Evolutionary Innovations and Where to Find Them: Routes to Open-Ended Evolution in Natural and Artificial Systems

Abstract

This paper presents a high-level conceptual framework to help orient the discussion and implementation of open-endedness in evolutionary systems. Drawing upon earlier work by Banzhaf et al., three different kinds of open-endedness are identified: exploratory, expansive, and transformational. These are characterised in terms of their relationship to the search space of phenotypic behaviours. A formalism is introduced to describe three key processes required for an evolutionary process: the generation of a phenotype from a genetic description, the evaluation of that phenotype, and the reproduction with variation of individuals according to their evaluation. The formalism makes explicit various influences in each of these processes that can easily be overlooked. The distinction is made between intrinsic and extrinsic implementations of these processes. A discussion then investigates how various interactions between these processes, and their modes of implementation, can lead to open-endedness. However, an important contribution of the paper is the demonstration that these considerations relate to exploratory open-endedness only. Conditions for the implementation of the more interesting kinds of open-endednessexpansive and transformational-are also discussed, emphasizing factors such as multiple domains of behaviour, transdomain bridges, and non-additive compositional systems. In contrast to a traditional Darwinian analysis, these factors relate not to the generic evolutionary properties of individuals and populations, but rather to the nature of the building blocks out of which individual organisms are constructed, and the laws and properties of the environment in which they exist. The paper ends with suggestions of how the framework can be used to categorise and compare the open-ended evolutionary potential of different systems, how it might guide the design of systems with greater capacity for open-ended evolution, and how it might be further improved.

An Overview of Open-Ended Evolution: Editorial Introduction to the Open-Ended Evolution II Special Issue

“…One Taylor provides some initial discussion of these questions in the final section of his contribution [37].…”

“…This enables open-ended dynamics to be observed for a while, until the limits of the space are exhausted. Formal aspects of this conundrum are discussed explicitly in the contribution of Taylor [37].…”

Self-Modifying Code in Open-Ended Evolutionary Systems

“…Open-endedness has been defined as the ability to continually produce novelty and/or complexity whereby novelty is classified into variation, innovation, and emergence (Banzhaf et al, 2016). Based on creativity research (Boden, 2015), different terms for this classification were suggested, namely exploratory, expansive, and transformational novelty, respectively (Taylor, 2019). The latter terms will be used here to avoid interpretation issues with innovation and emergence.…”

“…Regardless of the terminology, both definitions relate to a formal model and metamodel of the system under study. Exploratory novelty can be described using the current model, expansive novelty requires a change in that model but still uses concepts in the metamodel, and transformational novelty introduces new concepts necessitating a change in the metamodel (Banzhaf et al, 2016;Taylor, 2019). With their connection to model and metamodel, they provide a way to determine whether and which kind of nov-elty emerges in an open-ended evolutionary system.…”

Roadmap to Building a Cell: An Evolutionary Approach

“…As an alternative approach to the semi-rational evolutionary approach discussed above, one could choose to undertake a more exploratory, open ended, evolution. Herein, an intrinsic mechanism would be provided for the exploration of new state spaces by the system, thus allowing expansive and transformational evolutionary novelties (Banzhaf et al, 2016;Taylor, 2019). For example, new state spaces for exploration can be provided simply by modifying and re-engineering of the environment.…”