# Assembly Theory Explains and Quantifies the Emergence of Selection and Evolution

**Authors:** Abhishek Sharma, Dániel Czégel, Michael Lachmann, Christopher P. Kempes, Sara I. Walker, Leroy Cronin  
**arXiv:** [2206.02279](https://arxiv.org/abs/2206.02279)  
**Date:** 2022-06-05  
**Summary page:** https://www.summarizepaper.com/en/paper/2206.02279v3/

## Key points

- Scientists have struggled to reconcile the evolution of biological forms with fixed laws in the universe.
- Evolutionary theory explains why certain things exist and others do not through selection.
- Assembly Theory (AT) offers an explanation and quantification of the emergence of selection and evolution.
- Complexity is measured using the Assembly Index (a), which represents the minimum number of steps needed to construct an object from basic building blocks.
- The study explores internal structure and properties of assembly space, quantifying undirected exploratory processes and directed processes arising from selection.
- AT enables quantification of how selection emerges in physical systems as they transition from undirected-discovery dynamics to selected processes within assembly space.
- AT provides insights into understanding when and how selection and evolution begin, leading to a formal approach for defining life.
- Assembly Theory allows for easy calculation and measurement of object assembly, providing a lower limit on the amount of selection and memory required for generating complexity associated with biology in our universe.

## Summary

Since the time of Darwin, scientists have been grappling with the challenge of reconciling the evolution of biological forms within a universe governed by fixed laws. These laws establish the foundation for the origin of life, evolution, human culture, and technology as dictated by the boundary conditions of the universe. However, these laws are unable to predict or explain the emergence of these complex phenomena. In contrast, evolutionary theory operates in the opposite direction by elucidating how selection can account for why certain things exist while others do not. To comprehend how open-ended forms can arise in a forward-process from physics without any inherent design, a fresh approach is required to understand the transition from non-biological to biological systems. This paper introduces Assembly Theory (AT), which offers an explanation and quantification of the emergence of selection and evolution. In AT, complexity of an observable object is measured using its Assembly Index (a), which represents the minimum number of steps needed to construct that object from basic building blocks. By combining a with copy number, a new quantity called Assembly is defined to quantify the amount of selection necessary for producing a given ensemble of objects. The study delves into exploring internal structure and properties of assembly space while quantifying both undirected exploratory processes and directed processes arising from selection. The implementation of assembly theory enables quantification at any scale regarding how selection emerges in physical systems as they transition from undirected-discovery dynamics to selected processes within assembly space. This mechanism provides insights into understanding when and how selection and evolution begin ultimately leading to a formal approach for defining life. One significant advantage offered by assembly theory is its ability to easily calculate and measure object assembly; this allows for quantifying a lower limit on amount of selection and memory required to generate complexity uniquely associated with biology in our universe. Overall this research presents Assembly Theory as novel framework that sheds light on how selection and evolution emerge in physical systems; it provides deeper understanding on transition from non-biological to biological systems offering formal approach for defining life.