Naturalization of the Soul charts the development of the concepts of soul and self in Western thought, from Plato to the present. It fills an important gap in intellectual history by being the first book to emphasize the enormous intellectual transformation in the eighteenth century, when the religious 'soul' was replaced first by a philosophical 'self' and then by a scientific 'mind'. The authors show that many supposedly contemporary theories of the self were actually discussed in the eighteenth century, and recognize the status of William Hazlitt as one of the most important Personal Identity theorists of the British Enlightenment, for his direct relevance to contemporary thinking.