Here, Edmund speaks as a hero, the so-called "good guy," who stands up to evil at the risk of his own life. In Shakespeare's time, the testimony of a legitimate son would weigh more significantly than that of an illegitimate son; but in this instance, Edgar is not available to present his position. Gloucester easily accepts the illegitimate son's words, while rejecting a lifetime of evidence of Edgar's worthiness, illustrating how out of step the world has become with nature. According to natural order, years of devotion and love should lead to trust, but with the events of Act I, fathers no longer trust their children's love. Instead, fathers are easily fooled into rejecting the children who love them most. Lear has rejected the daughter who genuinely loves him, and now, Gloucester has rejected the son who genuinely loves him. These events further support the idea that Lear's earlier actions have rejected the natural order of the world.
Regan and Cornwall's visit gives Edmund another opportunity to advance his plot. In this scene, Regan and Cornwall appear to be conscientious and reasonable people. Regan seems genuinely upset to learn of Edgar's betrayal. That Regan has come seeking Gloucester's advice also adds to her credibility because it creates the impression that she values the older man's guidance.
Cornwall's acceptance of Edmund's story and his welcoming of Edmund into his clique foreshadow the evil that will emerge from Cornwall and provide a hint to the audience that Cornwall is not the nice guy he appears to be. As for Edmund, Cornwall's invitation offers him the chance to ally himself with Cornwall. Since Albany attempted to intercede on the king's behalf in Act I, the audience expects Cornwall to emerge as a villain, and his alliance with Edmund emphasizes that both men are evil figures. Gloucester, playing the part of a gullible old man, has no real reason to distrust either Edmund or Cornwall — neither has proven untrustworthy in the past.
