「宗教信仰自由」（freedom of religion）在歷史的發展中，一向是一個多向度、具多元意義的概念。在不同的時空及文化背景之下，對宗教及自由的不同理解，會產生不同的宗教信仰自由觀。因此，一個宗教信仰自由概念的鋪陳與論述，必然與神學的反省、哲學的分析、法律與政治的論證相關。基督教會的歷史歷經了311年君士坦丁的米蘭敕令（Edict of Milan）以及狄奧多修（Theodosius I）的宗教敕令（Edict of Thessalonica），始終以容忍原則（principle of tolerance）來顯示教會在旅程世界中的教義信仰自由的價值。教宗若望二十三世的《和平於世》通諭以及梵蒂岡第二次大公會議，均將信仰自由確定為基本人權，人人有按其良心選擇任一宗教之自由。這一里程碑被論者說成由容忍到人權或由客觀真理到位格權利的轉折。 梵二的《信仰自由宣言》，引發以下問題的討論：一、難道信仰的真理在宗教信仰自由中，絕對性的退居於人的自由意志及良心之後？如果答案為「是」的話，二、難道會錯誤的良心，有權利犯錯，而且這項錯誤的權利還是受到神學論述的肯認；三、若沒有宗教在真理的主張上有任何優先權利，那麼是否教宗庇護十二世的「容忍原則」在梵二之後就不復存在？四、梵二的「哥白尼倒轉」是否真是一種本質的倒轉，以致成為信理的倒轉？五、《信仰自由宣言》以前的教宗，如額我略十六世、庇護九世以及良十三世，有關宗教自由的論述是否與《宣言》相一致？本文旨在嘗試透過歷史溯源、宣言的分析、神哲學反省以及政治反省，說明以上問題。

“Freedom of religion” has always been a multi-dimensional concept with multiple meanings in the development of history. The various understandings of religion and freedom in different time, space and cultures create different views on freedom of religious belief. Therefore, the concept of “freedom of religious belief” is necessarily related to our reflection of theology, analysis of philosophy, and the discourses of law and politics. By issuing the Edict of Milan of Constantinus I Magnus (311 C.E.) and the Edict of Thessalonica of Theodosius I, the Church revealed the value of freedom of religious belief in life’s journey with the “principle of tolerance.” Both “Peace on Earth (Pacem in Terris)” issued by Pope John XXIII and The Second Vatican Council have identified the freedom of religious belief as a fundamental human right, namely, man has the freedom to choose any religious belief in accordance with his conscience. These key events in history have been regarded as a turning point from tolerance to human rights, or from the objective truth to the personal right. The “Declaration on Religious Freedom” of The Second Vatican Council has evoked the following discussions: 1) Is religious truth secondary to man’s free will and to his conscience? If so, then, 2) Is the fallible conscience which has the right to make mistakes proved by theological statements? 3) Is the “principle of tolerance” of Pius XII no longer valid after the Second Vatican Council, since no religious truths fi*om any religion possess the priority? 4) Is the “Copemican Revolution” in the Second Vatican Council such an essential revolution that it has become a revolution of truth of faith? 5) Do the statements concerning freedom of religious belief from Gregory XVI, Pius IX and Leo XIII concord with the “Declaration on Religious Freedom”? This paper attempts to respond to these questions through history, analysis of the “Declaration on Religious Freedom,” and reflections on theology, philosophy and politics.