Wikipedia Article:
An accurate and concise definition of music is fundamental to being able to discuss, categorize, and otherwise consider the phenomenon of what we understand as being music. Many have been suggested, but defining music turns out to be more difficult than might first be imagined. As this article will demonstrate, there is ongoing controversy about how to define music.
The Oxford Universal Dictionary defines music as, "That one of the fine arts which is concerned with the combination of sounds with a view to beauty of form and the expression of thought or feeling" (Little and Onions 1965, 1300). However, the music genre known as noise music, for instance, challenges these ideas about what constitutes music's essential attributes by using non-traditional elements of music (Priest 2013, 132). (See also musique concrète.)
A famous example of the dilemma in defining music is John Cage’s composition titled 4'33. The written score has three movements and directs the performer(s) to appear on stage, indicate by gesture or other means when the piece begins, then make no sound and only mark sections and the end by gesture. This has form and other important attributes of music, but no sound other than whatever ambient sounds may be heard in the room. Some argue this is not music because, for example, it contains no sounds that are conventionally considered "musical" and the composer and performer(s) exert no control over the organization of the sounds heard (Dodd 2013). Others argue it is music because the conventional definitions of musical sounds are unnecessarily and arbitrarily limited, and control over the organization of the sounds is achieved by the composer and performer(s) through their division of what is heard into specific sections (Gann 2010).
Problems of defining music also arise from differences in the conception of music in different cultures.