Ⅴ．Conclusion: Two Kinds of Failures, or An Endless Road?

As a conclusion, the second part of this paper reconstructs Mackie's anti-realism argument and introduces the suspending principle of relativism(including Rawls’ liberalism and Berlin's pluralism) against moral disagreements.

In the third part, this paper points out three main problems of relativism. First, the moral system needs the existence of a common horizon to establish itself, so the moral value is not proved internally. Secondly,moral relativism does not conform to the intuition of cognitive companions in epistemology, and will lead people to be forced to accept the inherent legitimacy of some anti-human belief systems (such as fascism). Finally,moral relativism depends on a narrow one-way view.

In the fourth part, this paper revises Brink's argumentation obligation to demonstrate moral realism. If moral realism wants to successfully face the problem of moral disagreements, it should demonstrate that “people can form principled agreements” and give a feasible methodology to surmount the existing disagreements. This paper also points out that this requires strong argumentation obligation.

In the challenge of moral disagreements, on the one hand, it is difficult for people to accept the consequences and internal contradictions of relativism, and on the other hand, it is difficult to really think that moral realism can successfully solve the genuine moral disagreements that have lasted for thousands of years. From the opposition between Platonism and anti-Platonism, the opposition between virtue ethics and deontology to the opposition between Kantism and utilitarianism, the history of philosophy seems to show that it is difficult for people to provide real solutions through realism. The broken everyday world even contains the terrible reality that“even apparent disagreements are difficult to solve”.

Although the reality is so fragmented, and it needs to fulfill a strong argumentation obligation, the efforts of moral realism to find agreements are reasonable. Through moral discourse and rational reflection, perhaps people can constantly revise their views in the future, and go beyond the limitations of culture, history, and society to approach the picture of moral agreement.