Why exactly couldn’t you specify half a meter, or a third of a meter, or a sixth of a meter, if you wanted to? The point is that every unit in the customary system was picked arbitrarily. An inch had nothing to do with a foot, a foot had nothing to do with a yard, a yard had nothing to do with a mile, a pound and the various ounces were created by different people for different uses, and were never intermixed. Bushel, pecks, hogsheads, acres, furlongs, fathoms, rods, grains, stones, all were invented without a thought for interconverting.
That worked all right back in medieval times. No one cared how many ounces were in a bushel, the question never came up.
But now we are living in an age of science and engineering. 5280 feet per mile? What in god’s name is that? The answer is that they just measured a mile, and measured a foot, and figured out that the traditional foot and the traditional mile had that conversion factor.
But of course, this makes no sense. There should be one unit of length, one unit of volume, one unit of mass, etc. And the pro-traditionalists are correct that the unit we choose is completely arbitrary. It would make just as much sense to choose the inch or the foot as the basic unit of length rather than the meter. That is, IF we were starting over and generating a system from scratch. But it turns out that there is already a system in place that a lot of people around the world are using, that already has these basic units picked out. Since the basic units are arbitrary, it would be much easier just to use the same unit that everyone else uses.
And it would only be more easy to use base-12 measuring systems if we used a base-12 numbering system. Sure, a base-12 numbering system presents some advantages. However, our current system of arabic numbers has been in use for hundreds of years and works very well…the advantages of base-12 or base-16 or base-2 are pretty subtle. Since we are not going to start over with a new number system based on dozens, we are stuck with arabic numbers and base-10. Given that, decimal units for our measuring system make the most sense, since it makes math much easier.
Now, measurement of time is a problem. The trouble is that we have several natural units of time…the day, the year, and the month…but none are interconvertible since they have no essential relationship with each other. We could pick a natural unit as our base unit of time, but there’s no real reason to do that. And anyway, once we are talking about getting off this planet there’s no reason to stick with earth’s astronomy anyway. So we already have a unit of time called the second. The exact length of the second is unimportant, just that it has a particular length. So we choose the second as our fundamental unit of time.
So we are agreed on a decimal measuring system. We are agreed that the units are arbitrary. So then the currently-in-use metric system becomes the overwhelmingly superior choice.
If we were starting over, we might teach our children binary or dozens or base-30 (123*5) number systems. We might choose as our fundemental units something else, depending on our predjudices…say planck length, or the vibration of a hydrogen nucleus. But even if we chose some units that were fundamental in some ways, in most everyday uses that wouldn’t make a difference. Most of the time they’d seem pretty arbitrary. And therefore only slightly superior to our already existing measuring scheme, the metric system.
Bottom line, metric rules, traditional drools.
