You always knew that Brahms could be dark, but not as dark as the Piano Quartet No. 3 (Op. 60). Debussy had plenty of artistic descendants - as everybody knows - but who knew they'd be so mutually illuminating when grouped together?

The opening piece, Mozart's Flute Quartet in C major, didn't quite count: It was the program's throat-clearer, a perfectly nice piece in a perfectly fine performance by the Marlboro ensemble headed by the Cleveland Orchestra's principal, Joshua Smith.

More complicated harmonies were on the way with the craftily devised triptych of post-Debussians. Finnish Kaija Saariaho latched onto Debussy's otherworldly mysteries in her 1997 Mirrors; the Japanese Toru Takemitsu reflected Debussy's Japanese-influenced nature studies with a modern Asian accent in his 1996 A Bird Came Down to Walk; while an excerpt from Olivier Messiaen's 1941 Quartet for the End of Time picked up on the distilled rationality of Debussy's late chamber sonatas.

Those who know Saariaho's music weren't the least bit surprised when the flutist whispered enigmatic French aphorisms through his instrument when not playing notes. For the Saariaho-deprived (poor things), Mirrors wasn't asked to make sense amid the implied backdrop of Debussy's French symbolist side - or, in the case of Takemitsu, to leave a Germanic imprint on your brain; his music was like a sweet dream that you can't remember afterward.

The Messiaen movement countered that amorphousness with a steady, simple piano accompaniment over which the violinist (Soovin Kim, not having his best night) went exploring as each phrase headed down a familiar path, then veered into the unknown.

Few pianists begin Brahms' Op. 60 with such an implacable sense of doom as Israeli artist Renana Gutman. The sonority was large and blood-chilling, almost as if she were playing a concerto rather than chamber music, and louder than Arthur Rubinstein or anyone else I've heard in this piece. Where can any musical narrative go from there, when all is lost in the first moment?

The ensuing music shows Brahms at his most substantial, though the discursive qualities of other performances were completely subverted by the ongoing question "What now?" Some performances seize upon any possible moments of repose in the piece; this one had an honest lack of sentimentality.

The smallness of the American Philosophical Society added to the emotional claustrophobia. But the tough-eared Chamber Music Society crowd appreciated such greatness even when served up so bleakly.