藝術的跨界合作雖非新興的行為，近年來卻因各種內外在因素逐漸受到各界的重視。於此新氣象中，常被視為一門聽覺藝術的音樂，亦無可避免地在其表演素材、形態與風格等各方面，產生了莫大的改變，進而影響了既有的音樂學理。從音樂生態的供給端（創作、演繹）到接受端（欣賞、評論），傳統的音樂定義已無法貼切地體現當代音樂之跨界面向與意涵；從範疇的界定、思想的認知、型態的展現，乃至於詮釋權的釐清等，皆需被審慎思考。 根據包曼（Philip V. Bohlman)等學者所主張的音樂多元本體（multiple ontologies of music)觀點，音樂具有多元的可塑本質，音樂過程的參與者扮演著猶如詮釋者的角色。人們對於音樂的一切思維活動，最終目的在於對自我意識的彰顯與主權的控制；無論音樂如何被創作、演繹、欣賞與評論，人們對於音樂的認知，主要來自其本身與音樂之間的歷時或共時性互動有關。庫克（Nicholas Cook)亦強調：音樂學不僅反映音樂的實像，它更幫助形塑音樂。本文循音樂多元本體論的學理基礎，融合音樂界的觀點，探究當代音樂之跨界思維，進而討論現今諸多有關「跨界音樂」解讀之合宜性。

Though not new, cross-border cooperation in the arts has become increasingly valued by the viewing and listening public in recent years due to various internal and external factors. In this new atmosphere, classical music, which has always been considered as an auditory art, has made significant changes in its materials, shape and style, all of which affect existing theories of music. From the provider (composer, interpreter) to the recipient (audience, commentator), the traditional definition of classical music is no longer able to reflect the crossover inclination of contemporary music. Definitions of fields of performing, the core of cognitive thinking about the arts, and the authority of interpretation and establishment of aesthetic value all need to be reflected and reconstructed. However, can naming this kind of music “Classical Crossover Music” or “Crossover Music” truly and objectively reflect the real pluralism of contemporary music? According the multiple ontologies of music advocated by the American scholar Philip V. Bohlman, the ultimate goal for people in thinking about music is to highlight the self-consciousness and control over sovereignty. No matter how music is composed, interpreted, appreciated and commented upon, our cognition of music is mainly based on the historical and synchronic interaction between ourselves and the music itself. British scholar Nicholas Cook also stressed that musicology, in short, doesn’t just reflect practice; it helps mould it. Through the lens of the multiple ontologies of music, this paper blends interpretations from contemporary music, explores the cross-border actions of contemporary music, and then reviews the interpretative adequacy of “Crossover Music”.