Yes, it’s from a book called “Uncle John’s Bathroom Reader” and that book was resting on a closed toilet seat in a nation that only kind of uses the metric system in certain situations… however, you’d be surprised how much you can learn after a single visit to any local fast-food joint!
All measurements are arbitrary. This feels like that Fahrenheit debate where “60 feels natural for room temperature” as if anyone has any idea what number a room should be. A meter is just a chunk of distance about this size (holds hands apart). There’s nothing a foot can add to a measurement that a meter can’t. You’ll need fractions and smaller or bigger units in all real world cases anyway, so having easy conversions is much more useful than a “natural” base unit.
Perhaps in a perfectly rational world, but humans are silly creatures. The human brain evolved to deal with small numbers. Distinguishing one vs two lions is important, but distinguishing 14 vs 15 lions is not, so our brain immediately recognises numbers up to about six and has to rely on conscious counting for anything larger. If I told you that “This dog is two ducks tall” you’d have a pretty good idea of how big the dog is, but if I said it was “20 mice tall” you might have trouble visualising, or worse “450 ants tall” at which point I would have no idea. Our brains don’t innately have the ability to accurately conceptualise large numbers, which is why the metric prefix system works so well - it keeps numbers relatively small. I think the same logic applies to decimals and fractions. Simple fractions like halves through to perhaps fifths can be visually conceptualised at a glance, but beyond that it requires calculation.
What that means to me is that ideally your measurement unit should be big enough to be able to measure most things you deal with on a daily basis using no more than say 10 units (arbitrary, I could be persuaded down to 6 or up to 20), and still measuring most things without going smaller than about 0.2 units. As an example, consider human height (after all, what could be more a more human measurement?). The average person is between 1.5 and 1.9m tall, which is not a great start since we’re riding close to the 0.2 ‘lower resolution’ just describing the whole range. You could use centimetres but then you’re looking at 150 or 190 which is much too large to visualise nicely. Decimetres is better but not great. Feet is a pretty good fit for this, since that’d be about 4.9 to 6.2 ft. We haven’t violated either the max or minimum requirements and we still have a decent resolution within the range too.
I agree, but my whole point is that we didn’t have to choose!
Hey! Didn’t you just violate your own rule of “0.2 lower resolution”?
You’re right about big numbers losing relevance in our minds, but I don’t think that’s even true for units of measurement. Since all units are arbitrary, they are inherently linked to a mental model with simple maths, quick conversions and rules of thumb. 450 ants is too large to visualize, but 450cm is simply the height where an old chestnut tree’s branches start. There are no 450 distinct centimeters involved in any of that, so you don’t have to keep them in your mind.
Compress down, guesstimate a piece of physical distance, continue with your day. Whether that mental model started as 15 foot or 450 centimeter isn’t really relevant, as long as you have developed a sense for the size of various things in your chosen units, and the units map nicely to other common units you might encounter. If you need any more precision, you take out your tools.
True, I converted metric to imperial with minimal rounding, as I didn’t want to give either an unfair advantage. You could round up again to 5-6.2 or down for 4.8-6.2 but my point stands. I think most people would prefer if the units they used most often were in the range of 0.2-10-ish. I don’t think that’s unreasonable.
You can memorise that a person is 10 billion nanoangstroms tall if you like, but surely you can’t be saying that it’s more convenient than using a scale that’s the same order of magnitude as the thing itself. That’s why we use the metric system after all, to give many units as close to the scale of what we’re trying to measure as possible in a standardised way.