The first part is an account of the Trinity Controversy, centering on the question of the identity of persons, and of the respects in which points made in the controversy, in particular the circularity objection, may have influenced Locke’s formulation of his theory. The second part argues that Locke is attempting to come to grips with the circularity problem, but that his solution is ultimately a failure. The argument of II, xxvii, 13 is analyzed in detail and the form of (...) Locke’s theory of relative identity is discussed. Fundamental difficulties are found to reside in his theories of representation and agency. (shrink)