Simon Oxenham quotes physicist Richard Feynman:

“I finally figured out a way to test whether you have taught an idea or you have only taught a definition. Test it this way: You say, ‘Without using the new word which you have just learned, try to rephrase what you have just learned in your own language. Without using the word “energy,” tell me what you know now about the dog’s motion.’ You cannot. So you learned nothing about science. That may be all right. You may not want to learn something about science right away. You have to learn definitions. But for the very first lesson, is that not possibly destructive?

“I think for lesson number one, to learn a mystic formula for answering questions is very bad. The book has some others: ‘gravity makes it fall;’ ‘the soles of your shoes wear out because of friction.’ Shoe leather wears out because it rubs against the sidewalk and the little notches and bumps on the sidewalk grab pieces and pull them off. To simply say it is because of friction, is sad, because it’s not science.”

Oxenham applies the above to pseudoscience:

If someone cannot explain something in plain English, then we should question whether they really do themselves understand what they profess.” —bigthink.com