本文之目的，是試圖從哲學的進路，分析與重建流行於戰國楚國與西漢武帝時代的「太一」信仰與崇拜。從語意上來說，「太一」是指最高之實有（utimate reality）。在人類歷史中，信仰最高之實有或超感官之實在性的存在，是大多數宗教中最顯著的共同面相。在商代，人們敬拜不同的神靈，其中又以「帝」為最高。到了周代，敬「天」與畏「天命」，成為當時政治與宗教的特色。進入東周的春秋時期，老子提出「道」的形上概念，作為世界的第一因，取代了「帝」與「天」。「太一」則是出現於戰國與西漢的神話與宗教崇拜。我們的哲學傳統之基本關懷是以人文為本，而不在於宗教上的神性與哲學的形上理論。事實上，傳統的中國思想家們只關懷宗教與哲學對人生的影響，而罕有對宗教與哲學的本質表現興趣。例如，我們的祖先們雖然曾把「天」視作物理世界與道德世界之終極原理，但其所關懷的，基本上是如何與「道」合一，這就是在傳統上所謂「天人合一」說。在漢武帝時期，「太一」可視為「天」、「帝」或「道」在宗教崇拜上的表現。但是，「太一」崇拜卻一直缺乏形上學的基礎。因此，針對「太一」的宗教現象而確立其哲學根基，這在學理上是必要的。 在討論「太一」作為最高的神明或最高實有之時，吾人無法避免要對道教的「三清」信仰作分析。因此，本文分成下列六個環節作論述。其一是，吾人試圖從哲學的層面，指出「太一」概念具有宗教與哲學的本體意義，古代猶太教與希臘哲學便是從宗教與哲學的進路，分別展示「最終實有」的不同面相。其二是，從天象層面，說明「太一」之宗教意義，特別是戰國時期，《楚辭．九歌》中有關「東皇太一」的宗教意義。其三是，闡述漢武帝建「太一祠」與祭祀「太一」的歷史事實及其宗教意義，以及「太一」崇拜在中國歷史上的興衰。其四是，分析與闡述「三清」信仰之源流，以及「三清」之本體論意義。其五是，從本體論的實體性方面，比較「三清」與「太一」之異同，進而指出「太一」的實體性意義其實可消融於「三清」的本體屬性之中。最後，本文試圖藉著新柏拉圖主義的哲學家普洛丁奴斯的「太一」理論，以及布魯諾（G. Bruno）的「世界魂」思想，為中國歷史上的「太一」崇拜建立其哲學的理論根基。

This paper is an attempt to present (from a philosophical perspective) the worship of Taiyi which means semantically the supreme Being. The belief in the supreme Being or supersensible reality is a notable feature of most religions in human history. In the Shang Dynasty about 2000B.C., our ancestors worshipped a lot of different gods called huei-shen, a word for ghost and spirit. They believed at the same time in a master God called “di” or Shangdi, the Lord on High, who gave the Mandate to the authority of a just ruler and would be reassigned if the holder misbehaved. By the time of the Zhou Dynasty, “tien”, who was in charge of all the gods and spirits in pantheon, was worshipped. During the Eastern Zhou Period, Laozu proposed a metaphysical conception of Dao as the primordial principle of the world. By the time of Han Dynasty, the Supreme Ultimate was claimed to be Taiyi which means literally the Ultimate Origin and Ground of Being for all existence. The approach of our philosophical tradition has been humanistic, rather than centered around religious divinity and metaphysics. In fact, our ancestors had little interest in discussing the nature of religion or philosophy apart from understanding the impact they could have on people. For instance, the conception of tian which was considered as the ultimate principle gorverning the physical world and huaman morality, concerned basically with the correct function of the world. The primary concern of our ancestors was how to live in harmony with the world and they tried to realign mankind with the dao which could be religiously interpreted as Taiyi. It lacked, however, a metaphysics. Under this circumstances, the conception of Taiyi should be theoretically reinforced, and this is the basic task of this paper. In any discussion of Taiyi as the Godhead, one cannot escape to expound the belief of Sanqing daozu or the Trinity of supreme Dao. Hence, this paper is divided into the following six main parts. Firstly, from a philosophical viewpoint, we point out the concept of utimate reality in both philosophy and religions. Secondly, from an astronomical and religious perspectives, we show the heavenly body Taiyi and its religious implication, especially the signification of the so called Donghuang Taiyi (God of the Eastern Sky) of the poem Jiuge in Qu Yuan's Chuci (Lyrics of Chu) at the time of Warring States. Thirdly, we explore the historical fact that Taiyi was officially worshipped through sacrificial rituals by Han Wudi, the fifth emperor of the Western Han Dynasty and expound the ups and downs of the worship of Taiyi in the Chinese history after Han Dynasty. Fourthly, the Origin and the ontological significance of the Being of Sanqing are explored and analyzed. Fifthly, the relations between Sanqing and Taiyi are compared and contrasted, and it is pointed out that the substantial attributes of Taiyi are dissolved into the conception of Sanqing. Finally, the philosophical foundations of Taiyi and set up means of Plotinus' theory of the One together with Giordano Bruno's theory of the world soul.