Metrology of Complexity and Implications for the Study of the Emergence of Life

TL;DR

This paper discusses the development of measurement standards for molecular complexity to better understand life's emergence and improve cross-context comparisons in origin-of-life research, with implications for astrobiology.

Contribution

It introduces a metrology-based framework using molecular assembly theory to quantify complexity and unify diverse experimental approaches in origin-of-life studies.

Findings

Molecular assembly theory enables quantification of molecular complexity.

Standardized complexity metrics can bridge different origin-of-life hypotheses.

Measuring complexity aids in detecting life signatures beyond Earth.

Abstract

One of the longest standing open problems in science is how life arises from non-living matter. If it is possible to measure this transition in the lab, then it might be possible to understand the physical mechanisms by which the emergence of life occurs, which so far have evaded scientific understanding. A significant hurdle is the lack of standards or a framework for cross comparison across different experimental contexts and planetary environments. In this essay, I review current challenges in experimental approaches to origin of life chemistry, focusing on those associated with quantifying experimental selectivity versus de novo generation of molecular complexity, and I highlight new methods using molecular assembly theory to measure molecular complexity. This metrology-centered approach can enable rigorous testing of hypotheses about the cascade of major transitions in molecular order marking the emergence of life, while potentially bridging traditional divides between metabolism-first and genetics-first scenarios. Grounding the study of life's origins in measurable complexity has significant implications for the search for life beyond Earth, suggesting paths toward theory-driven detection of biological complexity in diverse planetary contexts. As the field moves forward, standardized measurements of molecular complexity may help unify currently disparate approaches to understanding how matter transforms to life. Much remains to be done in this exciting frontier.