Analysis from Simplification to Interactivity in John Cage’s 4’33” and Philip Glass’s Metamorphosis Based on Jonathan D. Kramer’s Theory

: The postmodernist musical works reflect the uncertainty, fragmentation, irony, and carnival of postmodernism, and some of them also embody the characteristics of simplification and interactivity. In this paper, John Cage’s 4’33” and Philip Glass’s Metamorphosis will be compared and analyzed with Jonathan D. Kramer’s theoretical view, to research the simplification and interactivity of the reasons, as well as the musical and social significance. Simplification is one of the prerequisites of interactivity. The simplification of Glass’s Metamorphosis accounts for the simplification or even elimination of musical elements, but the emotions and meanings expressed in the works are not affected. It leaves a broader imagination, which is where the interactivity arises. Postmodernist music composers use simplification skills to resonate with listeners who the social environment and postmodernist values have influenced in their works. The “blank left” of postmodernist music works gives the audience reasonable space for integration, and the willingness of the postmodernist audience to actively participate in the work does not limit the work to unilateral output and complete acceptance by the other side. This interactivity also creates a broader range of possibilities.


Introduction
As early as the middle of the 20th century, postmodernist music was born with a style of antirationality, disorder, and fragmentary sense, different from modernist music. In 1999, Jonathan D. Kramer published his theory on postmodernist music, The Nature and Origins of Musical Postmodernism, which explained his understanding of the origin and characteristics of postmodernist music. His views on postmodern music originated in the mind of the audience1 and other aspects are helpful for the research of this essay [1]. Also, Kramer lists sixteen characteristics of postmodern music in his theory, and argues that these characteristics should not be used as a checklist to determine whether a musical work is post-modern, because not only are there not many works that embody all of these characteristics, but it is also difficult to say that a work does not have any of these characteristics. Thus, "postmodernist music is not a neat category with rigid boundaries2".
There have been several theses on the characteristics of postmodernism, or what postmodernism is. The characteristics of postmodernism are universal in various types of works, so postmodernist music also presents these characteristics. Ihab Hassan(1982) compared some concepts of postmodernism and modernism in the way of binary opposition, showing the characteristics of postmodernism3, such as uncertainty, chaos, and non-principle [2]. Kramer(1999) proposed the unity, intertextuality, and eclecticism of postmodernist music. 4 While many characteristics of postmodernist music have been discussed before, however, there is still a gap in the research on the simplification and interactivity of postmodernist music. John Cage's 4'33" and Philip Glass's Metamorphosis can be used as unique representative music works to help show the characteristics of postmodernist music in this aspect, and Kramer's theory can be used to help explain. At the same time, this essay will explore the reasons and significance of these characteristics. Therefore, this essay will draw on Kramer's theory to mainly argue the special application and significance of simplification and interactivity in postmodernist music. This paper will be divided into three parts. The first part will talk about the simplification of Philip Glass's Metamorphosis and John Cage's 4'33". By analyzing the similarities and differences between John Cage's 4'33" and Philip Glass's Metamorphosis, this part will point out the embodiment of simplification, which is one of the preconditions of interactivity. The second part will focus on the interactivity of Philip Glass's Metamorphosis and John Cage's 4'33". By analyzing the two musical works, this part will show the meaning and causes of interactivity based on the theories of Kramer and Kenneth Gergen. The third part will elaborate on the significance of simplification and interactivity in postmodernist music, including the musical and social significance of simplification and audience integration based on Kramer's theory.

The Simplification of Philip Glass's Metamorphosis and John Cage's 4'33"
One of the preconditions for musical interactivity is the simplification. The various simplifications made by the composer give the audience a suitable space to integrate into the works, and the different simplification skills bring broader imagination space in the resulting "blank left", thus promoting the emergence and development of musical interaction. Therefore, it is important and necessary to first explain the simplification of musical works. Philip Glass's Metamorphosis and John Cage's 4'33" embody different but typical approaches to simplification.

Repetition of Simple Musical Elements in Philip Glass's Metamorphosis
Philip Glass's Metamorphosis belongs to Minimalist Music, an art form that uses only limited or minimal musical material in its music. Minimalist music was born in the 1960s. In 1968, Michael Nieman first developed and deduced the "minimal-music" character, which is a form of music that uses only a limited amount of material, and later expanded his definition to minimalist music [3]. 5 Another minimalist musician, Tom Johnson(1989), described minimalist music this way, "It includes any music written using very little or restricted material: music that uses only a minimal number of notes, a minimal number of words, or is written for only a few instruments." [4].
In 1988, Philip Glass released the musical composition Metamorphosis, which was written for the documentary film The Thin Blue Line and takes its title from the novel of the same name by Jewish novelist Franz Kafka, Metamorphosis, and used the plot of the novel as its subject matter. The novel Metamorphosis describes the change of the protagonist Gregor Samsa before and after his transformation into a beetle. The novel is divided into three parts, from Gregor's hard work to earn money and getting respect from his family before he becomes a beetle, to the family's view of him as a burden after he becomes a beetle and loses his labor force, and finally the death of Gregor, who is starving and cold in a cold and uncaring family, while the family is celebrating their release from the burden. The novel shows the tragic fate of those living at the bottom of society and reveals the profit-oriented and indifferent nature of people under capitalist oppression. And The Thin Blue Line, completed in 1988, tells the true case of Randall Dale Adams, who was sentenced to death for committing murder. The plots of both the novel and the documentary reflect the emotions Glass wanted to express when he created Metamorphosis.
Metamorphosis is a soothing yet undulating and violently turbulent piano piece, characterized by a cyclic repetition of similar notes and melodic combinations. The work has five movements, in which the smaller units of figure, motif, and cell are repeated over and over again, as well as both the overall melody and the detailed melody embody repetition: the first overall melodic repetition takes place at 1:35 in the first movement, followed by a second repetition at 4:45. The second movement has a different melody, but remains a repetition of a few notes and combinations of notes. A different rhythm appears at 9:15, faster than before, and these faster melodies are also repeated later. Similarly, the third and fourth movements are melodically different, i.e. not simply repetitive, and the rhythm of the fourth movement presents a uniqueness that distinguishes it from either of the other movements. Finally, the fifth movement returns to the same placidity as the first. 6 From the score, it can be noticed that Glass is making a simple, condensed treatment of the melody and harmonic patterns of Metamorphosis, using fewer types of chords and a simplified chord structure. For example, Figure 1 shows an excerpt from the score of the second movement, which uses elongated and repeated simple melodies to present a quiet and gentle atmosphere. Figure 2 also shows multiple repetitions of a simple melody. Figure 3 reflects the musical characteristic of repetitive rhythms during harmonic connection. Table 1, by summarizing the chord series in the five movements, reflects that the chord technique in Metamorphosis is relatively simple, mainly I III VI [5]. 7    These show that the simplification of Glass' Metamorphosis is characterized by simple melodies, rhythms, and chord repetitions.

Lack of Musical Elements in John Cage's 4'33"
Influenced by Eastern philosophical ideas [6], 10 in 1952 John Cage released 4'33", a piece of music that is so special that it is silent throughout, unlike all the past music. This piece has had several performances, such as the Daniel C. version, the BBC channel broadcast, and the version played by the Berlin Philharmonic in 2020. The live performers remained quiet throughout, turning the score only at the end of each of the prescribed three movements. It is impossible to argue with the fact that although 4'33" has been controversial because of its unique musical form, it is a bold experiment that is in line with the Chinese classical culture of "no sound is better than sound", and in a way represents the development of a new concept.
The simplification of Glass's Metamorphosis is mild, while that of Cage's 4'33" is extreme. In a sense, Cage's 4'33" can be seen as an extreme "simplification" of the composer's expression, so that it is completely silent, like its score ( Figure 4). "Tacet" is a musical notation that means quiet. The score indicates that all three movements should keep quiet, missing basic elements such as the pentatonic, notes, and rests. But for Cage, 4'33" is not silent while the performance is in progress. The chatter of the audience, the clash of chairs, etc. are all "music". According to him, "If art is to be of benefit to mankind, it should not separate from life. The artist's task is to make their audience pay attention to the beauty 10 The viewpoint is from Hu Yuan, "Indian philosophy and John Cage's music creation." 11 Source of music score: https://www.sin80.com/score/5d69f7be?ivk_sa=1024320u of everyday life, not to the artist's performance." 12 This means that the meaning of this "completely silent" work is still complete, serious, and important, and is not rendered meaningless by the "absence" of musical elements. This simplification is thus important for the restoration of musical ontology and the affirmation and promotion of human subjectivity and self-worth [7]. 13

Comparative Analysis of Simplification in Philip Glass's Metamorphosis and John
Cage's 4'33" Obviously, the differences between John Cage's 4'33" and Philip Glass's Metamorphosis lie in their musical content and musical form. Unlike Cage's 4'33", which is extremely silent, Glass's Metamorphosis has real music playing. In addition, Cage's 4'33" has a more flexible player, who could be a pianist or a symphony orchestra. Glass's Metamorphosis, on the other hand, is performed by a single piano player due to the fixed nature of the score. Yet there are also similarities between the two works. In a sense, they both represent a simplification of musical composition, both in terms of the "blank left" of the composition and the simple repetition of the melody. At the same time, minimalism leaves the complexity of modernism and is similar to postmodernism, which means that both John Cage's 4'33" and Philip Glass's Metamorphosis can help reflect the characteristics of postmodernist music effectively. Thus, the two works are comparable and can show some features together.
Glass's Metamorphosis embodies a simplification of melody, rhythm, and chords, while John Cage's 4'33" shows a "purging" of melody, rhythm, chords, and other musical elements. However, by introducing and understanding the context in which the works were composed, the audience can get no less information from the works. Even though Metamorphosis is simple, it fully expresses the influence and emotion brought to Philip by The plot of Kafka's Metamorphosis and the documentary The Thin Blue Line; while Cage's 4'33" is silent, it embraces all the sounds of the scene during the performance, which gives the work itself irreducible and diverse possibilities.
Therefore, simplicity, repetition, and deletion affect the content of the music and the form it takes, but not the emotion and meaning it intend to convey.

The Interactivity of Philip Glass's Metamorphosis and John Cage's 4'33"
After explaining the simplification of Philip Glass's Metamorphosis and John Cage's 4'33", the musical interactivity embodied in these two works can be fully explained. In these two works, the interactivity of John Cage's 4'33" is more fully reflected and easier to understand. Therefore, 4'33" will be introduced first, and then the interactivity of Metamorphosis will be further explained based on the existing understanding.

Audience Integration Completes the Content and Meaning of John Cage's 4'33"
In The Nature and Origins of Musical Postmodernism, Kramer believes that postmodernism is an attitude. Postmodernism comes from the minds of today's listeners rather than from history or the past. As he writes, "It is in the minds of today's listeners, more than in history, that we find clues to the sources of postmodernism. It comes from the present-from ourselves-more than from the past.", Composers and listeners who are influenced in some extent by the social environment find resonance in musical compositions that reflect postmodern attitudes and practices 14 . Through listening and feeling, the audience tends to get a different understanding of postmodernist music. "This understanding of postmodernism, as a relationship between a listener and a piece instead of a characteristic of a music work, tills the fertile ground [8]." 15 John Cage's 4'33" is a good example of interactivity. Its controversy stems from whether such complete silence makes sense. Some people think it is absurd, almost like "the Emperor's New clothes". But it is different and will make sense.
Lots of comments 16 on this work can be seen on social media, as well as many articles on its analysis and thinking. Tudor called it "one of the most intense listening experiences you can have". One comment left only a few lines blank, like the performance itself. Someone said, "This is the same thing playing backward and forwards? No. It's different every time you listen to it." Some even said they cried after hearing it. While as to how to understand it, many people have their own opinions. Someone thinks that it can be interpreted as accidental music. The work breaks the boundary between the sound of the performance and other sounds in the scene, and the sound of each performance is different. This is in line with Cage's concept that Everything is music. Some think that this kind of silence is deliberately artificial. John Cage made a series of designs including performance space, setting up piano, beginning and ending moments, and creating atmosphere, all of which give meaning to silence. Some people think that the meaning of silence needs to be valued. "The piece, I think, can most use-fully be seen as a tribute to the experience of silence, a reminder of its existence and its importance for all of us [9]." 17 Those who evaluate and analyze are the audience of the work. According to the video of the performance, the camera was only given to the performers on the stage, but the applause heard in the video proved that there was an audience, and the people watching the video were also the audience. Inevitably, the audience will have different feelings and musical understandings depending on their mood and surrounding environment. In the face of such works, the audience's feeling has become an important factor to determine the meaning of the works. From start to finish, and after, all the feedback from the audience gives it real meaning or no significance at all.
For some listeners, the silence is actually meaningless, because resonance requires a two-way choice between composer and listener. The work in question is like "Schrodinger's cat" in a sense, and the audience is the one who opens the box and sees the cat through his own eyes. Therefore, it is the participation of the audience and their opinions that give the work complete meaning.

Interactivity Generated by Imaginative Space in Philip Glass's Metamorphosis
The composer of minimalist music does not simply simplify the music, the notes, but gives the music more imagination, which makes it more attractive. The simplicity of the melody creates more space, making the music itself less concrete and formal, and giving the audience the freedom to "recreate" and imagine it. Compared to past genres, minimalist music is much less narrative and requires more listening, perception, and imagination on the part of the listener. It is also here that interactivity occurs.
For listeners who do not know the background of the composition, listening to such a piece of simple melodic music is more likely to trigger different feelings and imagination. Some comments and understandings 18 about Glass's Metamorphosis are also collected from the audience on the Internet. Someone feels that it is calm and powerful; someone indicates that it is the perfect reading music; someone comments that it "rises and falls together, unruffled and echoing reality."; and someone thinks that "Metamorphosis is simple, yet haunting, stirring, and emotional, blending 15  elements of Glass's minimal ideals to form a suite that is ever-changing."; and someone imagines when the next melody and rhythm that breaks the repetition will come. And as mentioned above, the simple melody of repetition allows the listener to treat it as background sound, allowing more room to imagine or add their own actions. It can also be used by listeners as part of something else.

Features and Reasons of Interactivity in Philip Glass's Metamorphosis and John Cage's 4'33"
Simplification is, in a sense, one of the prerequisites for interactivity. Traditionally, the audience is the passive recipient of the musical work, who just needs to sit down and listen, appreciate and savor the content of the musical work. However, in the face of simplified works, the audience's original roles in this relationship may change. The simplification of postmodernist music, as a "blank left" of the connotation of the work, allows the audience to have a reasonable space to blend in. The listener's response gives repetition richer meaning, and the simplified music allows the listener to become part of it. Whether it's Cage's 4'33" or Glass's Metamorphosis, they show a kind of "blank left" feature, which requires the participation of the audience and also attracts the audience to participate in perfecting the work. In the traditional sense, music is more dependent on the expression of the composer. However, as Kramer thinks that postmodernist music comes from the mind of the audience and relies on the resonance of the audience, this unique relationship makes some postmodernist music have a more profound and special significance, and the existence of the audience and response refer to the development of interactivity. Eventually, this kind of interactivity is accomplished when the composer and the audience resonate in the composition.
Therefore, the role of the audience in postmodernist musical works symbolizes the completion of interactivity. It is not a behavioral interaction limited to the performance scene but abstractly become a conceptual interaction. Conceptual art, which derives from Marcel Duchamp's idea 19 that "an artwork is fundamentally an artist's idea, rather than a tangible object, namely painting and sculpture; Tangible things come out of that thought", can be used as a reference to understand this interactivity. "Conceptual art frequently reflects on meaning through the process of fabrication rather than a representation of the finished art object." [10]. For some postmodernist music, not only the composer expresses himself in the creation as in the past, or embodies his thoughts in a musical work, but also the audience becomes a part of the work. The audience who finds resonance in the work with the composer completes the expression of the connotation of the work together, and even they become the participants in the creation of the work. Like John Cage's 4'33", the "Tacet" score does not seem to prove what it is without the audience. But in a live performance, for instance, when the silent piano is watched and "listened to" by the audience, is it nothing? The answer is not an outright "no". The understanding from the audience determines what it is, and the audience who find resonance in it carries out some kind of "conceptual interaction" with the composer, and finally completes the work by both sides.
The reasons for the interactivity can be attributed to two aspects: the simplification of composers and the influence of the social environment. The first is the simplification skills the composers use. Minimalist music should be noticed, and Philip Glass's Metamorphosis is one of them. Similarly, John Cage's 4'33" can also be thought of as such a complete simplification that it is silent. While simplification does not mean just "simply", the composer does achieve an effect that appears to reduce expression through a variety of skills, including the reduction of musical material and repetition. Less expression on one side means that the other needs to respond. Post-modern audiences are interactive when confronted with simplification.
This response is not only due to the simplification of composition but also due to the influence of the social environment. Kramer discusses Kenneth J. Gergen's concept of social saturation in his theory 20 . Too much information leads to fragmentation, with people constantly receiving these messages competing for their attention, and too much vocal expression making people increasingly aware that the objects they are talking about are "products of perspective 21 " [11]. Such a state encourages the habit of construction and reconstruction. So when confronted with some things, including works of art, conceptualizing them becomes the norm. Perhaps influenced by such environment and values, people tend to unconsciously bring their own perspectives and emotions, which promotes the emergence of interactivity. It is also impossible to rule out the influence on composers, who may understand and use such psychology of the audience to construct the interactivity in the work.
In conclusion, in the face of the simplification of music creation, the audience of postmodernist music is willing to participate actively, so that the work is not limited to one side's output and the other side's complete acceptance, and this kind of interactivity reflects resonance and creates more possibilities. This is the characteristic of interactivity reflected in postmodernist music.

The Significance of Postmodernist Music Simplification and Interactivity
The study of simplification and interactivity in postmodernist music has important implications for both music itself and society. Simplification and interactivity not only bring a new concept to the development of music, but also have an impact on the artistic values of society.

The Musical Significance of Postmodernist Music Simplification and Interactivity
The musical significance of the simplification and interactivity of postmodernist music can be summarized from three perspectives: the works themselves, the musical characteristics, and the influence on other musical genres.
On the one hand, the simplification and interactivity embody in some postmodernist music works help free the meaning and expression of the works from their limitations. The use of simplification techniques to construct a "blank left" was not pioneered by musical works, but its application unintentionally contributed to the development of a different kind of musical aesthetic. For example, the use of simple words in literature can bring readers closer to the work, because plain and straightforward words are better understood and more realistic as well as easier to imagine. While in paintings and architecture, the reduction of color and the blank space outside the subject can better arouse the curiosity and imagination of the viewer. Similarly, simplification in musical works enhances this interactive nature of engaging the listener's imagination, which allows the creator to relinquish some of the initiatives to the audience. Audiences from different cultural backgrounds and environments spontaneously generate their own interpretations of the meaning of the work. This diversity of interpretations, which is more casual, popular, and universal, is not exactly the same as "a thousand people have a thousand Hamlets 22 ".
On the other hand, the interactivity of the work and the audience's echoing of the completion of that interactivity also help to embody some of the characteristics of postmodernist music. As Kramer argues, postmodernist music exhibits several characteristics, including a lack of respect for boundaries between sounds, an embrace of contradiction, fragmentation, pluralism, and the display of multiple meanings. 23 For example, boundaries are broken during interaction and multiple meanings are given after the interaction. A postmodernist musical work can be seen as divided into many parts, partly from the context of its time, partly from its creator, and partly from the future, that is, the audience's reaction to and understanding of it. Interactivity foreshadows the need to establish a twoway relationship in which the audience plays the role of participant or even completer. The uncontrollable will of the audience means that there are more possibilities for the meaning of the work, leading to more diverse directions of development.
In addition, interactivity has been a revelatory aid to the development of modern popular music. Simplification and interactivity imply a break with the old creative thinking, pushing the innovation of music creation while impacting traditional music. The breaking down of musical boundaries has made the audience's feelings more important than ever. Although the expression of the composer still comes first in the accomplishment of interactivity, for the creation of music is the source of the listener's attitude, it is irrefutable that the role played by the audience in the musical work is given more importance. Thus we can assume that the embodiment of interactivity implies an increase in the importance of the audience. Then, due to the justified existence of demand, popular music that values audience feedback, or arguably serves the public and profits from popular favorites, has developed as never before, prompted by a variety of reasons, and the existence of interactivity foreshadows and fuels this trend.

The Social Significance of Postmodern Music Simplification and Interactivity
The social significance of this simplification and interactivity focuses on social art values. Kramer argues that many postmodernist composers embraced conflict and contradiction, and that postmodern listeners preferred to accept each piece of music rather than as a whole. 24 At the same time, postmodernist music is more distinctive and seems less inclusive, but the interactivity it embodies is noted as a monolithic element. The creator and the listener have in a sense reached a balance, which means that the audience has become more important than in the past. This increased importance of audience has further developed in the context of globalization, contributing to the advancement of mass art, which in turn has accelerated the trend toward the popularization of art and the pursuit of wonderful things in everyday life.
Social art values are also more reflective of pluralism and tolerance. The popularization of art generated by interactivity means that anyone from all walks of life can be the object of an artwork. The blossoming of art and the variety of audiences form a "many-to-many" relationship that not only allows any worthwhile work to find its audience, but also requires a larger audience to increase its tolerance of art. One reason, or one way, that audiences can become more tolerant is that artworks can be accepted not as a whole, but as a part of something meaningful. Influenced by such social art values, artworks also have more possibilities, which in turn creates a virtuous circle.

Conclusions
Using John Cage's 4'33" and Philip Glass's Metamorphosis as comparative examples, this paper applies Kramer's theory to analyze the simplification and interactivity embodied in postmodernist music. The object of simplification is the melody, rhythm, chords, and other musical elements of a piece of music, while the meaning of the piece retains. Such simplification techniques allow for a reasonable space for audience integration, while, in conjunction with Gergen's theories on social saturation, individual ideas gradually move from unity to diversity, and the postmodernist values influenced and developed by the social environment make listeners hope to find resonance in musical works that reflect postmodern attitudes and practices. As a result, the interaction between composer, work, and audience is created and demonstrated. The simplification and interactivity embodied in postmodernist music have both musical and social implications. Simplification facilitates audience inclusion, and this interactivity allows for a more diverse understanding of the work. At the same time, simplification and interactivity also helped to embody some of the other characteristics of postmodernist music, such as the breaking down of boundaries. In addition, interactivity has helped drive the trend toward modern popular music. In terms of social significance, simplification and interactivity accelerated the popularization and mass appeal of art.
Overall, the composer's simplification skills and social saturation influenced the need and willingness of audiences to participate in postmodernist music, so that musical works were not limited to one-sided output and complete acceptance by another side. The composer's "blank left" in the work allows the listener to participate in the co-creation of the work, thus achieving a sense of empathy. The audience may be influenced by several factors in the process of appreciation, and this has a greater impact on the meaning of postmodernist music than in the past due to the interactive and co-creative nature of the work, which in turn heralds the opportunity for a wider range of possibilities. In postmodernist music such as Class and Cage's works, the audience is not only the listener, but also a participant in the creation of meaning, making the meaning of the music more varied, deeper, and unique through interactivity.