In various areas of modern physics, there is increasing evidence that the foundations of physics need to be revised. New insights come, for example, from quantum gravity, quantum information theory, and modern approaches to quantum many-body systems. For complex systems in statistical physics, condensed matter, and biological systems, new challenges arise at both the conceptual and theoretical levels. New insights are especially needed in cosmology to explain the complex science of the structure and evolution of the universe. In the new CAS Research Focus “Foundations of Physics”, scientists from different areas of physics, together with researchers from the philosophy of science and epistemology, are putting the fundamental physical foundations to the test. | Stephan Hartmann ist Professor für Wissenschaftsphilosophie an der LMU und Direktor des Munich Center for Mathematical Philosophy. |Daniele Oriti leitet eine Heisenberg-Gruppe am Arnold Sommerfeld Center for Theoretical Physics der LMU.