This Focus Talk explores the conceptual foundations of physics across an extraordinary range of scales, from controlled quantum systems and precision measurements to the structure and evolution of the universe. The contributions and the discussion will address how quantum mechanics, symmetry principles, and measurements shape our understanding of the world, how experiments test the limits of these ideas, and how cosmological observations challenge established theories. The presentations aim to illuminate where our current picture of nature is solid – and where fundamental insights are still missing.

Moderator: Rainer Blatt