Abstract
<jats:title>Abstract</jats:title> <jats:p>Open Systems: Physics, Metaphysics, and Methodology argues that many of the most illuminating questions in contemporary science are best approached by treating systems as inherently embedded in, and interacting with, their environments. While closed-system modelling has long dominated physics, recent advances—from non-equilibrium thermodynamics and open-system quantum dynamics to complex systems science and quantum causal modelling—show that environmental coupling is often not a dispensable complication but a defining feature. Bringing together leading scholars across physics and philosophy, this volume develops the “open systems view” and probes its limits. Part I sets out the view within quantum theory and clarifies its relations to alternative frameworks. Part II traces open/closed concepts across the history and practice of physics, from Newtonian celestial mechanics to blackbody radiation, gravity with boundaries, and biological emergence. Part III turns to the largest scales, examining cosmology, many worlds, and realism about the universal quantum state. Throughout, contributors connect formal tools—density matrices, Lindblad dynamics, interventionist causation—with methodological and metaphysical stakes, including autonomy, reduction, and fundamentality. The result is a unified guide to modelling, explanation, and ontology when closure is an idealisation rather than a premise.</jats:p>