Wow!  I found an instance where Feynman turned out to be wrong about something!

The Textbook League (no, I did not just make that name up) republished the part of Feynman’s book Surely You’re Joking, Mr. Feynman describing his participation in the State [California] Curriculum Commission’s efforts to choose new textbooks.

The commission did some phenomenally idiotic things, up to and including rating one textbook that was “printed” with entirely blank pages.  (They rated it favorably.)  Of course, you already knew that, since you have already read Feynman’s books.

As I reread it online, this excerpt in particular stood out:

They would talk about different bases of numbers — five, six, and so on — to show the possibilities. That would be interesting for a kid who could understand base ten — something to entertain his mind. But what they turned it into, in these books, was that every child had to learn another base! And then the usual horror would come: “Translate these numbers, which are written in base seven, to base five.” Translating from one base to another is an utterly useless thing. If you can do it, maybe it’s entertaining; if you can’t do it, forget it. There’s no point to it.

When this happened in 1964, there was probably no point at all.  Today, however, every software developer has had (at least once) to convert base 10 into base 16 or base 2.  Those like me found the exercise frustrating at first.  If only there’d been some sort of practice for this in the mathematics textbooks of my childhood!

(I’m mostly joking — surely! — but I do find interesting how that analysis might be completely different today.)