> That the metric system is just as arbitrary as the customary units No-one claims it isn't arbitrary. Any choice of units is arbitrary. "Not being arbitrary"

> That the metric system is just as arbitrary as the customary units No-one claims it isn't arbitrary. Any choice of units is arbitrary. "Not being arbitrary" just isn't a desideratum when considering what makes a good system of units. The main desirable property is coherence [0], which SI has. But I don't think anyone would claim SI is perfect. It's not; it's got at least a couple of warts. One is that "kg" is a base unit and is prefixed. But that's about the worst of it. CGS is also coherent, but has a similar problem with a prefixed base unit (in this case, cm). US Customary units is not only incoherent, but does things like conflate mass and force (lb is a technically a measure of force, so is the long/short ton, and slug is the proper unit for mass) and has far too many derived units that measure the same thing (e.g. ft lb/s, hp and BTU/h, vs just W). [0]: https://en.wikipedia.org/wiki/Coherence_(units_of_measurement) https://en.wikipedia.org/wiki/Coherence_(units_of_measuremen...