Given the importance that Schoenberg placed on the notion of inspiration, it is ironic that he found this topic so awkward to discuss. He was on other occasions more cogent and less fragmentary than in the sentences quoted above, but his hesitation here serves to remind us that “inspiration” is a concept as vague and difficult to define as it is widely used. Yet it is also a concept as old as the arts to which it supposedly gives birth. Inspiration was to Plato the origin of poetry, and artistic creation itself a kind of divine possession, mysterious and extrarational. In the pre–Enlightenment West, while musical invention was considered to be largely a rational craft that could be learned (an ars inveniendi) along with the basics of harmony and counterpoint, the extrarational element—the “divine spark”—never disappeared from the discourse. In the nineteenth century, the source of inspiration was relocated away from the Deity into the subconscious of the composer (even before the concept of the “subconscious” became current) and was a matter of intense fascination to the romantics. Richard Wagner’s many ponderings on the topic, derived in part from his favorite philosopher, Arthur Schopenhauer, acquired immense significance for the generations that followed him. Particularly influential were his descriptions of inspirational “visions,” such as the opening of his Rheingold, purportedly experienced during a state of half-sleep in La Spezia, and Parsifal, which came upon him, he claimed, one Good Friday morning in Zurich.

From the late nineteenth century onward, prompted in large part by Wagner, the concept of the Einfall was heatedly debated in the German-speaking world. For most composers and commentators (even Hans Pfitzner and Alban Berg, who otherwise seldom agreed on anything), the Einfall signified both the moment of inspiration itself and the motif or melody that is its actual product. As the arch-Wagnerian Thomas Mann once noted, it was “a recent musical category.