Authoritarian Measures?

Kim Du Toit is no fan of the metric system. He wrote that the metric system is authoritarian, because it sets arbitrary objects (a mass of metal and a length between two incisions) as fundamental units.

Leaving aside the fact that the definition of units is a tad more complex than that (here's a comprehensive list of units of measurement) and their history can be quite convoluted, it is necessary for units of measurement to be both arbitrary (to a degree) and imposed by an authority.

I suppose that humans understood the need for standard units (of mass and length, but probably also time) soon after commerce was introduced. Because commerce between buyes and sellers that can't agree on measurement units would just degenerate into useless chaos and quarrels. Even if the different parties can not or want not to adopt common units, they would still need their own standard units so that accurate conversions can be worked out.

But how can standard units be defined? Here is where some level of arbitrariety is required. The size of limbs varies sensibly from one person to the other, and seeds of the same plant (often used as mass units) become bigger or smaller with location and time. In the end it is necessary to take a certain value for an unit and declare it to be the standard, even if the most popular value is different. This is exactly what king Henry I did in the 12^th century with the yard - so much for the meter being authoritarian.

I can concede that some metric units are more arbitrary than others (loosely) based on natural quantities, but to me that is just splitting hairs, frankly.

Then, an authority is required to vigilate that the standards are not tampered with or damaged, and that the units used in commerce and trade - either because of mistakes and errors, or malice - do not stray too far away from the standards. Without such vigilance, chaos is bound to return.

Now, we can discuss on which scale the standardization should occur, but anything smaller than national scale is in my opinion exceedingly impractical nowadays. The standardization scale is determined by practical needs - mainly, of commerce and trade, so it is by no means fixed. By the way, the US yard is defined on the basis of the meter since 1893.

I also think that if a group of people can agree on measurement units to use between themselves, they should be able to do it without government interference. However, when they want to relate with the government or the public at large, the must adopt the standard units.