4 ms·

Of course, the meter was originally based on the shape of the earth as well - the distance from the pole to the equator was defined as 10 Mm in 1793. As far as

Of course, the meter was originally based on the shape of the earth as well - the distance from the pole to the equator was defined as 10 Mm in 1793. As far as the US unit tragedy goes, I think it's important to remember that SI units are full of compromises in exactly the same way that US units are, because they need to accommodate practical, human scale concerns. For example, degrees Celsius is a ridiculous concept from a scientific point of view (ask any beginning chemistry student who just messed up their test because they forgot to convert to Celsius to Kelvin before applying PV=nRT). If you believe the point of a unit system is to be useful for science, it's hard to defend a unit where 0 doesn't actually mean 0, since it introduces all sorts of confusion in the same way as traditional units do. And why does the whole world still measure days with 24 hours in them, each with 60 minutes, each with 60 seconds? Because decimal time (although France tried to impose it during the transition to SI units) is just too darn inconvenient for humans to use. The failure of decimal time shows why humans prefer non-decimal units: because the resulting units are human-scale. Converting from seconds to hours or days is not as easy as multiplying by 1000, but kiloseconds is an inconvenient unit - too short for an hour, while 100 kiloseconds is significantly longer than a day. Somehow the metric world manages these conversions just fine (in the same way the US manages conversions between inches, feet and yards). The traditional units evolved over hundreds of years, and I'm glad the US keeps them around - like nautical miles, they are quite useful.

seszett 10y ago
> The failure of decimal time shows why humans prefer non-decimal units: because the resulting units are human-scale. I really don't agree though. The failure of revolutionary France to switch to decimal time like it switched to decimal units, is that time was already well standardised back then, while a single standard of decimal units was a real improvement over the mess of local units that was in use before. I think you're making the same mistake every argument against metric always makes: "inches are more convenient than centimeters, because otherwise how can we call 19" racks!". Well otherwise, racks would be 50 centimeters and not 19". The same way, people would work just fine with 10-hour days, 100-minute hours and 100-second minutes. Maybe people would use half-hours more often than today to divide the day, but I can assure you that it would just work as conveniently. There is nothing inherently natural in dividing the day in 24/60/60 parts, we're just used to it. Also, if you have ever worked with time keeping software (or worse, hardware) you would know the metric world actually doesn't manage these conversions just fine.
- ChoHag 10y ago
  The reason decimal time did and always will fail is that no matter how you slice it, 365.24ish is not divisible by 10. Moreover there is nothing inherently natural about 10 as a base. Like many of our modern conveniences it is entirely arbitrary and about the worst possible option. Fin
  - seszett 10y ago
    > The reason decimal time did and always will fail is that no matter how you slice it, 365.24ish is not divisible by 10. It's not divisible by 60 or 24 either, so I don't see the point. Decimal time only deals with units from the day down. Decimal calendar deals with days, weeks, months and years. Its adoption went far better than decimal time. > Moreover there is nothing inherently natural about 10 as a base. No base is inherently natural, 60 certainly isn't. 10 just happens to be the one we use as a standard.
    - ChoHag 10y ago
      That is the point. There is no way to cleanly divide up the time taken by the earth's orbit by the time taken by the earth's rotation. They are simply incompatible. It is impossible to say objectively that any one scheme is better than another, with one exception: the current scheme is always better than all the others by virtue of being current. And consider this: Leap seconds are a thing.
      - Dylan16807 10y ago
        Your point about years is completely irrelevant to how you divide a day into hours, minutes, and seconds, which is what 'decimal time' talks about.
        ChoHag 10y ago
        The advantage of decimalisation is the geometric expansion it engenders which cannot happen because the year is not 10, 100, 1000 or any other multiple of 10 days. It is not an integer multiple of anything days. It is evidence that no matter how much we try and break the universe up into nice coherent chunks, the universe has other ideas. Fighting reality will fail. The advantage to breaking up the day into units less than 1 day is the factorisation that can be applied. 24 factors much better than 10. Pretty much everything factors much better than 10. There is no advantage to decimalising the day except to give basement-dwellers a boner.

seszett 10y ago

> The failure of decimal time shows why humans prefer non-decimal units: because the resulting units are human-scale. I really don't agree though. The failure of revolutionary France to switch to decimal time like it switched to decimal units, is that time was already well standardised back then, while a single standard of decimal units was a real improvement over the mess of local units that was in use before. I think you're making the same mistake every argument against metric always makes: "inches are more convenient than centimeters, because otherwise how can we call 19" racks!". Well otherwise, racks would be 50 centimeters and not 19". The same way, people would work just fine with 10-hour days, 100-minute hours and 100-second minutes. Maybe people would use half-hours more often than today to divide the day, but I can assure you that it would just work as conveniently. There is nothing inherently natural in dividing the day in 24/60/60 parts, we're just used to it. Also, if you have ever worked with time keeping software (or worse, hardware) you would know the metric world actually doesn't manage these conversions just fine.

ChoHag 10y ago
The reason decimal time did and always will fail is that no matter how you slice it, 365.24ish is not divisible by 10. Moreover there is nothing inherently natural about 10 as a base. Like many of our modern conveniences it is entirely arbitrary and about the worst possible option. Fin
- seszett 10y ago
  > The reason decimal time did and always will fail is that no matter how you slice it, 365.24ish is not divisible by 10. It's not divisible by 60 or 24 either, so I don't see the point. Decimal time only deals with units from the day down. Decimal calendar deals with days, weeks, months and years. Its adoption went far better than decimal time. > Moreover there is nothing inherently natural about 10 as a base. No base is inherently natural, 60 certainly isn't. 10 just happens to be the one we use as a standard.
  - ChoHag 10y ago
    That is the point. There is no way to cleanly divide up the time taken by the earth's orbit by the time taken by the earth's rotation. They are simply incompatible. It is impossible to say objectively that any one scheme is better than another, with one exception: the current scheme is always better than all the others by virtue of being current. And consider this: Leap seconds are a thing.
    - Dylan16807 10y ago
      Your point about years is completely irrelevant to how you divide a day into hours, minutes, and seconds, which is what 'decimal time' talks about.
      - ChoHag 10y ago
        The advantage of decimalisation is the geometric expansion it engenders which cannot happen because the year is not 10, 100, 1000 or any other multiple of 10 days. It is not an integer multiple of anything days. It is evidence that no matter how much we try and break the universe up into nice coherent chunks, the universe has other ideas. Fighting reality will fail. The advantage to breaking up the day into units less than 1 day is the factorisation that can be applied. 24 factors much better than 10. Pretty much everything factors much better than 10. There is no advantage to decimalising the day except to give basement-dwellers a boner.