生死輪圖像的水車起源及其在大乘佛教裏的演變

生死輪是佛教藝術裏的一種特殊的輪形圖案，用來表現佛教的世界觀、生死觀、因果思想等。對於生死輪這種圖像的形制，小乘一切有部的戒律《根本說一切有部毘奈耶》裏有詳盡的描述。同時，這種圖像的各種變形還出現在以大乘（包括密宗）為主導的東亞、中亞的廣大地區。那麼，生死輪圖像最初到底是指一種什麼輪子呢？大乘佛教與小乘佛教殊異，在廣大的大乘佛教地區出現的生死輪與原小乘戒律裏的描述，又有什麼根本性的不同呢？本文從文獻和圖像分析兩方面論證，生死輪這種圖像的構圖原型與水車休戚相關。水車的歷史很複雜，在中西歷史上的各式各樣的水車之中，本文認為生死輪這一圖像原來所借喻的是印度手推式的noria式水車。同時，有水車特徵的生死輪圖像在漢文化區的出現又與中國的筒車的推廣有關。按照漢譯的《根本說一切有部毘奈耶》的描述，生死輪外緣應繪一圈盛水器。在現存的較早的生死輪圖像中，有三個地方的圖像繪有這一標誌。本文提出生死輪上的這些盛水器可能就是代表生死輪迴過程裏的中有階段。最後，本文探討生死輪的各種主要演變形式。這些演變說明大乘佛教對佛法、輪迴世界、解脫之路、佛陀觀的不同理解。

關鍵字

生死輪；水車；筒車；一切有部；大乘演變

並列摘要

The wheel of life (samsāracakra) is a special iconographic wheel shape found in Buddhist art. It represents the Buddhist view of the cosmos, life, and causality. The vinaya of the Sarvāstivāda, a Hinayāna school, provides a detailed structural description of the wheel of life image. In the same time period, variations of this iconography appeared within the areas of East Asia and Central Asia where Mahayana Buddhism (including Tantric Buddhism) was dominant. One might ask what was the original model for the samsāracakra wheel? Mahayana Buddhism and Hinayāna Buddhism can be quite different in doctrine and so a more fundamental question might be: What are the fundamental differences between the images of the wheel of life that appeared in the regions influenced by Mahāyāna Buddhism and the descriptions of this iconography in the Hinayāna text? Based on studies of related literature and an analysis of visual images, this article proposes that the configuration of the iconography of the wheel of life had its origin in a waterwheel. Taking into account the complicated history of waterwheels throughout the world, this article suggests that the image of the wheel of life initially referred to the manual noria type of waterwheel found in India, and in addition, that the emergence of the images of the wheel of life in China was related to the wide-spread use of the Chinese style waterwheel, namely the tongche. According to the description in the Chinese translation of the Mūlasarvāstivādin-vinaya, water containers were positioned along the rim of the wheel. Among the existing images of the wheel of life, there are depictions of these water containers representing three different areas of the world. This article proposes that these water containers, positioned along the rim of the wheel of life, may represent the intermediate after-death stage called zhongyou, or antarābhava. In addition, this study will consider certain major changes in the iconography of the wheel of life. These changes point to the variant interpretations in Mahayana Buddhism of the Dharma, the world of samsāra, the path of liberation, and Buddha's views.