# Programming Unconventional Computers: Dynamics, Development, Self-Reference

## Abstract

**:**

## 1. Introduction

## 2. Classical History and Unconventional Futures

**Figure 1.**Classical computation: the real world inspiration of human computers led to an abstract model, the Turing Machine. This was realised in hardware and exploited in software, and developed for 70 years, into a form unrecognisable to its early developers.

**Figure 2.**Unconventional computation: the real world inspiration of biological and other systems is leading to novel hardware. This must be abstracted into a computation model, and augmented with appropriate programming languages and tools. Seventy years from now, the technology will be unrecognisable from today’s ideas.

**Figure 3.**The wrong model: screenshot partway through a game of Not Tetris (http://stabyourself.net/nottetris2, accessed on 6 August 2012).

## 3. Computational Models as Abstractions of Physics

^{−15}[15]. The value of the mathematical constant π to 39 digits can give the volume of the observable universe to the nearest atom [16]. To measure π to more precision than this, we would need a measuring device bigger than the size of the universe. Despite this, π has been calculated to 10 trillion decimal places [17]: an impressive computation, but a completely physically unmeasurable value. Computational models need to be based on real-world physics: not only the laws, but also the practical constraints.

## 4. Inspired by Biological Modelling

Organic life exists only so far as it evolves in time. It is not a thing but a process—a never-resting continuous stream of events— Cassirer [18]

A process-centric description is arguably also needed in the context of emergence [20]. To summarise these ideas: “Life is a verb, not a noun.” [21].It must be a biology that asserts the primacy of processes over events, of relationships over entities, and of development over structure.— Ingold [19]

#### 4.1. Process

_{3}∈ X

_{2}∈ X

_{1}∈ X

_{0}, and cycles of membership, such as X ∈ Y ∈ X and even X ∈ X. So, for example, the NWF set with (valid) circular definition C = {t, C} “unfolds” to C = {t, {t, {t, …}}}.

#### 4.2. Dynamics

#### 4.3. Development

#### 4.4. Self-reference

## 5. Conclusions

## Acknowledgments

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Stepney, S.
Programming Unconventional Computers: Dynamics, Development, Self-Reference. *Entropy* **2012**, *14*, 1939-1952.
https://doi.org/10.3390/e14101939

**AMA Style**

Stepney S.
Programming Unconventional Computers: Dynamics, Development, Self-Reference. *Entropy*. 2012; 14(10):1939-1952.
https://doi.org/10.3390/e14101939

**Chicago/Turabian Style**

Stepney, Susan.
2012. "Programming Unconventional Computers: Dynamics, Development, Self-Reference" *Entropy* 14, no. 10: 1939-1952.
https://doi.org/10.3390/e14101939