How much hand-holding does an audience today want or need? It depends on the audience. When Friday night's Philadelphia Chamber Music Society listeners were told that one of next season's concerts features Schubert's last three piano sonatas, and they oohed and aahed, you knew this was a knowing crowd.

So did Jeremy Denk. His recital  Friday night at the Perelman Theater was a feat of explanatory concertizing. The pianist arranged an evening of two dozen short pieces spanning roughly 6½ centuries. He didn't talk through the recital. After a brief statement explaining that he aimed to capture, at least to some degree, the progress - and then destruction - of tonality, he let the audience's ears do the thinking. It was as if we were back in Dr. Barr's mandatory freshman Survey of Western Music (or whomever you happened to have) – but better.

Of course, there's no set map to such a journey. Denk speaks and writes well about music, but he is a performer first, and you have to assume he chose the landmarks he did because he had something urgent to say. Often he did, especially in the earliest pieces, works of Ockeghem and Purcell, which he treated with moving expressive touches.

Mozart was the calm eye of the storm. By placing the nearly tension-free "Andante" from the Piano Sonata in C Major, K. 545 at the start of the second half of the concert, Denk seemed to be saying the rules of traditional harmony had reached peace. But struggle fanned out from there to works as early as the 14th century, when the rules familiar to us now had not been set, to the 20th and 21st, when every good boy did fine only by breaking the rules.

It was fascinating to hear Denk struggle himself at times. He played nearly the entire recital from memory, and a sense of liberation flowed, especially in the fury of the opening movement of Beethoven's Piano Sonata in C Minor, Op. 10, No. 1.

Ideas bled from one piece to the next, suggesting unlikely connections. Wagner and Brahms became friends. No sooner were you questioning whether Debussy influenced jazz in the "Reflets dans l'eau" from Images, Book I, than Denk was answering in the inverse with Stravinsky's Piano Rag Music.
He sustained the end of Doulz amis, oy mon compleint, by the 14th century Guillaume de Machaut, to meld with the start of Gilles Binchois' Triste plaisir.

Various early works were surprisingly promiscuous with harmonic matters, which that meant by the time you got to Bach's Chromatic Fantasia and Fugue in D Minor, BWV 903, you understood the source of Bach's genius: He codified the rules simultaneously with breaking them. Greater magic never appeared, in music or any other realm.