The meaning of the word "Cave"
I was surprised to see the author confused about the meaning of the word "cave" [Well, I guess I shouldn't be, given then modern state of education]. The cave that Jack White white is talking about is the Allegory of the Cave. This is reinforced by the use of phase 2d.
The Allegory is written as a dialogue between Plato's brother Glaucon and Plato's mentor Socrates.
Plato has Socrates describe a group of people who have lived chained to the wall of a cave all of their lives, facing a blank wall. The people watch shadows projected on the wall by things passing in front of a fire behind them, and begin to ascribe forms to these shadows. According to Plato's Socrates, the shadows are as close as the prisoners get to viewing reality. He then explains how the philosopher is like a prisoner who is freed from the cave and comes to understand that the shadows on the wall do not make up reality at all, as he can perceive the true form of reality rather than the mere shadows seen by the prisoners.