Classiﬁcation of Music Space from the Perspective of Information Philosophy †

: By reviewing the scope of domain division in information philosophy and correlating it with the classiﬁcation of music spaces, this study highlights the inadequacies of prior research on deﬁning music space types. The previous classiﬁcation of music space types neglected the signiﬁcance of spatial information as a crucial dimension in comprehending the characteristics and qualities of music spaces. Information philosophy proposes three characteristics of existence: objective reality, objective non-reality, and subjective non-reality. Music space, as a part of existence, can also be classiﬁed according to these characteristics. By reclassifying the types of music space, we can better understand the properties and attributes of each type.


Introduction
The emerging field of information philosophy encompasses both matter and information. This marks a significant shift in philosophical approaches in meta-philosophy, as it resolves the issue of communication and correlation between matter and consciousness, and holds great significance for tackling specific challenges within various branches of disciplines. This article presents an examination of the issue of music space. Music space differs from physical space as it operates on a distinct level of existence. Unlike plastic arts, which are composed of solid, stable, and sustainable spatial entities, the sound of music is fleeting, as the physical vibration wave quickly disappears, but its information can still be partially preserved. Therefore, the spatial dimension of music cannot be fully explained from a physical standpoint. The general classification of music space ignores its informational dimension. We have classified music spatial types in a new way through the dual-existence attributes of information philosophy. By distinguishing between objectivereality music space, objective-non-reality music space, and subjective-non-reality music space, the attributes and informational aspects of the types of music space are revealed.

An Overview of the Division of Existence Domains in Information Philosophy
Information philosophy has immense significance in meta-philosophy because it has dismantled the conventional concept of material and conscious existence that underpins traditional philosophy. It points out that there is no direct communication between matter and consciousness, and without the intervention of an information intermediary, there is a rupture between the two. Information philosophy has redefined the field of existence by proposing that existence is composed of matter and information. Matter has objective reality, while information has non-reality. Information consists of two layers; one is subjective information with subjective non-reality, which includes consciousness and the other is objective information with objective non-reality, which is the information manifested by the material itself [1] (p. 38). Information philosophy has divisions as depicted in Figure 1. This encompasses both the matter and consciousness that previously existed, while also by the material itself [1] (p. 38). Information philosophy has divisions as depicted in F 1. This encompasses both the matter and consciousness that previously existed, whil filling in a previous omission, which is the information reflected by matter itself, be matter itself cannot be directly recognized by us, but can only be recognized by the su through the information mapped by material itself through intermediary links.

Musical Space that Differs from that of Other Arts
Generally, when people discuss music, their initial perception is that music is th of time. Although nobody asserts that music is the art of space, it does not negate th that music encompasses space. Igor Fyodorovich Stravinsky said "The phenomen music is actually a phenomenon of thinking, and the purpose of thinking is guide sound and time. Without these two elements, music cannot be understood" [2] presentation of the sound of music in time requires the vibration of sound waves, w in a physical sense, have their spatial significance. The construction of spatial sound w relies on time to be completeed, so the time and space of music are unified and inse ble.

General Division of Music Space Types
1. After the spatiality of music is revealed, it is necessary to classify the types of m space. We can roughly divide music into two categories: internal relational spac external relational space. 2. First, the internal space of music, as the name implies, refers to the types of s related to the compositional elements of music, such as pitch space, harmony s formal structure space, rhythm space, melody space, tonality space, and so on. 3. Second, the external spatial relationships of music include a wide range of elem which can be roughly divided into the performance space, media space, aud space, and sound environment space. The performance space can be divided performance environment space and performance consciousness space. The m media space can be divided into music score carrier space, pronunciation instru space (the resonance cavity space of instruments directly affects the timbre and ume), and communication environment space (music hall, record playing s small chamber music, etc.). 4. Auditory space refers to the dynamic relationship between music and people, w a reciprocal interaction occurs between the musical works and the auditory pe tion of the subject. This space can be further categorized into cultural, metapho imaginative, and other dimensions. The external sound environment space ca

Musical Space that Differs from that of Other Arts
Generally, when people discuss music, their initial perception is that music is the art of time. Although nobody asserts that music is the art of space, it does not negate the fact that music encompasses space. Igor Fyodorovich Stravinsky said "The phenomenon of music is actually a phenomenon of thinking, and the purpose of thinking is guided by sound and time. Without these two elements, music cannot be understood" [2]. The presentation of the sound of music in time requires the vibration of sound waves, which, in a physical sense, have their spatial significance. The construction of spatial sound waves relies on time to be completeed, so the time and space of music are unified and inseparable.

1.
After the spatiality of music is revealed, it is necessary to classify the types of music space. We can roughly divide music into two categories: internal relational space and external relational space.

2.
First, the internal space of music, as the name implies, refers to the types of spaces related to the compositional elements of music, such as pitch space, harmony space, formal structure space, rhythm space, melody space, tonality space, and so on.

3.
Second, the external spatial relationships of music include a wide range of elements, which can be roughly divided into the performance space, media space, auditory space, and sound environment space. The performance space can be divided into performance environment space and performance consciousness space. The music media space can be divided into music score carrier space, pronunciation instrument space (the resonance cavity space of instruments directly affects the timbre and volume), and communication environment space (music hall, record playing space, small chamber music, etc.).

4.
Auditory space refers to the dynamic relationship between music and people, where a reciprocal interaction occurs between the musical works and the auditory perception of the subject. This space can be further categorized into cultural, metaphorical, imaginative, and other dimensions. The external sound environment space can be classified into two main types; one is music-centric with space as a supplement, such as theater music, and the other is space-centric with music as a supplement, such as ritual music, labor songs, ambient music in restaurants, etc. The types of music spaces summarized above are shown in Figure 2.

The Classification of Music Space Types in Information Philosophy
The overall categorization of the aforementioned music spaces may offer a basic comprehension of the relevant music space types; however, the characteristics and traits specific to each spatial type cannot be fully grasped. In addition to the space constructed by sound waves, music in time also has spatial types at the information level, for example, spatial information recognized by the subject. Specifically, a sound from weak to strong seems to give people a sense of space from far to near, but the sense of space from far to near here is not truly real space, but rather the spatial information of far and near. Therefore, we attempted to reclassify the above types according to the three levels of objective reality, objective non-reality, and subjective non-reality in information philosophy, as shown in Figure 3.

The Classification of Music Space Types in Information Philosophy
The overall categorization of the aforementioned music spaces may offer a basic comprehension of the relevant music space types; however, the characteristics and traits specific to each spatial type cannot be fully grasped. In addition to the space constructed by sound waves, music in time also has spatial types at the information level, for example, spatial information recognized by the subject. Specifically, a sound from weak to strong seems to give people a sense of space from far to near, but the sense of space from far to near here is not truly real space, but rather the spatial information of far and near. Therefore, we attempted to reclassify the above types according to the three levels of objective reality, objective non-reality, and subjective non-reality in information philosophy, as shown in Figure 3.
The previous explanation divides the existence domain into three parts: objective reality, objective non-reality, and subjective non-reality. "As the name suggests, 'reality' refers to the real existence of particles with a stationary mass". Information philosophy considers space to be an existence, because the space constructed by pervasive waves is real. In the realm of music spaces, there are concrete spaces, such as live performances in concert halls, which are objectively and tangibly present.
There are also non-physical spaces, such as the pitch space, which is not a physically extended space but rather a virtual space created in the mind through the objective information reflected by external sound systems. In this sense, pitch space is a non-reality space. Therefore, this article expresses spatial types in three domains: objective real space, objective non-reality space, and subjective non-reality space.
In objective physical space, there are performance environment spaces (such as concert halls and open-air theaters), communication media spaces (such as instrument resonators, music score carriers, and sound electronic devices), and external sound environment spaces. In the objectively non-reality spatial domain, the main focus is the internal space of music, including pitch space, harmony space, structural space, rhythm space, melody space, etc. These are non-real spaces presented through objective acoustical materials, which do not exist physically and do not conflict with or reject real spatial objects, but have a spatial structure and are recognized and accepted by people through the characteristics of information. The pitch of a musical sound is not the three-dimensional height of an object, but a phenomenon caused by the magnitude of the frequency of the sound wave vibration. Without the arrangement of highs and lows, music loses its fluctuations, its movement, and ultimately its sense of time. Similar elements such as harmony, musical form, rhythm, melody, and other spatial attributes are all objective non-reality spaces composed of sound materials. In the subjective non-reality spatial domain, there are spatial consciousness with performative awareness and auditory space, which are mainly nonreality spaces in consciousness. The performance itself needs to be situated within a certain space, which belongs to the category of objective reality, as mentioned in the previous classification. The key is that performance requires not only external space, but also internal consciousness space. We often find that accomplished performers have a highly developed inner awareness. And this spatial awareness will guide changes in behavior.

The Classification of Music Space Types in Information Philosophy
The overall categorization of the aforementioned music spaces may offer a basic comprehension of the relevant music space types; however, the characteristics and traits specific to each spatial type cannot be fully grasped. In addition to the space constructed by sound waves, music in time also has spatial types at the information level, for example, spatial information recognized by the subject. Specifically, a sound from weak to strong seems to give people a sense of space from far to near, but the sense of space from far to near here is not truly real space, but rather the spatial information of far and near. Therefore, we attempted to reclassify the above types according to the three levels of objective reality, objective non-reality, and subjective non-reality in information philosophy, as shown in Figure 3.  For example, in piano performance, expressive players often raise their entire body when playing high notes, as if all the cells in their body are rising up, and when playing low, somber melodies, their body tends to lower down or even bend over. Similarly, audiences who feel good about music often involuntarily move their bodies or tap their feet while listening, which are all expressions of spatial awareness during music performance or listening.
It is easy to see that denying the spatiality of music is equivalent to denying its existence, and there is no need to discuss a series of music activities under music spatial relationships such as performance, dissemination, and listening. As Wang Shaohua pointed out, "Negating the spatiality of music is obviously more harmful, more serious, and more difficult to accept than negating the temporality of other arts such as painting and sculpture. Air as an objective existence of matter and sound waves as fluid motion carrying energy must inevitably possess the basic properties of time and space and must inevitably provide an intuitive special spatial stimulus and spatial information during their self-operation" [3].
When it comes to the essence of music, Susanne K. Lange points out that "like all elements of art, musical elements are unreal things created only for the senses". Edward Hanslick properly expressed it as "the forms of musical movement". "The essence of music is a form of movement that is audible but not visible, meant exclusively for the ears and not the eyes" [4]. Faced with this form of movement that is audible but not visible, we often consider auditory art as temporal art and visual art as spatial art. However, not all spatial art is visible, and unreal spatial forms still have spatiality, which can be perceived through different sensory modes; for example, the size and weight of an object can be perceived through touch, and the distance and proximity of an object can be perceived through smell. The spatial perception experienced through music is virtual, such as hearing a series of sounds gradually increasing in volume and sequentially unfolding, as if an object is moving closer from far away. In this sense, space is visual, tangible, audible, and sensory, and all of these sensations require completion in time, so time and space are inseparable.
Audible time art has a conceptual spatial framework, and it is evident that spatial art must exist within time, with self-display achieved through information and achieving the condition of subject recognition.

Conclusions
Information philosophy has redefined the field of existence for traditional philosophy, shaking the foundations of traditional philosophy, and thus having a status of metaphilosophy. This new field of existence has resolved the problem of communication between matter and consciousness by proposing information as a medium to communicate between them. Therefore, the exploration of existence in information philosophy is established both on the ontological level and epistemological level. The nature of musical space is different from the durability of plastic arts, precisely because this unique characteristic shapes the richness of musical expression. Therefore, the exploration of musical space requires not only a discussion on the material level but also on the level of information. The new field of existence of information philosophy provides solid theoretical support for the classification of musical space types.