Melvyn Bragg and his guests discuss the philosophy of solitude. The state of being alone can arise for many different reasons: imprisonment, exile or personal choice. It can be prompted by religious belief, personal necessity or a philosophical need for solitary contemplation. Many thinkers have dealt with the subject, from Plato and Aristotle to Hannah Arendt. It's a philosophical tradition that takes in medieval religious mystics, the work of Montaigne and Adam Smith, and the great American poets of solitude Thoreau and Emerson. With: Melissa Lane Professor of Politics at Princeton University Simon Blackburn Professor of Philosophy at the New College of the Humanities and Fellow of Trinity College, Cambridge John Haldane Professor of Philosophy at the University of St Andrews Producer: Thomas Morris.