Locke's most important work from the perspective of political scientists and historians, the Second Treatise, was in significant part an exercise in moral philosophy. He wrote much on morality and the possibility of its proof and developed a theory of personal identity to anchor moral responsibility that is still influential today. It is extremely tempting therefore to attempt to associate Locke with a consistent extended and fully articulated moral vision. As we will see, however, Locke never wrote a treatise on anything like the full content of ethics despite the many requests of his friends and his own recognition of the importance of this task. His ethical views changed significantly during his life. His moral thought was often remarkably fragmentary and rudimentary. Several problems that he encountered in the way of establishing a demonstrable ethics were considerable, and he found no way of solving these problems. Locke's thought could perhaps be made more consistent by identification of elements of his works and jottings with the more extended thought about these issues of a number of authors whose work he recommended or translated, including especially Nicole, Cicero and Pufendorf, but he never adopted their thought wholesale, and his recommendations of each were always significantly limited. These and other authors, particularly the Latitudinarians, provided him with laudable accounts of significant elements of a broad morality of which he approved, but he held significant reservations about parts of their arguments and apparently did not see a way to improve as much as he desired upon these arguments.