For Brook, Lear is a series of intellectual strands which only performance can tie together. Far from being an “unactable play,” he believes its full meaning can only be comprehended existentially—on a stage. He sees it mainly as a play about sight and blindness.
Gloucester, who does not see Edmund's villainy, loses his eyes. Edgar, who does not see his brother's covetousness, loses his freedom. Lear, who does not see the corruption and rancor that see the within his family and state, loses his senses and ultimately his life. Everywhere one looks, one sees only the facades and emblems of a world and, ironically, as characters acquire sight, it enables them to see only into a void.
Fable: A blind man, resolved to die, is led up a steep mountainside by one he takes to be a naked lunatic. The steep mountainside is, in reality, a flat field; the naked lunatic, his son.