How does the short form of Shakespeare's sonnets and the long form of King Lear allow Shakespeare different ways of thinking about old age?
There is a basic difference between the verse form and the dramatic form that goes back to Aristotle: Verse has one narrator, the “speaker,” while drama has no narrator; the story is told in the voices and actions of all the characters. For Shakespeare, this means that in King Lear we can experience age from the outside, by seeing its effects and watching its progress from “an imitation of an action.” In a sonnet, we get the personal view of a character, expressing his feelings in the condition of aging or growing (“When I do count the clock that tells the time”) or seeing his lover aging (from the same sonnet: “That thou among the wastes of time must go”). So the immediacy of the sonnet, more emotionally effective, can be contrasted to the dramatic unfolding of age, as seen by the other characters. A famous line from Richard III is emblematic of Shakespeare’s ability to forge the two into one expession by using a soliloquy – Richard, in prison, says “I wasted time, and now does Time waste me.”