A review of “Pathway Complexity”, a measure claimed to be able to distinguish life from non-life unlike no other measure before

A paper recently published in the Philosophical Transactions of the Royal Society A under the title “A probabilistic framework for identifying biosignatures using Pathway Complexity” claims to offer a revolutionary measure potentially capable of distinguishing life from non-life and even discerning life on other planets by finding biosignatures. The method proposed by its authors consists roughly in finding the generative grammar behind an object and then counting the number of steps needed to generate said object from its compressed form. Unfortunately, this does not amount to a new measure of complexity. The first part of the algorithm is mostly a description of Huffman’s coding algorithm (see ref. below) and represents the way in which most popular lossless compression algorithms are implemented: finding the building blocks that can best compress a string by minimising redundancies, decomposing it into the statistically smallest collection of components that reproduce it without loss of information by traversing the string and finding repetitions.

Source: goo.gl