> Either way, people tend to value tradition more than progress or rationalisation.
Don't get me wrong, I'm pro-metric, but the old units are not entirely irrational.
For instance, there are 12 inches in a foot, which may seem odd, unless you need to measure 1/3 of a foot. You might argue that the foot represents a future society that uses base-12, while metric lags behind, in the not-as-divisible base-10 world.
It's also interesting to note that on rulers, in the US anyway, each inch is subdivided into 16 sub-units, so measurements are usually given as, say, 3 3/16 inches rather than 3.1875 or (rounding) 3.2 inches. In other words, hexadecimal rather than decimal.
So, 12 inches in a foot isn't odd because it makes it easier to measure a third of a foot, but, apparently, people need one eighth or one sixteenth of an inch way more often than one third, so the rational thing to do is to divide an inch in 16 parts, not 12?
Also, people rarely need a third of a mile, so why bother giving that a name or even making that an integral number of yards? But hey, if you happen to need one eleventh of a mile, rejoice: that's 160 yards, and one eighth of a mile, apparently, is used so much that it has its own name.
Correlation is not causation, but chances are a third of a foot is more popular because there are 12 inches in a foot, not the other way around.
Imperial units would be a lot more defensible if they were consistent. But just in your example we've got things being divided into 12 and 16 parts, and many other random divisors are common. I'd be onboard with a system of units where the divisor is always constant, but having it random is annoying. Fortunately there is a system of units where the divisor is always constant - SI! Yeah, it's 10 instead of 12, but it'll have to do.
I agree that the Imperial system is a mess. 5,280 feet in a mile?
But my point is that people who prefer old units are not being entirely irrational, or averse to change.
It's just that for their particular use case (making human-scale furniture out of wood, for example), the Imperial system works pretty well, and perhaps better than the base-10 metric system.
If they had to spend their days converting between acres and square feet (43,560 of the latter go into the former, by the way), they might be more inclined to switch to metric.
One thousand paces in a mile, where each pace is two steps.
A property of the US customary units is they tend to be more optimized for specific uses at a given scales, with little thought given to changing scales. Metric units make conversion easier, at the cost of often less suitable for use at scale - how many steps does it take to go a kilometer?
Unless you're in a military unit that is on the march, what does the number of steps in a kilometer matter for at all? And there is a huge natural variation in human stride length anyway -- you won't be surprised to know that the figure you mentioned for miles is an average that only applies for adult males of military height (i.e. not even shorter men). I think SI units are great for measuring distance at scale. Nanometers, micrometers, millimeters, centimeters, meters, and kilometers are all in common usage, and can represent pretty much anything you'd need. By contrast, it's imperial that has the real problems with use at scale, specifically down at tiny scales.