Isaiah Berlin's biographer, noted writer and broadcaster Michael Ignatieff, speculates about the relationship between philosophy and aging, and asks what philosophy had to do with Berlin's equanimity in old age. All of Berlin's thinking, Ignatieff writes, associated serenity with belonging, and belonging with self-knowledge: "If he was serene in old age it was because he knew who he was and where he belonged." Robert Alter, Professor of Hebrew and Comparative Literature, and Michael André Bernstein, Professor of English and Comparative Literature, respond to Ignatieff, assessing the role of philosophical reflection at any stage in a life trajectory.