|People need to be taught to do.|
So if you know how to do that's
all that matters.
Plus, this saying doesn’t even really make sense. An English teacher teaches because they can’t DO English? What is there to do with English besides teach it?! Read it? Well they can certainly read it so that’s wrong. And of course a math teacher can do math. If they couldn’t what would that class be like? So if they can’t do math, they can teach it? That literally makes no sense. If they can’t do it they can’t teach it. They’d just be letting students read from the textbook and try to figure it out themselves. That’s not teaching. “Those who can’t do, can’t teach” makes more sense. I don’t think anyone would argue with that saying.