Some common factors which were pointed to include: the shift of focus from vocal music to instrumental music; changes in performance practice, including the loss of the continuo.Crucial to most interpretations of the sonata form is the idea of a tonal center; and, as the Grove Concise Dictionary of Music puts it: "The main form of the group embodying the sonata principle, the most important principle of musical structure from the Classical period to the 20th century: that material first stated in a complementary key be restated in the home key". (The sonata idea has been thoroughly explored by William Newman in his monumental three-volume work Sonata in the Classic Era (A History of the Sonata Idea), begun in the 1950s and published in what has become the standard edition of all three volumes in 1972. 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.
Types
An overview of types 1, 2, and 4 is presented below (type 3 is usually excluded from modern classifications):

Type 1: distal
Distal RTA (dRTA) is the classical form of RTA, being the first described. Distal RTA is characterized by a failure of H+ secretion into lumen of nephron by the alpha intercalated cells of the medullary collecting duct of the distal nephron.This failure of acid secretion may be due to a number of causes, and it leads to an inability to acidify the urine to a pH of less than 5.3. Because renal excretion is the primary means of eliminating H+ from the body, there is consequently a tendency towards acidemia. There is an inability to excrete H+ while K+ cannot be reclaimed by the cell, leading to acidemia (as H+ builds up in the body) and hypokalemia (as K+ cannot be reabsorbed by the alpha cell).This leads to the clinical features of dRTA; In other words, the intercalated cells apical H+/K+ antiporter is non-functional, resulting in proton retention and potassium excretion. Since calcium phosphate stones demonstrate a proclivity for deposition at higher pHs (alkaline), the substance of the kidney develops stones bilaterally; this does not occur in the other RTA types. Normal anion gap metabolic acidosis/acidemia
Hypokalemia, Hypocalcemia, Hyperchloremia
Urinary stone formation (related to alkaline urine, hypercalciuria, and low urinary citrate).