羅爾斯於一九九三年發表《政治自由主義》，試圖為多元社會的整合提供一套哲學基礎。羅爾斯認為價值的差異與分歧是當代社會的重要特徵，多元的宗教觀、哲學觀、道德觀、人生觀是一個既存的事實，然而合理的公民能夠形成「交疊共識」，支持一套政治性正義觀，作為規範社會基本結構的基礎。尤其在面對憲政核心爭議與基本正義問題時，合理的公民能夠擱置具爭議性的整全性學說，遵循公共理性的理念，根據同一套政治性正義觀所提供的政治價值與正義原則來解決爭議、凝聚共識、證成決策。不過，羅爾斯的公共理性論受到許多批評，其至少面臨「公共理性無法證成政治共識」、「公共理性不公平地排除整全性學說」、「公共理性是多種而非一種」、「公共理性將淪為膚淺的大眾理性」四種挑戰，此四種挑戰分別是對於公共理性之「完備性」、「公平性」、「單一性」、「公共性」的質疑。針對這些挑戰，羅爾斯對其理論進行了三項主要修正：第一，以「寬觀點公共理性」與「包含式公共理性」補充「排除式公共理性」。第二，公共理性的內容是由一整套「自由主義政治性正義觀之族系」所給定，「正義即公平」也只是諸多合理的政治性正義觀之一。第三，羅爾斯承認公共理性的侷限，然而在必要時，得以「基於公共理性的投票」做出決策。根據這些修正，筆者認為羅爾斯的公共理性論能夠回應「完備性」、「公平性」、「單一性」三方面的挑戰，但是仍無法完全解決「完備性」的問題。因此在本文中，筆者試圖以「寬觀點公共理性」與「廣泛的反思均衡」證成「羅爾斯式的審議理論」，以突破公共理性的限制。尤其是筆者認為，「羅爾斯式審議理論」具有「公共證成的審議模式」、「尊重民主文化」、「兼顧程序正義與實質正義」、「滿足『真誠要求』」、「強化公民意識」、「重視公共理由」等特質，體現了一種自由主義式的審議式民主理論。因此，當我們思索「多元社會的政治共識如何可能？」時，「羅爾斯式審議理論」是一項較合理的方案。 / This dissertation intends to explore John Rawls’s idea of public reason. Public reason is the core conception of Rawls’s political liberalism. Its subject is the public good concerning questions of fundamental political justice. Rawls argues that, though value diversity is the fact of a modern democratic society, reasonable citizens will follow a political conception of justice endorsed by the overlapping consensus between different kinds of comprehensive doctrines in order to resolve the deep conflicts. Especially, when the problems about constitutional essentials and basic justice occur, reasonable citizens will abide by the idea of public reason to deal with the problems. The idea of public reason is helpful for us to justify political consensus in a pluralistic society. However, some philosophers challenge the idea of public reason. They criticize that the idea of public reason cannot deal with the hard issues such as abortion, euthanasia, and affirmative action. Faced with these criticisms, Rawls revises his theory in three aspects. First, he revises the exclusive view of public reason by the inclusive view of public reason and the wide view of public reason. Secondly, he argues that the content of public reason is given by a family of reasonable political conceptions of justice. Thirdly, he asserts that we can make a political decision by voting in accordance with the idea of public reason if it is necessary. But, these revisions seems cannot completely overcome the shortcoming of the theory of public reason. Therefore, I want to justify Rawlsian deliberative theory based on the wide view of public reason and the wide reflective equilibrium to overcome the shortcoming of the idea of public reason. Owing to Rawlsian deliberative theory can reconcile liberalism and deliberative democracy, strengthen our civic friendship, and urge us to value public reasons more, I think it is a more plausible theory to justify political consensus in a modern pluralistic society.