In International Relations arguments about historical origins provoke theoretical debates, as origins assume an emergent theoretical unit of inquiry - an international order, system, society, etc. - while at the same time defining its core properties and dynamics. By boldly casting the long 19th century as the origin of global modernity and, in turn, the modern international order, Buzan and Lawson's The Global Transformation challenges the romance with Westphalia that undergirds so much of our theorizing. Yet, the contributions to this (...) symposium push deeper than usual, challenging established ways of conceiving change, and suggesting very different models of proper theorizing. While all of the papers ostensibly debate large-scale systems change, three modes of change are in contention: breakpoint, evolutionary, and processual. The further one pushes towards the latter, however, the more elusive the idea of 'system' becomes, eroding the fundamental boundary condition that undergirds the systemic mode of theorizing that dominates the field. Similarly, a persistent theme in these contributions is Buzan and Lawson's purported failure to theorize change. But instead of offering rival theories, contributors advance very different conceptions of theorizing, from pre-observational conceptualization to causal explanation. This not only challenges the field to reflect more systematically on the process of theorizing, but to acknowledge forms of theorizing that it currently brackets. (shrink)