King Lear: Theme Analysis

King Lear is a Shakespearean tragedy that illustrates what happens when children are consumed by greed and lose their love for their parents.  The play focuses on deception, greed, cruelty, and misjudgment.  Often the disguise or deception is not physical but emotional.  The few characters that must physically disguise themselves in the play are the few characters that are not motivated by darker emotions.  Kent and Edgar disguise themselves: one to help the king, the other to escape punishment. In the end, Shakespeare shows them to have pure and decent motives. The dukes and two eldest daughters however, who at no time in the play hide their face nor their actions, do hide their true nature. The daughters trick their father into believing that they love him above all else.  Edmund, too, tricks his father into thinking he is a loving devoted son, and this is to hide their true greediness. 
Declarations of love in the play are many, but mean only that the person giving the love wants something in return.  This is perhaps Shakespeare's way of saying that "Actions speak louder than words." Whereas Cordelia refuses to give flowery words of her love for her father, she proves herself to him by showing him compassion and forgiveness.  These declarations lead to the misjudgment of character that runs rampant through the play.  Gloucester and Lear both misjudge their children, because of whom one goes blind and the other loses his sanity.  It is only after this happens that they both can finally see the true character of their offspring. 
Lastly, the play is about passion that wipes away all reason.  Edmund has a passion for the title of Earl of Gloucester and Regan and Goneril each have a passion for power. Lear's passions cause him to do unwise things such as leaving during a raging storm, and cutting off his most devoted child.  Cordelia, even though she is portrayed as a pure character has a passionate nature as well.  Her passion is for truth.  Passion, greed, and deception all lead to one climactic ending with the many of the characters dying at once from the end results of their vices.