Wertheimer had been a student of Austrian philosopher, Christian von Ehrenfels (1859–1932), a member of the School of Brentano. Von Ehrenfels introduced the concept of "Gestalt" to philosophy and psychology in 1890, before the advent of Gestalt psychology as such. Von Ehrenfels observed that a perceptual experience, such as perceiving a melody or a shape, is more than the sum of its sensory components. He claimed that, in addition to the sensory elements of the perception, there is something extra. Although in some sense derived from the organization of the component sensory elements, this further quality is an element in its own right. He called it "Gestalt-qualität" or "form-quality." For instance, when one hears a melody, one hears the notes plus something in addition to them that binds them together into a tune – the "Gestalt-qualität". It is this "Gestalt-qualität" that, according to von Ehrenfels, allows a tune to be transposed to a new key, using completely different notes, while still retaining its identity. The idea of a "Gestalt-qualität" has roots in theories by David Hume, Johann Wolfgang von Goethe, Immanuel Kant, David Hartley, and Ernst Mach. Both von Ehrenfels and Edmund Husserl seem to have been inspired by Mach's work "Beiträge zur Analyse der Empfindungen" (Contributions to the Analysis of Sensations, 1886), in formulating their very similar concepts of "gestalt" and "figural moment", respectively.