sense that years have been ordinal numbers. But in the modern era with all our math and computational knowledge, it is not convenient anymore. It means off-by-one errors are easy to commit when comparing BC and AD years.

            This is why programming languages all index from 0 rather than 1 (knuth and lua be damned)

    • Rivalarrival@lemmy.today
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      7 months ago

      Absolute value. Both systems count time from the same epoch, or zero point.

      One year before the epoch is 1 January 1BCE One year after the epoch is 31 December, 1CE.

      Half a year before the epoch (-0.5 years) is June 30, 1BCE. Half a year after the epoch (0.5 years) is July 1st, 1CE. These dates occur within the first year before the epoch, and the first year after the epoch, respectively.

    • GlendatheGayWitch@lemmy.world
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      7 months ago

      Remember originally that -1 was 1 BC, meaning 1 year before the birth of christ. The negative numbers are measuring the distance away from 0.

      Edit: in the positive direction, the 1 was 1 AD, meaning the first year of our lord. Just like when talking about the reign of kings/queens, the first year of their reign is 1 and the 14th year that they reigned is 14. I believe the timekeeping for Ages in LOTR may also be similar.