  Various terms for a distinction in this vicinity have been employed. Hermann Siebek (1875, 7) and von Hartmann (1888, vol. 2, 35, 208) both used the term ‘Vehikel’ to refer to the material or perceptible bases of aesthetic objects and works of art. Volkelt (1905, 11) used the term ‘Ausserdinge’ to refer to the non-psychological items that make up what he called the “pre-aesthetic basis of the work of art.” H. S. Goodhart-Rendel (1934) distinguished between the material of art, the artistic vehicle, and the work of art. His idea is that the vehicle is whatever is used to “externalize” the work or to “disclose it to the world” (1934, 4). In the case of music, the sound is the vehicle; sound is not the artist’s material, however, because some musicians can compose in their heads, and on Goodhart-Rendel’s usage, only those media that are necessary to working in an art form are to be taken as materials. All that is strictly necessary to musical composition is an idea or thought of a sequence of sounds.