is that it makes narratives out of musical worlds that often seem to lack them". Music can be divided into different genres in several ways. The artistic nature of music means that these classifications are often arbitrary and controversial, and some genres may overlap. There are several academic approaches to genres. In his book Form in Tonal Music, Douglass M. Green lists madrigal, motet, canzona, ricercar, and dance as examples of genres from the Renaissance period. According to Green, "Beethoven's Op. 61 and Mendelssohn's Op. 64 are identical in genre – both are violin concertos – but different in form. However, Mozart's Rondo for Piano, K. 511, and the Agnus Dei from his Mass, K. 317 are quite different in genre but happen to be similar in form." Some, like Peter van der Merwe, treat the terms genre and style as the same, saying that genre should be defined as pieces of music that share a certain style or "basic musical language". Others, such as Allan F. Moore, state that genre and style are two separate terms, and that secondary characteristics such as subject matter can also differentiate between genres. A music genre or subgenre may be defined by the musical techniques, the styles, the context, and content and spirit of the themes. Geographical origin is sometimes used to identify a music genre, though a single geographical category will often include a wide variety of subgenres. Several music scholars have criticized the priority accorded to genre-based communities and listening practices. For example, Laurie argues that "music genres do not belong to isolated, self-sufficient communities. People constantly move between environments where diverse forms of music are heard, advertised and accessorised with distinctive iconographies, narratives and celebrity identities that also touch on non-musical worlds." Popular culture and other media The concept of genre is often applied, sometimes rather loosely, to other media with an artistic element, such as video game genres. Genre, and numerous minutely divided subgenres, affect popular culture very significantly, not least as they are used to classify it for publicity purposes. The vastly increased output of popular culture in the age of electronic media encourages dividing cultural products by genre to simplify the search for products by consumers, a trend the Internet has only intensified. Linguistics In philosophy of language, genre figures prominently in the works of philosopher and literary scholar Mikhail Bakhtin. Bakhtin's basic observations were of "speech