What is the dramatic significance of the sub-plot in King Lear?
In King Lear, the Earl of Gloucester’s storyline resembles Lear’s. In both cases, a powerful older man thinks he knows his children better than he does. They turn against their loyal children and are duped by their duplicitous children. Lear disowns the honest Cordelia and gives his kingdom to the flattering Goneril and Regan. Gloucester’s illegitimate son Edmund tricks him into believing his legitimate son Edgar is plotting against him. Goneril and Regan strip Lear of power, shut him out in the cold, and defend their actions in a war that leads to Lear’s death. Due to Edmund’s scheming, Gloucester loses his eyes, and his heart eventually gives out.
There is redemption in both of their stories, however. Lear reunites with Cordelia before they die, realizing that he is “a very foolish fond old man.” Edgar also meets Gloucester, cures him of his desire to kill himself, and eventually reveals himself to him. This revelation gives Gloucester joy but also kills him: his heart, “'Twixt two extremes of passion, joy and grief, / Burst smilingly.” One of the lessons learned in both plots is that a man, especially a powerful one, can be too comfortable in his ignorance. Gloucester is less ornery than Lear, but he is careless about Edmund’s mental state. Both fathers are humbled to discover how deceiving appearances can be, even in their own families.