本論文旨在探討徐谼《谿山琴況》中「絃外之音」的意涵及其與道家思想的關聯，先從《谿山琴況》來看，徐谼對古琴曲之「絃外之音」的體認與「氣」、「意」的觀念有密切的關聯，再追本溯源，則可見古琴音樂美學中「絃外之音」的意境實是源自道家藝術精神的體現，尤其是老子的「有無相生」與莊子的「心齋」說——「聽之以耳」、「聽之以心」、「聽之以氣」。道家的理念落實在古琴音樂上，先由耳與心、心與氣之平衡、和諧，使生命從世俗中解脫與昇華，在如此的心境下撫琴，才能產生「絃外之音」，體現人與宇宙大自然的和諧統一，而形成古琴音樂獨具一格的美學價值。最後，本論文以吳兆基所彈之〈瀟湘水雲〉一曲中少許樂句為例，以說明古琴音樂體現道家生命哲學所展現「絃外之音」的深層意涵。

This paper aims to investigate the significance of ＂overtone＂ in His-Shan's Epithets on Qin Music written by Hsu Hong. The concept ＂overtone＂ relates to Taoist philosophy: from the viewpoint of His-Shan's Epithets on Qin Music, Hsu Hong's experience concerning the ＂overtones＂ of guqin music is intimately linked to the human spirit(氣) and will(意). A reading of ancient literature shows that the artistic conception of the ＂overtones＂ of guqin musical aesthetics is actually derived from the artistic spirit of Taoist philosophy, as exemplified in Lao Tzu's statement: ＂existence and non-existence give birth the one to(the idea of)the other＂, and also in Zhuang tzu's essay on the ＂fasting of the mind＂, where he compared the hearing of the ears, the hearing of the mind and the hearing of the spirit. Zhuang tzu indicated that ＂let the hearing(of the ears)rest with the ears; let the mind rest in the verification(of the rightness of what is in the will), but the spirit is free from all pre-occupation and so waits for(the appearance of)things. ＂ The implementation of the Taoist ideas on guqin music is first to make the human's ears and mind to be balance and harmony, and then to allow the mind and spirit to achieve balance and harmony. Afterwards, people can play guqin music as long as they free themselves from the material world, and then they can experience the ＂overtones＂ of guqin music. Furthermore, the spirit of people could be wholly in unison with the harmony of the natural world; this forms the unique aesthetic value of guqin music. Finally, this paper takes a few phrases of guqin music: ＂Xiaoxiang Shuiyun＂ played by Wu Zhaoji as an example, in order to illustrate the deep meaning of ＂overtones＂ as they reflect the philosophy of Taoism.