民主原則之規範性困境，今日已於所有民主國家的政治生活中，展現為層出不窮的民主危機。尤其因為民粹威權主義於成熟民主國家的大行其道，民主危機的解決已成為當代民主迫在眉睫的問題。為求取釜底抽薪的解決之道，則必須從理論層面出發，對民主之概念進行徹底的反省。然而，法學本身顯然難以克服此一困境，而必須將道德哲學與政治哲學的理論資源與方法納入視野之內，以便從規範性證立民主的基本內涵開始，循序漸進地獲致其反映於制度層面應有的具體內容。 　　過往的民主理論證立民主之所以具有無法克服的困難，是因為其終須依賴當代多元社會下有爭議的道德信念。對此，本文以Jürgen Habermas的「論辯倫理學」為基礎，從而對民主的基本精神提出無爭議的規範性證立。透過論辯倫理學的進一步推演，Habermas亦導出「法律論辯理論」，以說明法律作為施展強制力的工具是如何被證立的。藉由結合論辯倫理學與法律論辯理論，便能將民主強制付諸於日常生活的實踐之中，據此呈現出民主作為憲法原則的應有樣貌。植基於此一的路徑，本文拓展了Habermas的理念，從而證立並闡發民主的核心精神。 　　此一依循論辯倫理學及法律論辯理論所獲致的民主原則內容，即為審議民主理論。依據前述的理論奠基，本文認為審議民主理論蘊含的內容可歸結為「論辯之基本權」以及「政治平等諸規則」兩大理念，並能透過基進民主理論的批判以深化對後者的理解，從而闡發審議民主理論的基進意涵。「基進審議民主」明確而豐富的內容不僅宣告著民主原則規範性困境之解決，也同時於實踐上提出了化解民主危機的制度建議。 / In the political life of all democracies, the normative dilemma of principle of democracy has appeared as endless crises of democracy. Accrodingly, to solve the crisis of democracy thus becomes an urgent issue for the contemporary democracy. As populist authoritarianism propagated on a upsetting scale around developed democracies, finding a resolution also grows more significant. To solve this problems once and for all, we must proceed forward from a theoretical perspective that indicate a profound reflection on the concept of democracy. Because jurisprudence becomes manifest in lack of proper paths to overcome this dilemma by itself, incorporating the theoretical resources and methods of ethics and political philosophy into the field of vision may be imperative and necessary. With the foundation that justifies fundamental connotations of democracy in a normative approch, we will obtain the specific contents that democracy reflects at the institutional level progressively. 　　Previous works on democratic theory are so difficult to justify democracy per se because their justifications depending on controversial moral beliefs in contemporary plural society drift into failure. In this regard, Jürgen Habermas advanced the “Discourse Ethics” which suggests a non-controversial normative justification of democratic essences as the most promising theory at present. Through employing Discourse Ethics, Habermas deduced “Discourse Theory of Law” to explain how to justify law as a compulsory instrument. In this manner, democracy can be forced into daily life, via combining Discourse Ethics and Discourse Theory of Law, to draw a ideal form as a a constitutional principle. Through the illustration of Habermas's doctrine, this thesis tries to broaden the ways to understand and describe the democracy. 　　“Deliberative Democracy” is the very idea derived from Discourse Ethics and Discourse Theory of Law. Based on the foundations of the above, this thesis suggests that the contents of Deliberative Democracy can be attributed to the two basic concepts including “fundamental rights of discourse” and “rules of political equality”, which, through criticisms of radical democracy, shall be further deepen the understanding of the latter to elucidate what radical meanings do Deliberative Democracy have. With specific and profuse contents, radical deliberative democracy not only invents a solution to the normative dilemma of principle of democracy, but puts forward institutional proposals to resolving crises of democracy in practice simultaneously.