House of Eratosthenes

Not that it doesn’t have its uses. If I’m calculating the accumulation of kinetic energy in an accelerating mass, and the capacity of that kinetic energy when it’s converted into something else, the metric system would be my first choice.

It is the advocacy for the metric system that cheeses me off. The idiotic arguments. “Ten is sensible”; that right there, that’s it. No, ding-dong, ten is not sensible. What is two-thirds of ten? You want to build a house that way?

See, for guys who have hammer-loops in their jeans that they use to actually hold hammers, and carry a tape measure clipped to their belts, twelve is better. It’s better for actually building things. Twelve is a composite that is the product of a low prime times the square of an even lower prime. Ten is just two primes, great for multiplying but lousy for dividing.

And why do you want a number great-for-multiplying anyway? That’s just for doing math in your head, or on a sheet of paper. There’s computers everywhere, you goth vegan Canuck black-turtleneck-wearing atheist who probably thinks the European Union is the greatest thing since the printing press. We don’t need number systems that are great for multiplying. Great-for-multiplying is for lazy students who are still in class and want an easy A without bothering to switch their iPhones out of Angry Birds. Great-for-dividing is what people need when they’re designing or building something that is actually supposed to work. And the problem you run into with that, when you’re trying to divide ten by three, is not something that will trip you up until you have invested some actual time. Real time, out in the real world, building real things.

The ten-is-easier argument is just stupid. Worse than stupid, it is a successful inversion; it is the winning of an argument based on the aesthetics of the argument, without respect to the actual substance, or its ramifications for the rest of us out here where objects actually move around and have an effect on one another. The impression left is that the English system is based on yesteryear, specifically the distance between Henry I of England’s nose and his thumb, and the tens-system is the world of tomorrow. The truth is the opposite of this. Most people don’t have much call to do math with newtons and km/sec^2. And they haven’t got a frequent need to do math in their heads merely by moving a decimal point around. We’re spending our lives in front of computers. Imposing a whole new system on oldsters who just want to buy medicine and margarine, just so kids can get their math homework done a little quicker when they’re too lazy to enter numbers into a calculator, has turned out to be a relic of the 1970’s.

Great post. I couldn’t agree more, though until I read your post I couldn’t have told you exactly why. This is great ammo for arguing the metric system proponents.
- Frank the Wanderer | 05/01/2014 @ 07:37
For those interested there is a truly delightful book written by an engineer titled: Metric Madness that is still in print. Author is J.W. Batcheler, published 1981, ISBN: 0-8159-6219-3. Amazon lists it in paperback @ $6.00:
http://www.amazon.com/Metric-Madness-Reasons-Converting-System/dp/0815962193
Dan Kurt
- Dan Kurt | 05/01/2014 @ 08:37
The situation with units is much more complex than people imagine. Metric vs. customary doesn’t come close to the real world situation.

When I was an undergraduate engineering student, we were taught seven systems of units:

(1) customary UK/US; pound-mass, pound-force, foot, second, Farenheit, Rankine, Btu plus the “metric” electrical units, plus foot-candles, plus traditional volume (pecks, bushels, gallons) and surveying units (rods, acres); this is a gravitational system. F = ma/gc

(2) slug (mass), pound force, foot, second etc (all the other customary units); this is an absolute system. F = ma

(3) pound mass, poundal (force), foot, second, etc (all the other customary units; this is an absolute system. F = ma

(4) the cps system: gram, dyne, erg, centimeter, liter, second, calory, etc; a precursor to SI and an absolute system. A very convenient system for lab chemists and biologist who continue to use it; also doctors use a version of it. F = ma

(5) the metric system: kilogram, newton, meter, second, joule, liter, etc.; the immediate precursor to SI; an absolute system. F = ma

(6) Systeme Internationale, SI, the modern metric system, kilogram, newton, meter, second, joule, etc; differs from the metric system in the definition of the electrical, light and radiation units; an absolute system. F = ma

(7) European engineering metric system: kilogram-mass, kilogram-force, meter second, etc.; a gravitional system; essentially parallels the customary US/UK system. Even European engineers hate SI. F = ma/gc

We needed to know seven different systems of units because were and most are still in use. Chemical engineers still think in terms of pound-mass per hour. And the are existing structures, machine and products designed in currently unused systems.

In case you think it’s unimportant, NASA “scientists” crashed two Mars probes into the planets because they thought the rocket engines were rated in newtons or thrust, whereas the manufacturers rated them in pounds-force of thrust. 1 lbf = 4.45 N.

Even more fun. The US is by law a metric country. We were among the founders of the original metric system (cps) and all the customary units are defined in terms of the metric master units: e.g., 1 lb-mass = 454 g; 1 ft = 30.48 cm, 1 lb-force = 4.45 N, etc.
- Bob Sykes | 05/01/2014 @ 11:20
F = magic is right. P_Ang’s head hot. Brain hurtz.
- P_Ang | 05/01/2014 @ 13:09
Metric Math Mistake Muffed Mars Meteorology Mission
http://www.wired.com/2010/11/1110mars-climate-observer-report/
- Zachriel | 05/02/2014 @ 09:08
Yet another costly mistake brought to us by the problematic thinking of modern liberalism.
- mkfreeberg | 05/02/2014 @ 19:23
This is the FIRST TIME I have heard this incredibly rational argument for the imperial system over the metric! Thank you!
- rhjunior | 05/03/2014 @ 13:43
[…] easy multiplication has had many practical impacts. For that reason, M.K. Freeberg from the blog House of Eratosthenes recently called the Metric System “yet another costly mistake brought to us by the […]
- Is the Metric System Really a Stupid Idea After All? | For God, Family, and Country | 05/09/2014 @ 03:24
I agree that the metric system is great for doing calculations in physics and engineering. I had to learn both SI and English, and I much prefer SI.

As for the metric system being lousy for “building things”, it depends. The English system is great for getting a feel for how something will turn out — we Americans are used to thinking in terms of English units, so we can more easily envision an acre than a hectare, or a gallon than a liter, etc., etc.

But I think the argument that SI is lousy for building things based on difficulties in division is largely bogus. If you’re a carpenter, say, and you have a 29-inch piece of wood you have to cut up into thirds, the math gets ugly, at least if you’re trying to do it in your head. 29 divided by 3 = 9.67 inches (before allowing for the saw kerf), and the 0.67 gets a bit tough, depending on the level of precision required — do you call it 11/16″ or 21/32″?

In SI, 29 inches works out to 73.7 centimeters. 73.7 divided by isn’t necessarily easy, but who cares? “Downshift” to 737 millimeters, divide by 3, and get 246 millimeters (again, before allowing for the saw kerf). Yeah, there’s a fraction-of-a-millimeter error in there, but I don’t think the average carpenter is going to worry about a error on the order of 0.020″. No need to worry about getting cross-eyed looking at your English ruler, making sure you have your sixteenths and thirty-seconds straight — you just take your metric ruler, count off 24 centimeters, and then six millimeters, and you’re done.

My two cents’ worth.

Hale Adams
Pikesville, People’s Democratic Republic of Maryland
- Hale Adams | 05/11/2014 @ 07:07
Those are good points, but by the time my calculations have to deal with saw kerf, I’m usually using a calculator anyway. Once again, I’m left to wonder: Isn’t that how everybody else is doing it? If the linear measurements deal with bigger things, and equations in which saw kerf is no longer a consideration, you’re almost certainly dealing with feet or yards. Dividing by 7 remains a challenge, but the rest mostly works itself out.

The real difference being discussed here has to do with a measurement system based on an ideal numerator, versus one based on an idea denominator. What the metric-zealots often miss is, there are situations in which the former is entirely irrelevant and the latter is highly preferable. Especially when you’re conceiving a new design for something that is to fit into an arbitrary, contained space.

Point is: Because of these considerations, historically, the English system has been responsible for getting a lot of stuff built. Fences, houses on property, railroads, etc. There are reasons for this, and a lot of them have to do with advantages of the English system over SI, which tend to be overlooked by those who enthuse to excess over the Next Big Revolutionary Change^TM.
- mkfreeberg | 05/11/2014 @ 07:24

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Metric SystemThursday, May 1st, 2014

Metric System
Thursday, May 1st, 2014