linguistic:paraphrasing
20th-century theory

Heinrich Schenker argued that there was an Urlinie or basic tonal melody, and a basic bass figuration. He held that when these two were present, there was basic structure, and that the sonata represented this basic structure in a whole work with a process known as interruption.

As a practical matter, Schenker applied his ideas to the editing of the piano sonatas of Beethoven, using original manuscripts and his own theories to "correct" the available sources. The basic procedure was the use of tonal theory to infer meaning from available sources as part of the critical process, even to the extent of completing works left unfinished by their composers. While many of these changes were and are controversial, that procedure has a central role today in music theory, and is an essential part of the theory of sonata structure as taught in most music schools.