得「意」忘「形」－－漢墓壁畫中天象圖的轉變過程研究

The Spirit Grasped and yet the Form Diminished – a Study on the Graphical Transformation of the Sky Charts in Mural Paintings of Han tombs

目前發現最早的墓室天象圖出現在漢代。從圖像內容看來，最早的西安交通大學壁畫墓的天象圖較為完整，且較具有科學意義。但是到了東漢晚期，天象圖中卻以各種仙人神獸為主，星點結構愈來愈難辨識，從中顯示出巨大的轉變。以往研究中較少將各階段圖像做比較，更少深入探究其中巨大的差異。本文在梳理相關考古資料之後，提出兩種原因造成圖像轉變。一是由於社會的變動：西漢是從貴族政治轉變到官僚政治的最後階段，爵位與俸祿、知識與經濟的關係變得更多元化，使得原本掌握在貴族手中的天文學題材逐漸被大眾所使用，卻由於知識面的不足，進而產生繪製時的誤解與疏漏。二是視覺心裡學的影響：相對於冷門的科學天文知識，大眾對圖像的追求以美觀、符合當時讖緯概念中的「天界」為主，使得「表現」的手法強烈，勝過「再現」的意義，因此神話題材便逐漸取代了原有的星座圖像，也從中衍生出幾何化的背景裝飾。整體圖像的出現到衰亡，正如歐陽修所言：「得其意而忘其形」。

Up to now, the earliest sky charts in China had been discovered in Han Tombs. Judging from the contents, the first sky chart mural discovered in the 'West Han Mural tomb of Xian Jiaotong University' owned a more complete feature with more scientific significance. However, a tremendous change in style and variation occurred when it came to the late Eastern Han Dynasty, when the immortals and mythological animals began to occupy the sky charts and the star installation could hardly been identified. In the past, not many researchers compared and contrasted the sky charts from all periods in Han Dynasty, not to mention the exploration of the significant differences. After probing into the archeological documents and data, this essay proposes two reasons regarding the transforming of the sky charts. The first is social change. Due to the shift from aristocracy to bureaucracy, the relation between the title and the salary, the knowledge and the wealth become more diversify, allowing the dissemination of astronomic knowledge and celestial themes that had been monopolized by aristocrats, the public began to gain access to related knowledge. Due to insufficient knowledge, there might have been inaccuracies in those sky charts. The second reason is the influences of visual psychology. Comparatively speaking, astrological knowledge was unknown to most people. Demanding aesthetics effects and complying with the conception of the 'realm of the heaven' in chien wei (a sect of Taoism), people represent instead of representation the sky in those charts. Therefore, mythological themes replaced the original observations of stars in those sky charts, from which geometrical decorations were derived. The appearance and the decline of the overall sky mapping can best be described with Ouyang Xiu's words: ' the spirit grasped and yet the form diminished.'