It can be fairly said that after the classic initial discussion of the problem of personal identity by John Locke, and the responses to that discussion by Butler, Reid and Hume (Leibniz’s insightful response going largely unremarked) the shape of the controversy was fixed for the next 200 years. Of course, later philosophers had new things to say, and new ways to say old things, but the framework of their discussion of the problem remained the one determined by the writings of Locke, Butler, Reid and Hume. There was the issue between materialists and their opponents; the question whether the self was a simple substance, or something whose identity consisted in a set of relations between successive substances; the controversy between proponents and opponents of the Humean ‘bundle theory’ of the self. The framework for the discussion of the problem was fixed and remained so until as late as 1956. In that year, however, Bernard Williams published his seminal paper, ‘Personal identity and individuation’ (1956-7), in which he put forward his famous Reduplication Argument. This argument transformed subsequent discussion of the problem and led philosophers to the formulation of positions which were wholly new. Most notably, as a result of his reflection on Williams’s argument (mediated by Wiggins’s discussion of fission, Wiggins 1967) Parfit came to the statement of his famous and wholly original thesis ‘identity is not what matters in survival’. This has been one of the main foci of interest in the debate over personal identity since its formulation. In addition, as we saw in Chapter 1, the Reduplication Argument has seemed to many of the defenders of the Simple View to be a new and powerful argument in favour of their position (an emphasis to be found particularly in Richard Swinburne’s writings), and in consequence in recent years there has been a considerable revival of interest in the Simple View.