 Criticisms came from Viennese social scientists such as Karl Menger, Edgar Zilsel and Felix Kaufmann. Zilsel, an ally of the Circle, objected to the programmatic nature of Neurath’s foundational work, namely, that it was empiricism without empirical research. They all objected to the narrow strictures on the relation between the natural and the human sciences imposed by physicalism. Kaufmann, in particular, defended a phenomenological sociology, following Husserl much more closely than Carnap especially did, based on the value of introspective experience, although without the scientifically mysterious Weberian method of empathy (Uebel 2007, 255–57).