This work begins with a discussion of problems of method and then surveys a number of areas of psychological researchto reach an initial idea of the psychological resources and liabilities which people typically have. There follows an organized outline of the ways in which such resources or liabilities may come to expression on each of the four levels of the subject's operations, as these are analysed Bernard Lonergan: experience, understanding, judgement, and decision. Then an analysis of the tension between human desire and human limitation provides a broader context within which the significance of temptation and conversion are examined. A clarification of the significance of specifically religious and Christian in moral theology is attempted. Finally, some implications on a more pratical level are explored.