A definition of Reverse-Simulation Music founded on the three aspects of music
translated by Jean-Marc Pelletier

About the name and concept

Reverse-simulation music is a general term for specific phenomena,
that can include acoustic events, born of intentional human actions. An
important characteristic of reverse-simulation music is that human
actions are carried out according to sequences resulting from iterative
Reverse-simulation music was imagined as music of the kind that
perhaps had been once performed by the ancients or by primitive tribes
... or music that could have been performed by them (which we refer to
as "music that could have been"). At the same time, however, it is an
experiment in new music depending mainly on computer simulation-based
trials. Reverse-simulation music does not necessarily depend on
existing social structures related to music such as the distinction
between concerts, composers, performers and audience.
Furthermore, traditional music often conceals the origins and
underlying regulations of the sounds performed with notions of the
intuitive and spiritual. Reverse-simulation music, on the other hand,
rather seeks to expose them through the use of the aspect of "rule-based
generation" (logical computations); and, adding to it two other aspects
of "interpretation" and "naming," it defines itself through the concept
of those three "aspects."
The three aspects of music referred to in this definition can also
be applied to musical styles other than reverse-simulation, as they are
presented as a new conceptual point of view on the music of mankind.
However, requirements presented here like the use of iterative processes
are specific only to reverse-simulation music.
This experiment seeks to reverse the usual conception of computer
simulations. Rather than modelling within a computer space the various
phenomena of the world based on the laws of physics, phenomena that have
been verified within a computer space are modelled in the real world,
hence the name, reverse-simulation. This designation also alludes to
the modelling of "music that could have been," in other words the
recreation in the real world of events that likely did not actually take

About the three aspects of music

Each work of reverse-simulation music is regulated by the three aspects of メrule-based generationモ, メinterpretationモ and メnamingモ. Here, people who set the rules of the rule-based generation are referred to as designers; those who make decisions based on an interpretation are composers; and those who determine the names and origins used in the piece are namers. The act of actualising as action a work of reverse-simulation music in a manner defined by the interpretation is called the performance, and the people carrying out this performance are interpreters. The designer, composer and namer can be the same person.

Rule-based generation refers to an iterative system where computations are carried out based on the result of the preceding computation. Those calculations define the procedure (algorithm) carried out by the interpreter at the time of performance. This computation should preferably form a closed loop.

Interpretation is the act of determining how the computation results (sequence) borne of the rule-based generation is to be read by the interpreter and how the movement to the next computational step is to be carried out in a realistic fashion. In other words, it is the act of deciding the behaviour of the interpreter in response to each computation result, sorting out the details of the performance and designing the necessary tools for its execution. Furthermore, it includes the preparation of appropriate responses in case of mistakes by the interpreters at the time of performance.

Naming is the act of deciding the title of the work, the labelling of the rules, as well as the actions carried out by the interpreters and the identification of the objects used and furthermore includes the explanation of their メoriginモ. By doing this, naming seeks to register the reverse-simulation music piece in human society in the form of a unique story.

Requirements for reverse-simulation music in each of the three aspects

Rule-based generation:
Rules must be designed so that they can be computed and devised by anyone who doesnユt necessarily have advanced scientific knowledge (such as children or ancients), as long as are humans belonging to any sort of civilisation.
Rules must be such that they can be described using a logical language and must exclude any random or arbitrary decision.
In other words, if the computation results are the same at the start of the concert, the rest of the work must also be the same.
The computations performed by the interpreter must be independent and be such that they can be remembered.
Works of reverse-simulation music can sometimes have specific states defined at the start of the performance (in other words an initial state).

Interpretations should be such that anyone willing to devote their lives to practice should be able to execute them.
Interpretations should be devised in such a way that an observer should be able to clearly identify the different computation results.
Interpretations should be such that the characteristics and variety of all of the rule-based phenomena can be clearly perceived.
Interpretations should be devised so that interpreters can promptly and reliably carry out the calculations.
Interpretations can be influenced by the imagery of the names and origins.

The various names and origins defined by the namer can be imaginary neologisms.
Names and origins must reflect the characteristics of the rules and interpretations.
Names and origins can act to help the spectator and interpreter to understand and remember the work.
Names and origins can act to help setting up devices for the interpretation aspect.

Desirable Reverse-Simulation Music

Rules and interpretations that, through practice, can be carried out in a reflex-like manner are desirable.
Rules and interpretations where it is difficult for the interpreter to make mistakes are desirable.
Rules that are simple and lead to varied results are desirable.
Therefore, rules that cause the repetition of short punctual sequences are not desirable.
However, non-repetitive though characteristic rule-based phenomena are desirable.
Names and origins that are evocative and likely to be believed as true are desirable.
It is desirable to refer to or allude in the names and origins to the context and the people involved in the creation of the work of reverse-simulation music.

Reverse-Simulation Ensembles

A reverse-simulation ensemble is a performance group composed of several interpreters for the purpose of realising a piece of reverse-simulation music. Because normally a high level of training is required for an interpreter to single-handedly carry out rule-based calculations and the actions dictated by them, an ensemble where those tasks are split up and carried out in common between many interpreters is the most natural and desirable form for the realisation of reverse-simulation music.

Notated Reverse-Simulation Music

Ideally, reverse-simulation music is to be performed by carrying out rule-based calculations. However, in the advent that this should not be possible, performance can take place according to the notation of these calculationsユ results, as compiled in advance. This is not a desirable approach but in the extent that interpretation and naming are carried out according to rules, it can be considered as a possible field of reverse-simulation music.


● 概念と名称について





逆シミュレーション音楽における個々の作品は「規則による生成」、「解釈」、「命名」と名付けられた3つの「相」によって規定される。その際、「規則による生成」における規則を考えた人を「考案者」と呼び、 「解釈」における決めごとを考えた人を「作曲者」と呼び、 「命名」 における名前や由来を考えた人を「命名者」と呼び、「解釈」によって逆シミュレーション音楽を行為を通して実現することを「演奏」と呼び、この「演奏」を行う人を「解釈者」と呼ぶ。その際「考案者」、「作曲者」、「命名者」は同一人物であってもよい。

- 「規則による生成」とは、解釈者が演奏中に行う計算の手順(=アルゴリズム)をもとに、演奏中のある計算が、それよりもひとつ前に行われた計算結果に基づいて行われ、これを連鎖的に繰り返していくような、繰り返し計算システム全体のことである。また、このシステムにおける計算の連鎖は原則として閉じた環を形成しているものとする。

- 「解釈」とは 「規則による生成」によって生み出される計算結果(数列)を解釈者がどのように読みとり、また次の計算ステップにどのように受け渡すかを現実的に定めることである。つまり個々の計算結果に対応した解釈者のふるまい方や演奏の準備、そのために使用される道具等に関する工夫のことである。さらに解釈者が演奏時に犯すかもしれない誤りに対する対処法もこれらの工夫に含む。

- 「命名」とは作品タイトルや規則の名前、解釈で行われる行為、使われる物などに名前を与えることであり、またそれらの「由来」を解説することを含む。 命名は逆シミュレーション音楽作品を固有の物語に位置づけ人間社会に登録することである。

● 3つの「相」における「逆シミュレーション音楽」の条件
規則は高度な科学的知識を持たない人々(例えば子供や古代人)でも、文明を持つ地球上の人類ならば、 計算可能かつ考案可能だと思われるものでなくてはならない。
つまり、 計算の結果は演奏開始の状態が同じならその後も常に同じになるようなものでなくてはならない。


名前や由来は 規則や解釈によって定められた決めごとの特徴を反映していなくてはならない。
名前や由来 は解釈者や鑑賞者が作品を解釈し記憶する手助けになることがある。
名前や由来 は 解釈における様々な工夫の手助けとなることがある。

ただし反復ではない、 規則によって引き起こされる特徴的な現象は好ましい。
名前や由来 はイメージしやすく、事実と信じられるものが好ましい。


本来の逆シミュレーション音楽は 規則による計算をしながら演奏を続けるものであるが、それが現実的に不可能な場合、あらかじめ計算の結果を記譜し、それに従って演奏を行うことがある。これは本来好ましくない逆シミュレーション音楽ではあるが、 規則に従い解釈と命名が行われている限り逆シミュレーション音楽のひとつの領域である。