I know all too little about long wave theory to be able to critique these thinkers, but am intrigued by the concepts. The big challenge seems to be identifying processes – from fundamental anthropology, psychology and ecological economics – that can plausibly generate the waves/rhythms. Here are three possibilities – not mutually exclusive at all – that come to mind as ideas to explore. First, J Tainter’s theory of civilisational collapse as a gradual result of diminishing returns from complexity. Second, M Olson’s theory of dysfunction in collective action as a result of accumulating institutional and personal vested interest. ( Both of these build on a principle I think worth elaborating, namely that ‘nothing fails like success’ in the long run, as institutions and individuals hold to patterns of production, consumption and investment that have been successful, even as the world around them evolves in ways that will make them ever less effective.) Third, warfare plays a role in several ways: destruction of vested interests and ‘blocking institutions’; destruction of capital and opening up of spaces for innovation; motivation for rapid change to improve conditions after destruction; mobility within and between societies. None of which makes the case for war; but it does point to ‘what it’s good for’.