A specter is haunting the sciences - the specter of the thought experiment. Thought experiments promise insights without empirical work, which, for the self-understanding of modern natural sciences, is tantamount to impossibility. Yet, the exploration through thought experiments runs like a red thread through the long tradition in empirical sciences, from their beginnings with Stevin, Galileo, and Newton to the present day. Ulrich Kühne narrates the story of humanity's ancient dream of being able to derive natural laws through pure reason - from the optimism of natural philosophers like Kant and Ørsted to the battles of the "common-sense theorists" with the proponents of abstract natural theories concerning relativity and quantum mechanics. At the heart of the book lies the question of whether, in the rich history of concepts and methods of thought...