Complexity science has generated significant insight regarding the interrelatedness of factors and actors constituting our real world and emergent effects from such interrelationships. But the translation of such rich insight towards developing appropriate tools for improving real world situations of change and uncertainty provides a further significant challenge. Systems thinking in practice is a heuristic framework based upon ideas of boundary critique for guiding the use and development of tools from different traditions in managing complex realities. By reference to five systems approaches, each embodying more than 30 years of experiential use, three interrelated features of the framework are drawn out – contexts of systemic change, practitioners as change agents, and tools as systems constructs that can themselves change through adaptation. The ‘bells that still can ring’ refer to tools associated with the Systems tradition which have demonstrable capacity to change and adapt by continual iteration with changing context of use and different practitioners using them. It is in the practice of using such tools whilst being aware of significant ‘cracks’ associated with traps in managing complex realities that enables systems thinking in practice to evolve. Complexity tools as examples of systems thinking can inadvertently invite traps of reductionism within contexts, dogmatism amongst practitioners, and fetishism of our tools as conceptual constructs associated with ultimately undeliverable promises towards achieving holism and pluralism. The heuristic provides a guiding framework on monitoring the development of tools from different traditions for improving complex realities and avoiding such traps
