Classical music is alive and well—inspired performances of the standard repertory abound, and brilliant new works are being created. One could almost say that new dimensions of the tradition are being discovered, a resonant string theory to replace Newton’s physics.

Last night at the 92nd Street Y in New York City, the traditional and the new were on resplendent show, with Mozart and Mendelssohn as bookends for Mark O’Connor’s virtuostic, boundary-breaking fiddling. Jaime Laredo, long-time artistic director of chamber music at the Y, brought together nine musicians, masters of collaborative string theory, to make wonderful music.

Laredo joined the Julliard String Quartet—Joel Smirnoff and Ronald Copes, violins; Samuel Rhodes, viola; and Joel Krosnick, cello—in a crisp, emphatic performance of Mozart’s Quintet in C Major, K.515. The violin-cello byplay of the first movement was full of knowing wit, while the second was almost Budapest-lush. By the finale, the performers were so energetic and attuned they were nearly leaping out of their chairs, and afterward much of the audience did the same. The quintet was as precise as an atomic clock, yet suffused with emotion. If this is Newtonian music, it has been brought to a new level of interpretation.

The Mendelssohn Octet in E-flat Major, Opus 20, was performed by the Julliard Quartet with Laredo, Joan Kwuon, and Hiriko Yajima on violins, and cellist Sharon Robinson. It is almost unbelievable that this rich, complex work was written by a 16-year-old; the passages of sonorous, symphonic Romanticism are offset by light, irreverent stretches that are prophetic of his soon-to-come "Midsummer Night’s Dream." The performance was expansive and yet disciplined, joyous in its scope; the occasional slip in coordination was no doubt the result of limited joint rehearsal time.

And then there was O’Connor. Imagine that Niccolò Paganini was born in Nashville: that’s Mark O’Connor. He was a folk fiddle prodigy and won the National Old-Time Fiddler’s Contest four times by age 22, and he is now a skilled classical violinist as well. His fingers fly over the strings as though they were from a planet with a faster time scheme, and yet the music produced is much more than fireworks: he plays with both precision and passion.

His compositions are always charming, sometimes breathtaking. Last night he played, with cellist Robinson, a wonderful set of variations on the folk tune "When Bidden to the Wake or Fair." Then, with Robinson, Laredo, and Smirnoff, he played the first movement of his Quartet, which in the space of a few minutes contains echos of Handel, Bach, an Irish jig, the blues, and Vivaldi, all wrapped in a traditional structure and performed with virtuosity. O’Connor concluded with two Paganiniesque caprices, one of them played on a specially tuned fiddle; they were melodic and broadly conceived, and his performance was brilliant. Throughout the spectacular displays of musicianship, O’Connor conveyed the relaxed, audience-friendly demeanor of a folk musician. As a Los Angeles Times critic said, he has "crossed over so many boundaries,… his style is purely personal."

When music like this is performed—and performances like these are possible—it is time for us all to rejoice. There is hope for the human race after all.