Contrast with a gallon, which is too much liquid for most people to ever drink in one sitting. I feel I have way less handle on a gallon than on a liter.

Also, this guy's arguments come off as really shallow. To quote from what you're citing:

> A meter does not match anything; a foot does. I can imagine the meaning of “thirty feet” with minimal effort. A mile, from the Latin milia passum, is a thousand paces. Likewise a stone (14 pounds) corresponds to . . . well, a stone. An inch (or pouce) corresponds to a thumb. A furlong is the distance one can sprint before running out of breath. A pound, from libra, is what you can imagine holding in your hands.

These are lame ass examples.

A stone is "a stone"? Goddamn, there's stones of all sizes. You can rationalize any unit of mass that way. A furlong is how long you can sprint before running out of breath?? That surely varies a lot by athletic ability (and many people don't run at all, and certainly couldn't make a whole furlong at a fast pace). A pound is what you can "hold in your hands"? Huh? Surely that depends on the density of the material in question and the size of your hands. None of these are helping me out at all.

You can make better arguments by flipping the tables. 0 degrees is where the weather turns from rain to snow. 1 Liter of water weighs 1 Kilogram (compared to a gallon of water weighing 8.336 pounds). 1 Kilometer is simply 1,000 meters. I could continue but I think I've made my point.

The author hasn't demonstrated that legacy metric systems are innately superior. All he's demonstrated is that it can be hard for people to switch, which is true of many people. He hasn't a lick of evidence pointing to people in SI-using countries being less able to visualize what a kilogram or liter or kilometer are. And he won't be able to, because all units are arbitrary, and SI's convenient allowance for powers of ten always allows you to pick a right-sized unit to work with that doesn't yield a number that's either too big or too far off into the decimals.