Previous theories emphasize tonal jazz’s undeniable continuity with European tonality. Here, I argue that some of its features are better understood as developments of the African-American musical tradition. As a simple example, consider the gesture ^3–1 to end a phrase. Schenkerian theory would explain this as an elided ^3–2–1, a gesture common in nineteenth-century music. But the ^3–1 gesture might also be understood as motion within a quasi-modal “ladder of thirds” towards its central pitch.

This paper develops the conceptual aspects of this alternative view. I argue that two phenomena—stable, unresolved dissonances and occasional outright conflict between melody and harmony—are typical of tonal jazz melody and distinguish it from the common practice. I explain these phenomena using two theoretical tools: “ladders of thirds,” structurally coherent stacks of thirds deriving from early African-American music; and Steve Larson’s concept of “contextual stability,” by which dissonant notes can gain structural significance.