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I think dividing by 10 is much more useful than the author admits and better than dividing by 2. It's a fine starting point. I realize the author isn't necessar

I think dividing by 10 is much more useful than the author admits and better than dividing by 2. It's a fine starting point. I realize the author isn't necessarily explicitly defending the Imperial system that strongly, but 2 by itself is a big meh. E.g. even in the parts of the Imperial system that use 2 as a main factor (1", half inch, quarter inch, etc for small measurements) you end up with a bunch of stuff like "take 1/16th off of 3/4ths" that is less obvious than something like "take a millimeter and a half off of 19mm" when you're dealing with a base-10 number system. (Even before taking into account the conversion to feet that isn't a power-of-two based one, but is instead a factor of 12.) Two just isn't a big enough divisor, ten works much better as a "step change" interval. A measurement system that was uniformly 8 or 12 or 16 could avoid that problem by having equivalent steps to mm, cm, meter, etc. but still runs into the problem of having to change the entire number system too which is rather not the fault of the metric system in the first place.

timbit42 3y ago
Dividing by 10 is much more useful because you are using base 10. If you were using base 12, then dividing by 12 would be much more useful.
mlhpdx 3y ago
Yep, particularly when counting fingers. That in mind, I wonder why base 5 wasn’t a thing since it would have been easier to keep track of the “digits” up to 25.
jprete 3y ago
Dividing by two has one very significant advantage - the brain is equipped to directly compare two lengths, so a division by two is easy to eyeball and get roughly correct. That's probably also why music is almost always spaced using powers of two, with potentially a single three or occasionally a five - the brain can easily track and measure equal divisions.
- majormajor 3y ago
  I think that makes a lot of sense in music or other "divide this up" tasks that don't require concrete objects but that's not most of what the metric system deals with. And time isn't decimal-based at the larger-than-one-second level, after all. But in the world of concrete objects "eyeball this into two pieces" is much less useful and less common than "ok so we need to account for the extra 3mm of this extra piece so add that to the 44mm base measurement" - which is much more straightforward than something like "add 3/32nds to 1 and 3/4 inches." especially if you don't know that you're gonna end up with a measurement in the 32nds when you make the first measurement. Or larger-scale like "we went six hundred feet already, we needed to go a mile and a half, how much is left?"

timbit42 3y ago

Dividing by 10 is much more useful because you are using base 10. If you were using base 12, then dividing by 12 would be much more useful.

mlhpdx 3y ago

Yep, particularly when counting fingers. That in mind, I wonder why base 5 wasn’t a thing since it would have been easier to keep track of the “digits” up to 25.

jprete 3y ago

Dividing by two has one very significant advantage - the brain is equipped to directly compare two lengths, so a division by two is easy to eyeball and get roughly correct. That's probably also why music is almost always spaced using powers of two, with potentially a single three or occasionally a five - the brain can easily track and measure equal divisions.

majormajor 3y ago
I think that makes a lot of sense in music or other "divide this up" tasks that don't require concrete objects but that's not most of what the metric system deals with. And time isn't decimal-based at the larger-than-one-second level, after all. But in the world of concrete objects "eyeball this into two pieces" is much less useful and less common than "ok so we need to account for the extra 3mm of this extra piece so add that to the 44mm base measurement" - which is much more straightforward than something like "add 3/32nds to 1 and 3/4 inches." especially if you don't know that you're gonna end up with a measurement in the 32nds when you make the first measurement. Or larger-scale like "we went six hundred feet already, we needed to go a mile and a half, how much is left?"