"Well, the break-up of the Austro-Hungarian Empire, the whole problem faced by this was probably one of the causes which made me shift my interest from pure natural science to political problems. It meant observing the collapse of the society and more especially, the collapse of the intellectual society of Vienna. The Vienna was, as you said and remained for a number of decades one of the great intellectual centers of the world. Nothing could be more exciting than Vienna of the 1920s and early '30s."