Formed to be easy to use by centuries of laborers performing their work, beloved by all - verboten!
That must be why customary measurements are consistent across all cultures, since they are defined by use- hang on, I'm getting a call from the foot:
It varied in length from country to country, from city to city, and sometimes from trade to trade. Its length was usually between 250 mm and 335 mm and was generally, but not always, subdivided into 12 inches or 16 digits.
Boy I'm glad we use natural and not arbitrarily defined measurements!
I'm so glad we use a system based on Big Clive from Camden's shoe size on a gouty Tuesday in 1754 rather than a measure utterly unrelated to my life, like the speed of the thing I use to see literally everything I interact with.
Honestly I struggle to think of light traveling any distance shorter than from the sun to here, which I know is like 5 mins. I couldn't possibly begin to tell you how far it travels in a second, or a tenth of a second, or whatever.
A second is around the equator about seven and a half times. A tenth of a second is three quarters of the equator. The moon is about one and a quarter seconds away from earth, you know, if you ever wanna use it for something.
E: this is all half remembered from radio operation and radio astronomy. I could be wrong.
(that were based on useful lengths to work in, as determined by artisans through thousands of years of trial and error)
Source. Also fuck you this is a stupid statement. Why in the goddamn fuck would a variable unit with multiple "standardisations" almost exclusively based on the whims of contemporary rulers have been determined by artisans, and some specific length that was useful to them? If they're so specifically useful lengths and divisions to work with why are they variably divided into 9, 12, or 16 parts depending on where you are in the world and history, and why does the specifically useful length vary across standardisations? If the standardised size is so valuable to artists then why did it change twice in 200 years because different English kings wanted credit for it? You think their artisan friends were begging them to make the foot a little shorter?
that were based on universal constants that were selected by an aristocrat to look nice on paper
Did you do any thinking at all before writing this? Can you not come up with a single possible reason why it might be advantageous to base measurements off an immutable aspects of the universe instead of "dave reckon's this is a good length*? Is it really that hard to connect a desire for standardisation to something that actually is the same every time?
Ah, not quite - I'm operating on the assumption that the people working for thousands of years arbitrarily pulled them from thin air. Because, you know... That's literally how all definitions of measurement work. Try the cubit, somewhere between a foot and a half and 4 feet - what was so useful to people about those distances? At best ones like the foot and the chi came from using your forearm as a standard length, but once they're standardised the choice of whose forearm to use is completely arbitrary. Russian units were based on different ways of stretching your body parts - stuff like a hand span or arm span. Choosing what to use as a measurement is completely arbitrary, which then is standardised over time by people using the same thing as a measurement and it eventually getting defined as a single distance. The kings arbitrary choices were just building on the arbitrary choices of the past. There wasn't anything less arbitrary about the choice because lots of people used it.
Yes, they discovered the law as they understood it was mistaken, and so found more accurate ways to define it, which is why we're now using a fraction of a light second. If we find more precise definitions in future we'll define it by them.
Lastly, they already did that. The imperial and us customary measurement systems are both defined by metric distances now, specifically because metric distances, equally arbitrarily chosen as they are, shouldn't change. And if they do, we'll find something that doesn't.
You, a soyjak: Nooooooo, we should base our measurements on the body parts of an inbred king.
Them, another soyjak: Noooooo, we should base our measurements on what a bunch of out-of-touch scientists who never picked up a hammer thought was good.