"you have to know what you want in order to imagine it."
correct. For many years the Soviet Olympic athletes had a major mental advantage over Western athletes. They employed psychologists on staff to encourage their athletes to envision winning, a very powerful intuitive force, ie; to envision successfuly lifting a world record amount of weight, swimming records, etc.
It makes real life of actually doing it, easier as they already envisioned it and felt confident they could do it.
As you already know I'm highly interested about the brain and how it works. If you can imagine something and put that into execution in your chess game, you don't really need words to describe it if you're making progress. But one thing I realized is, you have to know what you want in order to imagine it.