Jim Rutt would describe a phase transition as the process wherein a system undergoes a transformation from one state of matter to another, driven by changes in external conditions such as temperature, pressure, or magnetic fields. This concept is pivotal in understanding complex systems, where the collective behavior of components leads to an emergent change in the system's properties. He would emphasize that, during a phase transition, the system often experiences critical points—moments when small fluctuations can cause large-scale changes, showcasing nonlinear dynamics at play. An example often used is water transitioning from liquid to gas when heated, or from liquid to solid when cooled, illustrating how aggregations of molecules reorganize themselves into distinctly different macroscopic states. This understanding is crucial not just in physical sciences, but also in fields like economics, sociology, and biology, where similar patterns of shifts can be observed.

See also: emergence, evolution, phase change, prigogine, self-organization