Assembly Theory Provides A Measure of Specified Complexity That Quantifies but does Not Explain Selection and Evolution

Categorizing complex objects into ‘life’ and ‘not-life’ buckets is hard. Understanding how the ‘life’ objects came to be in the first place is even harder. The authors of assembly theory (AT) purport to make headway on both issues by providing a measure, dubbed assembly, for categorizing objects and a related mechanism, dubbed selection, underlying their discovery. We show that assembly is a measure of specified complexity, leveraging the assembly index a_i for the complexity of the object and the copy number n_i for its specification. This provides a theoretical foundation for AT’s success as an object-categorizer. AT’s model for selection yields some helpful parameterizations, but lacks concreteness, and does not grapple with the confounding factors that make the problem of life’s origin so challenging. At best, AT’s selection model highlights the actual problem that a viable selection process must address: the problem of information.