This must be the most popular topic of conversation whenever a bunch of Europeans get together…
The U.S. adopted the English (I’m so rubbing it in) system of measures several hundred years ago and while the rest of the world (including Great Britain) moved on, going with the Metric system instead, we stuck with the good old pounds, inches, and ounces. As is the case whenever an entity used internationally lacks international standards, it’s been causing loads of confusion and even disasters. Besides asking why this is so (the United States is uniquely insular in this respect, even more than actual islands such as Japan or Great Britain where such a thing would have a natural justification), a lot of people engage in the oft time-consuming and fruitless rhetoric of which system is superior. I’m going to add to this hairball, but only a little bit. And I’ll try to use first principles rather than dogma (we’ll see if I succeed).
The goal of having a standard of units are to provide a common framework for the society to efficiently and robustly (i.e. in a way that’s resilient to errors) convey information about measures that doesn’t require special skills (i.e. to make the framework usable by as many people as possible).
I think there are two factors one must take into consideration when comparing the two systems: the intrinsic properties of the units (how practical they are in daily use) and the way they can be manipulated and composed (how to multiply them, compare them, convert them). I claim that the Imperial system is superior at the former, and the Metric system–at the latter.
What makes Imperial units intrinsically superior is the very choice of how much a primitive of various frequently uses measures actually measures. I think an inch is superior to a (centi)meter — I’m sure that if we were to take a survey of all lengths that humans refer to in their lives (controlling for a selection bias–people will tend to round up or down to the nearest unit of whatever system they are using), and draw a histogram of such usage, there would be a peak around the inch and not the (centi)meter. I’m even giving the Metric system the benefit of the uncertainty around which unit specifically should count as the primitive. In other words, we’re more likely to talk about things which are the size of an inch than things which are the size of a centimeter. Similarly, the (mili)liter is inferior to a fluid ounce — a fluid ounce is a more natural measure of a “splash” of a liquid.
There is a second-order effect of measures around, not at the primitive: do things more naturally come in (sub)harmonics of an inch (“half an inch”/”one-quarter of a pound”/”three ounces”) or the meter (“three centimeters”/”one-half of a liter”). This is probably much harder to determine. However, one important property of the Imperial system is that it operates primarily on natural and not decimal fractions of units. The Metric system talks about 0.2 centimeters; the Imperial system talks about one-eighth of an inch. Natural fractions are (even by the very definition) more engrained in the human nature than decimal fractions–we’re used to thinking about dividing things into equal parts and visualizing individual parts than dividing into a fixed number of parts (10) and visualizing multiples of that fraction.
The most important benefit of the Imperial system, in my view, is that it operates (mostly) on base 12 and not 10. I already wrote about how base 12 is far superior to base 10–it divides cleanly into 2, 3, 4 and 6. Base 10 numbers divide cleanly only into 2 and 5. Having intrinsically more divisors is better because it avoids awkward infinite fractions and, ultimately, inefficient communication.
When it comes to the second factor, though (how the units are manipulated and composed), the Metric system wins hands down. The Imperial system is inconsistent (12 inches to a foot; 16 ounces to a pound); there are far more units to remember (fluid ounce, pint, quart, gallon) and more units to remember the relationship between. The Imperial system captures many fewer measures at the very small and the very large range — in fact, the only way to represent very small or very large numbers is to use the multipliers that are the very foundation of the Metric system (10 million pounds, for example)!
Most of the disagreement, then (especially when a bunch of Europeans get together…), can be boiled down the the philosophical difference (I define a “philosophical difference” as a difference in opinions that cannot be reconciled with logic because it’s simply too costly to find a way to compare the opinions objectively) — do you prefer the intrinsic properties of the units (which I feel are more aligned with human nature), or the composition properties of the units (which are more aligned with civilization).
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“I’m sure that if we were to take a survey of all lengths that humans refer to in their lives (controlling for a selection bias–people will tend to round up or down to the nearest unit of whatever system they are using), and draw a histogram of such usage, there would be a peak around the inch and not the (centi)meter.” that sounds ameri-centric, and not at all based on first principles. show me an argument for why more things are actually the length of an inch rather than a centimeter and i’ll believe you.
moreover, the actual length of the unit can’t be arbitrary right? if you want to be. . .mildly functionalist (or even aristotelian about it) the metric system must have initially been based on some kind of naturally occurring length/volume/weight.
Hi, all I started a new Metric Petition I hope you all will sign, I need 50,000 people!
http://www.change.org/actions/view/twenty-first_century_metric_america
I wouldn’t call my argument ameri-centric… concretely, the inch was defined by the English, and also I’m not making any claims about the rationale behind the choice of an inch (the English may have simply gotten lucky).
I think you’re meaning to say that it’s arbitrary. Well, it certainly seems so–I lack the evidence (either empirical or theoretical) for why the histogram would look so and I am relying on my intuition. Now I thought about it harder, though, and here’s an outline of an argument: if you gave a caveman a stick one-centimeter long (or one-meter long), he would find it less useful than a stick one-inch long. Few things a caveman cares about are the size of a centimeter; the granularity is too much for the caveman to care.
Yes, every system is based on some kind of naturally occurring measure but you have to consider how direct this connection is. Incidentally, the inch may have been based on the size of the thumb (a good natural measuring device) while the metre was one-ten-millionth of the distance between the North Pole and a point on the Equator. Yes, both are based on natural lengths but it’s hard to visualize (or come by) one-ten-milionth of the distance between two points on the surface of the Earth; we all have thumbs handy though.
As a 51-year-old Australian, I am exceedingly pleased that Australia converted to metric 30 years ago. It is a much simpler and efficient system. I was brought up with imperial in the 1960s and 70s; but after full metric conversion, I made the effort to learn metric and think in it, and I’m very glad I did. Being based on 10, 100, and 1000 makes metric a very flexible system. While imperial/customary units based on 12, such as the foot, may be evenly divisible by 2, 3, 4, and 6, 1000, as the product of 10 cubed, is evenly divisible by 2, 4, 5, 8, 10, 20, 25, 40, 50, 100, 125, 200, 250, and 500. Hands down metric units are better, more practical, and more utilitarian weights and measures than imperial/customary units.
I am still hopeful that the U.S. can do it; I think that the perceived short-term costs are far outweighed by the long-term benefits (even if it’s to avoid things like this).
The metric momentum is certainly good and essential news for the US – we can thank our good friends the American youth for this. They have learned via blogs, Twitter and Facebook chats around the world, that they have been conned for so many years that the US is the only country that matters and the whole world should use the inch-pound system because it is so much easier to use, i.e it’s MUCH easier to multiply 11 and 19/16 of an inch by one foot, and 9 inches and seven eighths of an inch than it is to multiply 300 by 455 mm.
Who said the dinosaurs were extinct, anyway? Wasn’t Sarah Palin, was it??
Welcome to 96 percent of the world, America – you’ll enjoy it as much as we do.
Just a PS – Centimetres aren’t used today, it’s all in MILLIMETRES.
Neither is the word Kilogram – it’s ‘kilo’.
Also you should be using ‘Celsius’, not ‘Centigrade’
All through my years of going to school I could never understand why the US still uses such a bad system of measurement. The metric system is so much easier to use yet our leaders still force us to us a system that doesn’t make any sense mathematically. Alas, while it does appear we have some momentum to move to the metric system, it doesn’t seem like we’ll be there any time soon. Until then, I created a site that can help those who need complex conversions done in an easy and timely manner. An easy to use Hyperlink measurement converter for all the major measurements used in the US and metric system.