摘要
本文主要是從字源學角度，並輔以古代字書與注疏家的資料，論證「中庸」之所以為「不偏不倚」「恰到好處」之義，乃因具備了音樂的「和諧」之特性。「和諧」為音樂的基本要素及最大特色，儒家不但於樂教中強調人群社會的音樂性「和諧」作用，也於個人德行的「中庸之道」中顯示音樂性的「和諧」。本文追溯「和」「中」「庸」三個字在本質上都具有音樂性的「和諧」之義。其中「和」及「庸」都與樂器有直接關係；「中」字雖與樂器無關，卻也被古代許多注疏家賦予「和也」之義。而音樂的「和」係來自於樂音之間的「節度有序」。因此當「中庸」從「音樂性」之「和」轉而為「德行」之「和」時，便從聽覺的美感，轉而為行為舉止的「恰到好處」。這中間既有音樂的感性，又有音樂的理性，確實稱得上是「不偏不倚」。
並列摘要
This article employs the etymological method and makes use of the data of commentaries on a variety of classics to argue that the ”doctrine of the mean” exhibits the character of harmony in music. In ancient China, Confucian philosophers put emphasis on the harmony in society as well as in personal moral cultivation. All these demonstrate the nature of harmony in music. We trace the origins of the three characters 和, 中 and 庸 and indicate that all these three characters convey the implications of musical harmony. The harmony in music is made possible by the order of musical notes. Therefore, it is understandable that the shift from musical harmony to moral harmony results in the order of one's behavior. Every action has to be in good order. In sum, the doctrine of the mean comprises the sensibility and rationality as in music.