Luther’s pessimism involved the denial of free will, which goes against all human experience, as well as all of Christian ethics. Luther supported his position by understanding original sin as the total corruption of human nature, such that we are no longer able to perform morally good acts or resist temptation. The Catholic understanding of original sin is that, as a result of the Fall, Adam lost for us sanctifying grace, as well as the four preternatural gifts: immortality, immunity from suffering, infused knowledge, and the gift of integrity (the submission of our sense appetites to our reason). However, human nature is not completely corrupted by the Fall, nor is free will lost.