Ross Ashby's information theory: a bit of history, some solutions to problems, and what we face today

This paper presents a personal history of one strand of W. Ross Ashby's many ideas: using information theory to analyse complex systems empirically. It starts with where I entered the evolution of the idea as one of his students, points out a problem that emerged as a consequence of generalising information measures from simple to complex systems, i.e. systems with many variables, shows how this problem was eventually solved, and ends with how his idea of decomposing complex systems into smaller interactions reappears in one of the most complex technologies of our time: cyberspace. While nobody could anticipate the complexities that developed since, Ashby's idea of understanding complex systems in terms of manageable interactions, which I call electronic artefacts, is actually practised today and cyberspace is again worth analysing in information theoretical terms.