In truth, how can one reasonably "teach" what one has not already "learned".
We hire wilderness guides to take us on paths of exploration and discovery. It is not necessary even that the guide has been there personally to a specific place, a particular road -- only that they are skilled in the going, the sharing, and the improvisation in the face of the new.
The best teachers I've known are like such guides. They are full of knowledge, and empty of knowledge. I may learn many things from them, detailed, specific, and precise. At the same time, I'm learning how to explore, how to more safely and enjoyably discover the unknown.
For me, a teacher is someone who can transmit to me how best to live with the known, the unknown, and the unknowable.