THE SONATA SEMINAR.(pianist Leon Fleisher at Carnegie Hall)

"There are so few notes," the pianist Leon Fleisher said, "but so many implications." The setting was a recent master class at Carnegie Hall. Fleisher, the master in question, was leading four young musicians through the mystical landscapes of the late sonatas of Schubert. He was speaking about the Andante movement of Schubert's B-Flat-Major Sonata, but he might as well have been describing Bach's "Well-Tempered Clavier," or Brahms's Intermezzos, or any other music in which a smattering of notes conveys a world of feeling. "There are so few notes, but the implications go back billions of years," Fleisher went on. "You have to be like the Hubble Space Telescope, which sees ...