This chapter explores the dynamics of non-linear changes within social systems, focusing on the processes that lead to societal collapse and ‘emergence’ (when a new social order forms that is qualitatively different from the past). The chapter first reviews the forces that create stability, differentiation, and oscillation. The DIME model is introduced, which explores how activists choose tactics to follow up the success or failure of their collective action. The chapter explores dynamics of intergroup contestation, including polarisation and backlash that drive systems towards either emergence or collapse. System stability is supported through coordinated identities and norm sequences that are often localised spatially, which act as homeostatic mechanisms to create resilient systems. However, behavioural changes manifest as actors establishing new cues and framing collective actions in ways that channel energy towards new identities and norms. Finally, the chapter explores mutual radicalisation, where mutual feedback loops of failure and threat signals between groups drive radicalisation, reinforcing intergroup tensions.