Catholic and Protestant theologians believe that the resemblance between Christian and non-Christian ethics is due not only to desecration, but also to the fact that we live in the same historical order. Gustavo Gutierrez insists that there are no two histories, one profane and one sacred, juxtaposed and intimately connected, but a single history of human destiny, irrevocably assumed by Christ, the Lord of history. The naive optimism of a moral theology that does not consider human limits, and that considers human actions as if the eschatology had already been achieved, has led to an improper methodology, based exclusively on natural reason. Bernard Häring insisted, however, on the need for moral theology to be based on Scripture and grace, and not just on reason and human nature. Charles E. Curran expressed his right to disagree with the non-infallible teaching of the authority of the Catholic Church, emphasizing that Catholics could in theory and practice disapprove of papal teaching and remain faithful to the Catholic Church.