CANNES — Anyone who even casually follows Woody Allen's career knows that these days the prolific filmmaker delivers just as many misses as he does hits. Last year, Allen directed Emma Stone and Colin Firth in the not-so-enchanting "Magic in the Moonlight." His follow-up, "Irrational Man," premiered today at the 2015 Cannes Film Festival and once more finds Stone front and center as his muse. To say it's better film than "Moonlight" may be a compliment, but we won't pretend it's not a backhanded one.

The story begins at fictional Braylin College in Newport, Rhode Island with the impending arrival of famed philosophy professor Abe Lucas (Joaquin Phoenix). Lucas has a reputation for being something of a womanizer and an alcoholic, but his writings are so inspiring the school's staff and students are in something of a tizzy over his joining the faculty. One of those students is Jill Pollard (Stone), a philosophy major whose overly supportive parents (Ethan Phillips and Betsy Aidem) are tenured in the music department. She soon befriends her new teacher, whom she immediately begins to obsess over, much to the chagrin of her adorable boyfriend (Jamie Blackley).  

Unknown to the fine people at Braylin, however, is that Abe is not in a good place. He has a severe case of writer's block and has basically succumbed to something of an existential crisis. By her own admission, Jill is attracted to men that need mothering and soon finds herself doing the one thing she said she wouldn't do: falling for him. Abe, on the other hand, is already involved sexually with another member of the faculty, Rita Richards (Parker Posey). An unhappily married woman, Rita fantasizes about running off with Abe to Europe and starting her life over again.

As the film unfolds, Abe continues to do everything he can to keep his relationship with Jill platonic. That changes after they eavesdrop on a disheartening conversation between a divorced mother and her friends at a local diner. The woman’s crisis kickstarts a moral debate in Abe's head, which, for better or worse, provides him with some direction in his life and breaks down his aversion to being romantically involved with Jill.

What Abe does next takes the film into darker territory that plays with the philosophical ideas Allen wants to explore. His characters may spout Kant and debate the ethics of different human interactions, but it's only sugar coating on top of what is effectively a simple and familiar story. It doesn't help that the film has a lightness to it that diminishes the consequences of Abe's actions. In theory, "Irrational Man" should feel as though it stands alongside serious Allen dramas such as "Match Point." Instead, it seems more at home next to his other recent efforts, the middling "To Rome With Love" or the whimsical "Midnight in Paris."  

It's also hard to sit through "Irrational Man" and wonder why Allen has written another movie where a May-December romance is the film's main relationship. This is head scratching considering the aforementioned "Moonlight" featured the same construct just a year ago. Young ingenues may be a key part of foreign financing these days, but we find it hard to believe a man of Allen's talent couldn't find another way to present the ethical and philosophical arguments the picture wants to explore.

Stone, it should be noted, does everything she can to bring some realism to the proceedings. The Oscar nominee sells us on Jill's infatuation with Abe even when Phoenix’s disinterest makes it hard to comprehend the attraction. She also finds a way to deliver much of Allen's exposition-filled dialogue with a contemporary energy it sorely needs. Stone is so good and charismatic that in one pivotal scene near the end of the film you begin to forget she’s acting opposite a much more celebrated peer. In theory, she should be the next great Woody Allen muse, but he hasn't given her the material yet to make it a truly memorable collaboration.

As for Phoenix, all of the frenetic energy and charisma from his performance in "Inherent Vice" is long gone here. His portrayal of Abe is so understated it's hard to comprehend why Jill or Rita would fall for him in the first place (or why he’d play him that way). Posey is a unique talent who should have appeared in Allen's films years ago, but she's only given so much to do here. She still finds a way to make Rita more three-dimensional and memorable than the material demands, however.

This is director of photography Darius Khondji’s sixth film with Allen. He shoots it with a golden sheen that casts Stone in a particularly luminescent light and makes good use of Newport’s coastline.

"Irrational Man" opens in limited release on July 17.

With over a decade of experience in the movie industry, Ellwood survived working for two major studios and has written for Variety, MSN and the LA Times. A co-founder of HitFix, Ellwood spends his time relaxing hitting 3’s on the basketball court and following his beloved Clippers.