Chapter 4 attempts to critically revise classical Stability, and to resituate its implicit conditions within a broader operational framework that also encompasses dynamic change. In doing so, it foregrounds the role of time – understood through the perspective of Bergson’s notion of Duration – in the occurrence of difference and transformation. The theoretical argument builds up a possibility space predicated on three dimensions (structural permanence, hierarchical orientation and relational composition). As in previous chapters, it then proceeds to explore the sets of conditions that – while being inscribed within this space of possibilities – explicitly distance themselves from the structural limit of classical Stability. This exploration attempts to assemble the notions of Field (as defined by Stan Allen), Event (initially extracted from the writings of Alfred North Whitehead and subsequently revised by Sanford Kwinter) and Alloy (brought in via the studies in crystallography of physicist and art critic Cyril Stanley Smith). The goal of this conceptual exercise is the articulation of an operative framework in which notion of dynamic development in architecture is characterised as being simultaneously continuous and heterogeneous. Hence, this chapter describes the unstable in architecture (or, more precisely, the operations leading to an expanded notion of architectural trans-Stability) as a medium of continuous development over time. Within this scenario, and drawing from the work of Bernard Cache, the role of the architect is reconfigured as a series of operational endeavours entailing actions of both framing and capture.