"imageless thoughts", and the debate between Wundt and the Würzburgers, the "imageless thought controversy". Wundt referred to the Würzburgers' studies as "sham" experiments and criticized them vigorously. Wundt's most significant English student, Edward Bradford Titchener, then working at Cornell, intervened in the dispute, claiming to have conducted extended introspective studies in which he was able to resolve the Würzburgers' imageless thoughts into sensations, feelings, and images. He thus, paradoxically, used a method of which Wundt did not approve in order to affirm Wundt's view of the situation. The imageless thought debate is often said to have been instrumental in undermining the legitimacy of all introspective methods in experimental psychology and, ultimately, in bringing about the behaviorist revolution in American psychology. It was not without its own delayed legacy, however. Herbert A. Simon (1981) cites the work of one Würzburg psychologist in particular, Otto Selz (1881–1943), for having inspired him to develop his famous problem-solving computer algorithms (such as Logic Theorist and General Problem Solver) and his "thinking out loud" method for protocol analysis. In addition, Karl Popper studied psychology under Bühler and Selz in the 1920s, and appears to have brought some of their influence, unattributed, to his philosophy of science. Gestalt psychology Whereas the Würzburgers debated with Wundt mainly on matters of method, another German movement, centered in Berlin, took issue with the widespread assumption that the aim of psychology should be to break consciousness down into putative basic elements. Instead, they argued that the psychological "whole" has priority and that the "parts" are defined by the structure of the whole, rather than vice versa. Thus, the school was named Gestalt, a German term meaning approximately "form" or "configuration". It was led by Max Wertheimer (1880–1943), Wolfgang Köhler (1887–1967), and Kurt Koffka (1886–1941). Wertheimer had been a student of Austrian philosopher, Christian von Ehrenfels (1859–1932), who claimed that in addition to the sensory elements of a perceived object, there is an extra element which, though in some sense derived from the organization of the standard sensory elements, is also to be regarded as being an element in its own right. He called this extra element Gestalt-qualität or "form-quality". For instance, when one hears a melody, one hears the notes plus something in addition to them which binds them together into a tune – the Gestalt-qualität. It is the presence of this Gestalt-qualität which, according to Ehrenfels, allows a tune