A few weeks ago, while giving unofficial swimming lessons to an acquaintance about my age, I had an insight. It was that before you can teach something, you have to realize it’s hard.

I don’t think I noticed this before, because I thought it was obvious. Of course someone who doesn’t know how to swim isn’t going to learn perfect front crawl just by looking at yours. If I was told to watch someone else swimming a brand-new stroke that I’d never seen before, I could imitate it pretty easily, because to me it’s a trivial skill. But to someone who has nothing to refer to, it’s hard.

“You’re like the fifth person who’s tried to teach me how to swim,” my acquaintance said as I led her into the shallow end holding a foam noodle. “People just tell me to move my arms and legs, and they didn’t seem to understand why I couldn’t do it.”

There are, needless to say, a lot of different ways to move your arms and legs. Some of them resemble swimming. A subset of those actually work to keep someone’s head at the surface, and an even smaller subset of those are effective enough that they have names, like front crawl. To me, this is obvious, because I’ve watched hundreds of children in my classes flail and struggle in their front crawl, or lift their head to breathe, or turn their toes inwards in whip kick, and make the same mistakes persistently even when I corrected them, both verbally and by literally grabbing their arms/legs and moving them. I know it’s hard.

I went through this flailing/struggling phase too and have no memory of it whatsoever, having been three at the time.  This is probably true of most good swimmers; the procedural memory is so embedded that it makes sense to say “move your arms and legs” because that's all you think about consciously; you forget how many other things you’re doing just to stay afloat. (Poor swimmers might have a different perspective, but they aren’t likely to use that perspective to try to teach other people how to swim.)