Moral practice is a selective social interaction based on moral beliefs and norms held by moral subjects. Self-consistent moral belief and its cognitive system are prerequisites for moral subjects to engage in their moral activities freely and firmly. Because of the complexity of the moral practice situation, the conflict between the good feelings and the moral principles inevitably occurs, which leads to the dilemma of moral choice when moral subjects engage in moral activities and fulfill their moral obligations, resulting in the confusion of moral cognition. Eliminating the confusion and pain of moral subject requires ethics to enter into the life world in the way of philosophical consultation, so as to relieve the confusion and suffering of moral subject, and it is also necessary for ethics to clarify the paradox of reason in moral practice, so as to provide legitimacy explanation and justification direction for the practice of moral subjects at the level of moral beliefs or faiths.