In a soliloquy, Edgar explains that he escaped the "hunt" (2.3.3) sent after him by hiding in the hollow of a tree. Now that nowhere is safe for him he intends to disguise himself in the "basest and most poorest shape/ that ever penury in contempt of man/ brought near to beast" (7-9)—that is, as a "Bedlam beggar," or madman escaped from an asylum—and give up his own identity: "Edgar I nothing am" (21).
Transforming his outward appearance into that of a nearly animal, naked madman, Edgar seeks to escape the unjust (or blind and misled) workings of the law. Like Lear (whom the Fool calls "nothing" in 1.4), Edgar annihilates his own identity. However, Edgar does so knowingly and purposefully, and in doing so is able to pretend madness without actually going mad, while Lear did so in error, and is therefore slipping into actual madness.