The theory of the objective correlative as it relates to literature was largely developed through the writings of the poet and literary critic T.S. Eliot, who is associated with the literary group called the New Critics. Helping define the objective correlative, Eliot's essay "Hamlet and His Problems", republished in his book "The Sacred Wood: Essays on Poetry and Criticism" discusses his view of Shakespeare's incomplete development of Hamlet's emotions in the play "Hamlet". Eliot uses Lady Macbeth's state of mind as an example of the successful objective correlative: "The artistic 'inevitability' lies in this complete adequacy of the external to the emotion….", as a contrast to Hamlet. According to Eliot, the feelings of Hamlet are not sufficiently supported by the story and the other characters surrounding him. The objective correlative's purpose is to express the character's emotions by "showing" rather than "describing" feelings as discussed earlier by Plato and referred to by Peter Barry in his book "Beginning Theory: An Introduction to Literary and Cultural Theory" as "...perhaps little more than the ancient distinction (first made by Plato) between mimesis and diegesis…." (28). According to Formalist critics, this action of creating an emotion through external factors and evidence linked together and thus forming an objective correlative should produce an author's detachment from the depicted character and unite the emotion of the literary work.