At the heart of King Lear lies the relationship between father and child. Central to this filial theme is the conflict between man's law and nature's law. Natural law is synonymous with the moral authority usually associated with divine justice. Those who adhere to the tenets of natural law are those characters in the text who act instinctively for the common good — Kent, Albany, Edgar, and Cordelia.
Eventually, Gloucester and Lear learn the importance of natural law when they recognize that they have violated these basic tenets, with both finally turning to nature to find answers for why their children have betrayed them. Their counterparts, Edmund, Goneril, Regan, and Cornwall, represent the evil that functions in violation of natural law. All four conspirators are without conscience and lack recognition of higher moral authority, since they never consider divine justice as they plot their evil. Their law is man-made, and it focuses on the individual, not the good of the community. Tragedy unfolds as two carefully interwoven and parallel stories explore the abandonment of natural order and the unnatural betrayal of parent and child.
In the primary plot, Lear betrays his youngest daughter and is betrayed by his two oldest daughters. In almost identical fashion, the subplot reveals another father, Gloucester, who betrays his older legitimate son and who is betrayed by his younger illegitimate son. In both cases, the natural filial relationship between father and children is destroyed through a lack of awareness, a renunciation of basic fairness and natural order, and hasty judgment based on emotions. By the play's end, the abandonment of natural order leaves the stage littered with the dead bodies of fathers and their children.
In the opening act, Lear creates a love test to justify giving Cordelia a larger share of his kingdom. Although his kingdom should be divided equally, Lear clearly loves Cordelia more and wants to give her the largest, choice section of his wealth. In return, Lear expects excessive flattery and gushing confessions of love. But instead, Cordelia's reply is tempered, honest, and reasonable — custom dictates that she share her love between her husband and her father.
Just as soon as Cordelia fails to meet her father's expectations, Lear disinherits her. At Cordelia's loss, Goneril and Regan are quick to take advantage. They may have genuinely loved their father at one time, but they now seem tired of having been passed over in favor of their younger sister. After Lear states his obvious preference for Cordelia, the older sisters feel free to seek their revenge, turning the family's natural order on its ear. At the same time, Lear fails to see the strength and justice in natural law, and disinherits his youngest child, thus setting in motion the disaster that follows. Lear puts in place a competition between sisters that will carry them to their graves.
In a similar father-child relationship, the opening scene of King Lear positions Gloucester as a thoughtless parent. The audience's introduction to this second father has him speaking of Edmund's birth in a derogatory manner. Although Gloucester says that he loves both Edmund and Edgar equally, society does not regard the two as equal — and neither does Gloucester, whose love is limited to words and not actions of equality. According to nature's law, Edmund is as much Gloucester's son as Edgar is; but according to man's law of primogeniture, Edmund is not recognized as Gloucester's heir.
In one of the initial pieces of information offered about Edmund, Gloucester tells Kent that Edmund has been away seeking his fortune, but he has now returned. Under English law, Edmund has no fortune at home, nor any entitlement. Edmund's return in search of family fortune provides the first hint that he will seize what English laws will not give him. Clearly, Edmund's actions are a result of his father's preference — both legal and filial — for Edgar, his older and legitimate son. This favoritism leads to Edmund's plan to destroy his father in an attempt to gain legitimacy and Gloucester's estate. Again, the natural order of family is ignored.
Gloucester rejects natural law and a parent's love for his child when he is easily convinced that Edgar — the son he claims to love so much — has betrayed him. Gloucester also puts his faith in Edmund's command of persuasive language, when he rejects the love his eldest son has always shown him. With this move, the earl demonstrates that he can be swayed by eloquence, a man-made construct for easy persuasion, which causes him to reject natural law and the bond between father and child.
Edmund both ignores and embraces natural law. By betraying his father to Cornwall and Regan, Edmund's self-serving course of action abandons nature's order and instead foreshadows the neo-Darwinist argument for survival of the strongest individual. His ability to survive and win is not based on competitive strategies or healthy family relationships; instead, Edmund will take what he desires by deceiving those who trust and love him.
Edmund's greed favors natural law over man's law because natural law doesn't care that Edmund is illegitimate. He claims nature as his ally because he is a "natural" offspring, and because man's law neglects to recognize his rights of inheritance. But, nature only serves Edmund as a convenient excuse for his actions. His actions against his brother and father are more a facet of greed than any reliance on natural law.
One might argue that Gloucester's cavalier attitude toward Edmund's conception mitigates Edmund's actions. When combining this possibility with Edmund's final scene, in which he tries to save Cordelia and Lear, Edmund clearly shows himself to be of different fabric than Goneril, Regan, and Cornwall. In many ways, Gloucester is responsible for what Edmund becomes. Edmund is as much Gloucester's son as is Edgar. In embracing the man-made laws that reject Edmund's legal rights, Gloucester is denying natural laws that would make Edmund and Edgar equal.
Gloucester also acts against nature in rejecting Edgar without sufficient proof of his wrongdoing; thus Gloucester shares responsibility for the actions that follow, just as Lear's love test results in his rejection of Cordelia. Both men are easily fooled and consequently, they both reject natural law and their children. Both act without deliberation, with hasty responses that ultimately betray their descendants.
At the play's conclusion, Goneril and Regan's abandonment of natural order and their subscription to evil has finally destroyed them. The audience learns early in the final scene that Goneril has poisoned Regan and killed herself. Their deaths are a result of unnatural competition, both for power and for love. But Lear is the one who set in motion the need to establish strength through competition, when he pitted sister against sister in the love test.
For the audience, the generational conflict between parent and child is an expected part of life. We grow impatient with our parents and they with us. We attempt to control our children, and they rebel. When Goneril complains that Lear and his men are disruptive and out of control, we can empathize — recognizing that our own parent's visits can extend too long or that our children's friends can be quite noisy. Shakespeare's examination of natural order is central to our own lives, and that is one of the enduring qualities of King Lear.