Like most people in this community I suspect, I first encounter Ross Ashby’s ‘Law of Requisite variety’ through Stafford Beer, who regarded it as the foundational concept upon which his cybernetic work was built. As a result, one of the first books I read when I started my PhD was Ashby’s ‘Introduction to Cybernetics’. Subsequently, whenever I have given presentations on my own work, I have always avoided explaining its significance since I assumed that my audience was as familiar with this as me: and I didn’t want to patronise them or embarrass myself. Over the years I have, however, come to the view that I was wrong. If they were aware at all most people have got beyond the aphorism ‘only variety absorbs variety’ which, as it turns out, is misleading at best. In this talk I will explore the significance, limitations and implications of Ashby’s Law through the lens of my personal journey. Along the way I will explain the importance of qua specification, debate whether it is a ‘law’ at all, and explore the relationship between cybernetics and complexity science.