Bühler was one of the first to understand the immense theoretical importance of phonology and of the abstractive procedures underlying the grasp of phonemes not just for language theory but also for the theory of knowledge as a whole. In Sprachtheorie Bühler wrote, “The phenomenon of abstraction holds a key position in sematology [Bühler’s term for semiotics] , to which we will have to return time and again” (ST 45). Indeed, “it is a general sematological principle that all things or events in the world which we use as signs are used according to the principle of abstractive relevance” (ST 224) . The key axiom of the sign character of language, based on this principle, not only pointed, as Karl Popper (1963: 293 ff) saw quite clearly, to the impossibility of a purely physical approach to the phenomena of signs and meanings, but also, by extension, furnished a paradigm for constructing a model of human cognitional process, involving the primacy of an intentional set’ in semiosis. In his earliest book-length semiotically oriented work, Die Krise der Psychologie, Bühler insisted on the central idea of “the clearly recognizable and never mistaken duality of phonic image and g word meaning . . . ; this analogy and the complex relation between sign and meaning which is derived from it is ever to be found in the most complex variations in all sense-filled experiences” (KP 14) .