…because you think the metric system is logical

Posted on May 7, 2009


300px-French_Revolution_GuillotineWe know the metric system is logical. We know it’s logical for the same reason we know Paris Hilton is famous: because that’s what people keep telling us. Of course, when enough people tell you that someone is famous, it becomes true by definition. Logic, however, operates under different rules, and simply declaring something logical doesn’t make it so, even if the declaration is coming from millions of people.

Unless they’re French.

The French love logic. If the French found logic living on a street corner with a hand-made sign saying, “Will Q.E.D. for food,” they’d take it home, feed it, and buy it a whole new set of clothes. But while there’s no question the French love logic, they do so the same way ducks love water: paddle around in it all day, then just let it roll right off their backs.

Take the French Revolution. Under the banner of rationalism, French citizens rose up against their royal oppressors and instituted a new era of reason and enlightenment: the first order of which was to kill off a goodly portion of those who had taken part in the revolution.

The second order was to turn everything into ten.

The metric system, with which the world’s more sheep-like populace is so enamoured, was just one of many decimal systems instituted by the French following their Revolution. Under the new enlightenment, a minute had 100 seconds, an hour had 100 minutes, and a day had ten hours. The 12 months of the year gave way to ten months, into which  the days were equally divided — as much as possible, that is. With the year continuing to have 365 days (no matter how often the revolutionaries threatened to have it guillotined if it didn’t behave more logically), trying to evenly distribute the days into 10 months was a bit problematic. The leap year also proved difficult and, due to a clerical error, never did get fully worked out. (I’m not making this up.) A short 12 years later (note: not ten) the whole thing was dropped and everyone went back to 24 hour days and 12 month years.

The only thing that lasted was their system of measurement.

The foundation of the metric system is the meter, which, by merest coincidence (involving hundreds of hours of careful calculations), happens to be almost the same length as the provenly useful yard, which was roughly equivalent to the distance between an average person’s nose and the end of his outstretched arm. To the French, this was a wholly illogical criterion and in the name of rationality they defined their meter as one ten-millionth of the distance from the equator to the north pole (as measured through Paris). Of course, back then science was still in it’s infancy, and the definition has since been replaced with one conforming even more closely to French logic: the distance light travels in one 299,792,458th of a second.

I’m saying — rolls right off their backs.

From the meter, everything is a matter of division or multiplication by tens. The next unit smaller than a meter is the centimeter, which is about half an inch, and the next unit larger is the kilometer, or roughly the length of ten football fields. The Imperial System, on the other hand, has no set number of units determining when one measurement becomes another. Its sole criterion is usefulness. The basic unit of the yard is divided into three feet, and the foot into 12 inches. As we move to to larger units we have the furlong (220 yards), the mile (eight furlongs), and the league (three miles). While this proves remarkably handy in human terms, giving us an appropriate unit of measurement for each situation, it is anathema to French logic.

During the course of their plunge into logic, the one thing the French never appeared to ask themselves was why 12 had come to play such a pervasive role in measurement to begin with. After all, we have ten fingers and ten toes. Where did 12 come from?

The answer, as anyone schooled in math could have told them, is that base 12 (also called the “duodecimal system) is pretty well the perfect number for fractions. While 10 can only be evenly divided by 2 and 5, the number 12 can be evenly divided by 2, 3, 4, and 6. And since all measurements of length in the Imperial System involve the foot (12 inches, remember?), cutting or dividing things into halves, thirds, fourths, and sixths never results in irrational numbers.

And to those who complain that they’ve never known how many gallons are in a hogshead, or other obscure units, that’s because you don’t have to. For some industries, however, these “obscure” units are surprisingly handy.

As for that easy conversion from one unit to the next so vociferously promoted by metric enthusiasts? You know, where all you have to do is move the decimal point to go from, say, centimeters to meters or grams to kilograms? Turns out that misplacing the decimal point is one of the most common mistakes people make in mathematical operations. In Canada we’ve been metric since the ’70s. Here’s a typical conversation I have with the clerks behind the meat and cheese counters — clerks who are in their late teens, early twenties, and have never been exposed to anything but metric.

“That’s 1.2 kilograms.”
“Do you happen to know what that is in grams?” I ask innocently. (The answer is 1,200 grams.)
“Oh, uh. That would be 120 grams.”
“You sure?” I ask dubiously.
“Um. No, wait. It’s 12 grams.”
“Ah! Thanks. The metric system certainly is a lot easier than Imperial, isn’t it?”
“Margarine is in the dairy section.”