To invent out of knowledge means to produce inventions that...

To invent out of knowledge means to produce inventions that are true. Every man should have a built-in automatic crap detector operating inside him. It also should have a manual drill and a crank handle in case the machine breaks down. If you're going to write, you have to find out what's bad for you. Part of that you learn fast, and then you learn what's good for you.