For just this one week, American Ballet Theater is presenting itself as modern, up to date, adventurous — if not by all standards, then by those of most ballet companies. Returning for the first time in three years to New York City Center, newly renovated, it’s dancing a different assortment of four or five works in each program, totaling nine in all. Seven of these are by four famous American choreographers from nonballet backgrounds — Merce Cunningham, Paul Taylor, Twyla Tharp and Martha Clarke — and five of them do not involve pointwork. Only some of Ballet Theater’s usual stars are involved; a good many of the company’s soloist and corps dancers are being given individual opportunities. The season avoids the standard ballet clichés of familiar stories and displays of conventionally bravura technique. The emphasis is on freshness and contemporaneity.Since Ballet Theater’s eight-week spring seasons at the Metropolitan Opera House court those same clichés, its brief fall seasons disclose that the company has a divided soul. I don’t suppose any resolution will soon be found — these are problems for ballet itself, though nowhere more than with this company. But on Tuesday’s opening night it was certainly a welcome relief to observe that Ballet Theater had started at last to improve its gala technique. Introductory speeches and thank yous from the stage by the executive director, Rachel S. Moore, and the artistic director, Kevin McKenzie, were warm and well paced. In the four works that followed — which included the world premiere of a piece by the emerging choreographer Demis Volpi — the atmosphere stayed bright, with the dancers projecting surely. On such occasions it’s not unreasonable to feel that Ballet Theater and its audience are a family. Although to greater or lesser degrees I resisted all of the evening’s four works, I could resist few of the dancers.“The Garden of Villandry” (1979), however, does no credit to its choreographer Martha Clarke’s reputation for experimental dance theater. Two men and a woman in late-Victorian attire dance out a ménage à trois while Schubert’s Piano Trio No. 1 in B flat is played at the side of the stage. The general look is so similar to the “Nimrod” section of Frederick Ashton’s “Enigma Variations” (1968) — clothing, specific groupings, even one of the men wearing spectacles — as to seem determinedly derivative. Though “Villandry” goes on to suggest erotic complicity, it meanders and never acquires depth as drama or poetry.“Private Light,” the new ballet by Mr. Volpi, a corps dancer with the Stuttgart Ballet, also features music performed onstage — a peculiar anthology of pieces arranged and played on three successive guitars by Christian Kiss, very beautifully. But Mr. Volpi’s choreography shows little concern for the way his score ranges from a classical-Spanish number by Isaac Albéniz (“Leyenda”) to folk-American ones by Pat Donohue (“Mudslide” and “Novocaine”).His piece is a series of études; and on this evidence — he is only 25 years old — his style veers between the cutely sophomoric and the conscientious apprentice. The lighting, by Bonnie Beecher, is often almost entirely overhead, suggesting that the dancers are in private zones: in some sections it’s hard to see whether the women are on point. The dancers wear shorts, the men are bare-chested.The work begins and ends with male-female canoodling. Five male-female pairs are locked in kisses for whole sections of the work (the women do this on point), though in a brief central scene people regroup so that two women can kiss each other (on point, of course). The overall mood suggests that women live only for love (or at least snogging) but that a guy certainly needs a break now and then. When Simone Messmer has a solo, she’s fraught, apparently because her partner, Cory Stearns, is absent; but when Joseph Gorak has a solo, all that’s on his mind is the chance to point his toes and earnestly deliver a few ballet steps with exaggerated emphasis. Meanwhile, the lighting builds this up into an existential declaration, and his colleagues keep advancing alarmingly on him as if he were pursuing some forbidden activity.In one early section (dismayingly close to a famous scene from Jerome Robbins’s classic comedy “The Concert”) a man carts women around and repeatedly repositions them. Elsewhere an objectionable lift recurs in which men pick up women by the neck. The women do not protest, since this usually leads to more kissing, ostensibly the chief goal of their existence. In expressive, musical, and formal terms, “Private Light” is foolish and trite.Thanks to Twyla Tharp, the evening’s two other pieces — the male-female duet “Sinatra Suite” (1983) and the group work “In the Upper Room” (1986) — gave us choreography of serious and absorbing accomplishment. The wonderful Herman Cornejo can’t consistently banish the shade of Mikhail Baryshnikov, the male role’s creator, but in “Sinatra Suite” he has many moments when, remarkably, his most pure dance steps and positions turn into images of sheer drama, elegance and charm. Though he’s improving as a partner — Luciana Paris was well teamed with him — this still seems to be the area least congenial to his gifts.“Upper Room” is a smash hit now celebrating its 25th anniversary. So why can’t I surrender to it? Philip Glass’s taped music is manipulative to the extreme, climbing in the finale to that worst Hollywood-soundtrack shtick, a chorale of heavenly voices; and Ms. Tharp’s vocabulary is relentlessly big and forceful. Yet even as I reject it, I can’t deny that this was by far the most substantial work on Tuesday’s program, and fascinating in its divided-loyalty crossover style. (Terpsichore is in sneakers and point shoes, shimmying and jogging as well as doing arabesques and pirouettes.)Though Ballet Theater has performed it better in the past, the gist of Ms. Tharp’s concept comes across; and it’s in “Upper Room” that we most feel the pleasure of being back with Ballet Theater. It’s especially good to watch the valiant Sascha Radetsky, the quietly exuberant Isabella Boylston and — best of all because fullest in the quality of his movement — Arron Scott. These dancers make us feel that a one-week season is way too short.