WESTON — “This is a dangerous enterprise,” Malcolm Bilson announced. The pianist was referring to finishing music Franz Schubert left unfinished, but he might have meant the whole process of bringing chronologically old music into the present. Bilson’s recital— opening a Chopin Symposium at the Rivers School Conservatory, but covering a range of composers — percolated with historiographic paradox, the way an incomplete record is both symptomatic of antiquity and an irresistible temptation to fill in with modern conjecture.
Bilson’s restoration project was three incomplete Schubert sonata movements. Two could be wound up according to classical formal tenets; Bilson bound off the threads with agreeable taste. The D. 346 Allegretto, widely assumed to be the finale to the D. 279 C major Sonata, was suitably jaunty and bumptious; while Bilson’s completion of the Allegro of the D. 571 F-sharp minor Sonata slipped in with unassuming logic.