本論文首先對共識概念的義及其觀念史的形成過程，做一簡述。經由關於言談倫理學和康德存心倫理學的對比的重檢，以釐清言談倫理學的共識理論的提出的必須性。本論文重檢了考夫曼與賀弗爾的批判和言談倫學關於規範證立問題的闡釋，使我們對當代的共識理論危機及內在於言談倫理學的共識危機的解決之道，得一較恰當之理解與回應，簡言之，賀弗爾和考夫曼的前述摝判忽略了共識和生活世界是互補概念，忽略了生活世界在共識理論中的先驗功能，本論文指出規範的「決定根據」與共識作為規範形成時的「必然對象」的區分，後者是反思性和規導性的原理。因此，共識是開放性和批判性的共識，並不和多元論哲學不相容。

Juergen Habarmas’s theory of communicative action holds that rational speakers presoppose that the achievement of consensus is the ultimate goal of communication. There are still two question: (l) Is the demand for Universalierung of consensus against the pluralism, that is the character of the contemporary society? (Hoeffe, Kaufmann). (2) Is. there a logical circle in the presupposition of the understanding of morality and the consensus and discussethies? (Hoeffe). This article try to explain: (l) The Lifeworld (Lebenswelt) is the complementary concept (Komplementaerbegriff) of consensus and has the tran­scendental function (Habermas, Apel). The Lifeworld is the transcendental horizon of the operation of communicative action and the consensus. Therefor the Universalierung of maxim of the discussethics has no sickness of formalism and there is no logical circle in the presupposition of the understanding of morality and the consensus and discussethics. (2) The theory of consensus derive their regulative principle through the postulate of the realization of the ideal communication community. By this principle of “regulative” the consensus will be a critical and open consensus in the methodological and in the ethical-normative sense of a non-subjectively arbitrary grounding of value judgment (Habermas, Apel, Kuhlmann).