As a result of his ignorance at the changing state he is incapacitated. If we look at the opening scene of the play we are already in a world ideologically very different from our own.
"Meantime we shall express our darker purpose.
Give me the map there. Know that we have divided.
In three our kingdom." - I, i, 36-38 p. 945. .
(All page references to the Oxford edition, 1998.).
For Shakespeare's audience the reference to their current political situation is current enough, for a later audience an idea of perversity and inevitable doom is set in through historical knowledge. The kingdom divided is open to attack from the individual seeking power. We see in the contrast between Cordelia and her sisters the conflict between the political ruthlessness of ambition and natural humanity. It is Lear's lack of insight that leads him to mistake Regan and Goneril's political allegiance for familial love, and Cordelia's refusal to speak as insolence.
"Unhappy that I am, I cannot heave.
My heart into my mouth. I love your majesty .
According to my bond, no more nor less." - I, i, 91-93, p. 945.
Cordelia represents the natural distinction between political and familial life, and it is an important one for the play. She expresses what is both "honourable and natural" 1. She cannot "mend her speech a little" by bringing her love for Lear as her father into the political forum. Lear however fails to see, as Cordelia does, that a new ruthless order is taking over the old one, it is one in which the "forms of kingship and hierarchy are [no longer] the basis and reality of the world"2. Lear, in not being able to comprehend the changing world and his daughters" usurpation of his authority, loses his mind. He doesn't understand his situation and so cannot affect it.
Gloucester, like Lear, is part of the old way and is also blind to the aspirations of individuals. He must be literally blinded before he comes to believe and trust in the new natural humanity of Edgar and Cordelia.
