Abstract
The early twentieth century saw the development of two revolutionary physical theories: relativity (see space, time and relativity) and quantum mechanics. Relativity theory had an immediate impact on the rise of logical positivism, as philosophers like Carnap, Reichenbach, and Schlick struggled to come to terms with its content and implications (see logical positivism). By contrast, discussion of philosophical issues raised by quantum mechanics began among physicists who created the theory before being taken up by technically inclined philosophers of science.