Moritz Schlick’s interpretation of the causality principle is based on his understanding of quantum mechanics and on his conviction that quantum mechanics strongly supports an empiricist reading of causation in his sense. The present chapter compares the empiricist position held by Schlick with Bas van Fraassen’s more recent conception of constructive empiricism. It is pointed out that the development of philosophy of science from Schlick’s understanding of logical empiricism to constructive empiricism reflects a difference between the understanding of quantum mechanics endorsed by Schlick and the understanding that had been established by the time of van Fraassen’s writing.