Final answer:
The event in Billy Pilgrim's life that correlates with becoming 'unstuck' in time involves History, tied to his WWII experiences such as the Dresden bombing. New Historicism views history and literature as dynamically interconnected, which is reflected in Billy's narrative in 'Slaughterhouse-Five'.
Step-by-step explanation:
The event in Billy Pilgrim's life most closely connected with his claim of becoming "unstuck" in time is connected to History, which can be tied to the traumatic experiences he had during World War II, particularly the Dresden bombing, which is the catalyst for his time-shifting experiences in Kurt Vonnegut's novel Slaughterhouse-Five.
New Historicism asserts that our understanding of history should not be merely as a progression of facts and events, but rather as a dynamic interplay of various forces that includes economic, cultural, political, and social aspects. This perspective aligns with Billy Pilgrim's nonlinear experiences of time, as it suggests literature and real-life events such as wars shape one another in complex ways. The influence of history on literature is evident when analyzing works that are impacted by their historical context, similar to how Billy's experiences in WWII affect his narrative within the novel.
Literature is not only shaped by but also shapes history in turn. This concept is explored in Slaughterhouse-Five, as Vonnegut uses Billy Pilgrim's life and his becoming 'unstuck' in time to comment on the nature of war and human experience. This illustrates the New Historicist's approach whereby literature is both a product and a shaper of historical and cultural contexts.