The Boston Symphony Orchestra’s latest entries under James Levine in its Schumann and Harbison cycles presented each composer’s second symphony on December 2; as it happened, each in different ways explored some dark corners in their respective worlds. As warm-up, however, the BSO offered some sunshine and grace in the form of Mozart’s youthful Violin Concerto in G major with the young Danish soloist Nikolaj Znaider.

The Mozart was the opener, an unusual bit of programming for a concerto that nevertheless worked aesthetically. By its Köchel catalogue number, 216, one can immediately see that this is a relatively youthful, though certainly not juvenile, work. In fact, all five of Mozart’s violin concerti date from his late teens — this one from 1775 — so despite its completely assured compositional technique, it lacks the phenomenal emotional depth of his mature work. It is also a stylistic hybrid, rather like Haydn’s concerti of the 1760s and 1770s, still showing elements of Rococo and even earlier styles. However, Mozart being Mozart, it never lacks interest, warmth — especially in the slow movement, and wit — notably in its winkingly abrupt and soft ending. For the occasion, Levine brought in one of the hotter tickets on the international virtuoso scene, Nikolaj Znaider, who performed with the BSO last year under Colin Davis. Znaider is tall, handsome, with longish curly hair and an outgoing, ingratiating manner and snappy concert attire that obviously engaged the full hall, especially the troupe of young people in the second balcony who were in a volubly approving mood throughout the program (altogether a good thing, IOHO).

Znaider’s sound is sweet and pure, a little bit demure, very middle-of-the-road in texture. He is also very much a physically communicative performer, moving about and emoting whether he was playing or not. Nothing in the program notes indicated the source of his cadenzas (there was one in every movement), but they, along with Levine’s empathetic conducting and the sprightly and idiomatic playing of the BSO’s reduced forces, were spry, graceful and to the point.

About seven months ago we heard a performance of John Harbison’s Symphony No. 2 (1986), by the New England Philharmonic under Richard Pittman. On that occasion, Harbison mentioned to us that this was his least performed symphony, which, the quality of its construction being of no lesser rank than any of his others (Harbison, of course, didn’t say that, but we’ll vouch for it), he attributed to its somewhat down-at-the-corners spirit and quiet ending. We were reasonably happy with the NE Phil’s performance, but having the work performed by the BSO, whose conductor and players, made up this week to a larger degree than seems usual with substitutes drawn from Boston’s amazingly deep bench of top-notch freelancers, were very much on top of every note and nuance. This allowed one to take a fresh view of the piece, not only in context with the other Harbison symphonies the BSO has done this year, but in its own right. We also wonder if Harbison’s statistics won’t need updating after four performances of this work within a year. It should by rights have been five, but this BSO series, like the one last week that gave Harbison’s First Symphony, was truncated by one: no Thursday last time because of Thanksgiving, and no Tuesday this time to make way for Holiday Pops.

On second hearing, then, we can say that despite inhabiting a sonic world of greater stridency than the First or Third, performed by the BSO in October, and notwithstanding the quasi-programmatic premise of a tour through the successive times of a day (the movements played without pause being headed “Dawn,” “Daylight,” “Dusk” and “Dark”) it is a work of immense interest and power. It is also a tour de force of orchestration, of which Harbison is a supreme master. From the snarling brasses and sawing strings of the second movement to the fluttering winds and massed percussion of the finale, to the astonishing clarity of texture in the first movement drawn from the full resources of a large orchestra, this symphony is a feast for the ears, which the BSO players served up to four-star standards. As suggested above, it is hard to imagine this work getting a better performance than Levine and the BSO gave it Thursday night, so if you can get to its one remaining performance Saturday, or can tune in on the radio, it’s well worth the effort.

Another second symphony that stands in a somewhat pivotal position in its composer’s oeuvre is the C major symphony of Schumann, op. 61. Schumann claimed that it represented something of a long night of the soul; the program annotation by the late John Daverio questioned this assessment. Schumann also regarded this work as a breakthrough in his compositional style, in which he applied lessons learned from sources as diverse as Bachian counterpoint and the structural integration of Schubert’s Ninth Symphony to create a new way of conceiving large multi-movement works. There is no question that Schumann broke new ground in integrating the four movements: a motto phrase of a rising fifth that recurs in every movement, and themes from earlier movements, especially the Andante, are recalled and integrated into the finale.

There are other striking unities as well, unlike standard symphonic practice: every movement has the same C tonic (the slow movement is cast in C minor). However, and perhaps to Schumann’s point about the emotionally troubled quality of the work up to the grand peroration that crowns the finale and carries it home, the harmonic structure within the movements is one of extreme restlessness. The clear C-G phrase of the opening is undercut by the strings’ chromatically shifting countermelody, for example, and the second subject barely touches on the “proper” G major before flitting about into remote keys. The main subject of the scherzo, which in duple meter and with two trios is really more of a rondo, is a quicksilver passage structured around a tonally ambiguous diminished arpeggio. Also, the main theme of the slow movement has moved from C minor to E-flat major by the time its first eight-bar period has ended. Thus, it’s a considerable relief in the finale — whose opening flourish is a C major scale that immediately resolves into G major, here we go again! — when after a big dominant seventh followed by a grand pause, a cheerful tune in chorale-like rhythm that popped up during the development — hey, where’d that come from? — takes its unambiguous C major and runs with it to a rousing conclusion.

Whether you think all this contradiction sits this symphony squarely between two stools or, like David Hoose in his note to last year’s performance by the BU Symphony, you think it makes of it the greatest symphony ever, Levine seized it in all its contradictions and from a deceptively calm and measured opening to its spirited close, gave it as full-blooded a reading as we can remember. He made the most of Schumann’s hairpin dynamic turns on individual notes and punctuated key phrase endings with sudden rubati. Transitional passages were especially well modulated, as from the scherzo’s trios back to the greased lightning of the main theme. Tempi were generally brisk, but only in the slow movement did we find the pace sometimes slightly rushed, pitting the Andante against the espressivo. Our observation was that Levine and the players are on the same wavelength, and digging it immensely. Us too.