Understanding the major themes in King Lear are essential to understanding the play. We'll take a look at the theme of blindness in King Lear along with a look at appearance vs. reality.
The theme of blindness in King Lear is perhaps the most discussed. I shall add to the discussion.
Cornwall and Regan poke out Gloucester's eye in retaliation for his aiding of Lear. This physical blindness represents the symbolic blindness of Gloucester and Lear: (1) They are both blind to the intentions of their children, wrongfully banishing the loyal one and rewarding the devious ones; (2) They are blind to their responsibilities. Gloucester's adultery leads to the illegitimate Edmund who causes strife in his kingdom. Lear's abdication of the throne and handing over of power to self serving individuals leads to his downfall; (3) It is also apparent that Lear was blind to the needs of his people during his reign as evidenced by his remorse over not taking care of the less fortunate.
Along with blindness, madness plays an important role. The mad babblings of the fool carry wisdom much in the same way Lear finds wisdom as he goes mad. It is probable that Lear's madness causes the tragedy as much as the tragedy causes his madness. Lear's behavior in the play's opening scene shows signs of mental illness, an illness that perhaps his most loyal daughter and most loyal servant recognize. This could be why the two remain loyal to the king, notwithstanding his ill treatment of them.
Appearance vs. Reality
Closely related to the theme of blindness in King Lear is the understanding of appearance vs. reality. It, therefore, occupies the next spot in our discussion.
Nothing is as it seems in the play. The king isn't really the king anymore. The good daughters are the bad daughters and the disowned daughter is the only true daughter. Edgar is the loyal son, but is made to look like a traitor while Edmund, the traitorous son, appears to be the savior of the family. The fool is wise and the wise are fools.
Disorder reigns as Goneril becomes the authority figure in her relationship with Albany, even taking over rule of the military. The sisters are anything but sisterly, attempting to win the heart of the ruthless Edmund, who has no heart. Poor Tom (Edgar) is a the son of a nobleman and Caius the beggar is actually the loyal Kent. Those who are loyal have every reason to be disloyal and those who are disloyal have every reason to be loyal.
A look at King Lear major themes must include a discussion of King Lear's responsibilities and how is abdication brought forth negative consequences.
At the heart of all the problems present in the play is the lack of responsibility demonstrated by Lear and Gloucester. Lear, according to England's divine right of kings, has a responsibility to his subjects, which he carelessly turns over to his two wicked daughters. In addition, he has responsibilities toward Cordelia, his youngest, to take care of her. Cordelia as well has a responsibility to take care of her father who is not in his right mind, something of which she is capable by merely exaggerating her love for him at the play's opening.
Gloucester has a responsibility to his wife, which he does not live up to, having committed adultery. He also has a responsibility to his sons, one of which he banishes. It's possible that his trust of Edmund stems from the guilt of bringing a bastard son into the world and the inherent shame Edmund has to bear.