Thematic and Non-Thematic Textures in Schubert’s Three-Key Expositions

This article reexamines two common views of Schubert’s three-key expositions: one that contends the third key is presented in the context of thematic formal function, another that asserts this section’s function is non-thematic. Considering texture as an important determinant of formal function, these two views are assessed using a computational model of texture. Applying this model to a corpus of two-key expositions from the late eighteenth century, I demonstrate that certain textures tend to be associated with thematic function more than others. This model is then used to determine the presence of thematic and non-thematic textures in three of Schubert’s three-key expositions and the extent to which the two views of the formal function of the third key make sense.