Sonata Theory

Sonata Theory is an approach to the description of sonata form in terms of individual works' treatment of generic expectations. For example, it is normative for the secondary theme of a minor-mode sonata to be in either the key of III or v. If a composer chooses to break this norm in a given piece, that is a deviation that requires analytical and interpretive explanation. The essentials of the theory are presented by its developers, James Hepokoski and Warren Darcy, in the book Elements of Sonata Theory, which won the Society for Music Theory's Wallace Berry Award in 2008.[1] Although the theory is particularly designed to treat late-eighteenth-century works such as those by Mozart, Haydn, and Beethoven, many of its principles are applicable to works in sonata form from later centuries.

Rather than attempt to prescribe a set of rules to which all pieces in sonata form must adhere, sonata theory seeks to demonstrate that sonata form is "a constellation of normative and optional procedures that are flexible in their realization." A work in sonata form is expected to accomplish certain goals; how it goes about this task is to be understood in relation to a set of background stylistic tendencies. The theory, then, understands the sonata as an example of dialogic form: the compositional choices that create an individual piece of music are in dialogue with generic norms and expectations. A large component of the theory is therefore a reconstruction of what these norms were based on an extensive study of the late-eighteenth-century repertoire.

Central to this undertaking are the notions of defaults and deformations. At any point in a sonata movement, such as at the beginning of the secondary theme or the end of the development, a composer had various choices for how to proceed. The most typical option, or the first level default, might be bypassed in favor of a second (or lower level) default. For example, developments most frequently begin by recalling the exposition's primary theme in a new key, but a development might also begin episodically by introducing new material, which Hepokoski and Darcy posit "may be a second-level default option." On the other hand, a composer might choose for this moment of the piece to behave in a genuinely atypical way. This is what Sonata Theory terms a "deformation" of normal practice. The term deformation is not meant to suggest an aesthetic judgment (along the lines of "malformed") but rather is intended as a technical term indicating a significant deviation from ordinary practice. Indeed, deformational moments are often the most unusual, interesting, and pleasing aspects of a work: "Deformations are compositional surprises, engaging forays into the unexpected. But the paradox of art is that the nature of the game at hand also and always includes the idea that we are to expect the unexpected." A central part of the analytic and interpretive work of Sonata Theory lies in recognizing these deformations and default choices and understanding how they affect the progress of a piece as a whole.

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