What, exactly, is the audience to make of Evelyn (Rachel Weisz), the hateful yet sexy graduate student who is the focal point of Neil LaBute's The Shape of Things? An imperious art-theory major with come-hither lips, she is first seen in a museum, where she's preparing to deface a marble statue by spray-painting over its fig leaf. This may seem a quaint, not to mention far-fetched, act of bourgeois terrorism (the year, after all, is not 1968), but for sheer implausibility it is trumped when Evelyn agrees to a date with Adam (Paul Rudd), the museum guard, a bespectacled dork of such earnest, grinning wimpitude that it's a stretch to think these two would even carry on a flirtation. During the next several weeks, she treats him like a leashed puppy, and he is so enthralled by her erotic charms that he succumbs to a total identity makeover: new haircut, new physique, new clothes, new nose.
By the time ''The Shape of Things'' reaches its supposedly devastating finale, you'll know why this unlikely hookup is a mathematically precise metaphor for the current disconnect between the sexes. What it isn't is a believable relationship. Yet that may scarcely matter to LaBute, a gifted and corrosive wordsmith who appears intent, by now, on shoving all romantic couplings into the meat grinder of his misanthropic design. There's another miserable campus pair in ''The Shape of Things'' -- Adam's loutish best friend, Philip (Frederick Weller), and Philip's fiancée, Jenny (Gretchen Mol), whom Adam was too shy to ask out himself. LaBute, adapting his 2001 play, entwines the four in some skillfully intense dialogue, and when Gretchen Mol, with her soft-eyed vibrance, is on screen, you flash back to the provocative explorer who lent his characters a sense of mystery in ''In the Company of Men.'' But ''The Shape of Things'' is didactic rather than enigmatic. Neil LaBute has come to declare the death of love, and damned if he'll let any human beings stand in the way of his thesis.