Woody Allen’s new movie has Joaquin Phoenix as a rumpled and joyless philosophy professor, spouting Kant and flasking single malt at a lush (but fake) Rhode Island college. His background includes “volunteer work,” “social protest,” and a profound lack of fulfillment, all of which are rather lazily sketched-in. To the local ladies he’s an exotic and romantic creature, or so goes the tired theme on which Allen plays two labored variations. Right away, a lonely fellow prof played by Parker Posey wants to ditch her husband for this guy, and an eager student played by Emma Stone wants to swap him out for her boringly loyal boyfriend. Then things get even more contrived, but also more interesting. An awkward moral-thriller mishmash of Dostoyevsky and Patricia Highsmith, this is one of Allen’s “What can a man get away with?” movies, à la Match Point and Crimes and Misdemeanors, but with a few plot turns just risible enough to make us wish he’d tried it in the style of his own early farces. It helps Allen’s cause that Phoenix these days has such a flair for playing weariness with urgency, and Posey and Stone each redeem near-caricatures with singular emotional credibility. On the soundtrack, the Ramsey Lewis Trio’s piano-driven bop classic “The ‘In’ Crowd” drops in here and there to signify the whirl of mind-gears and turn the screw of suspense. The movie’s most important moment involves a judge, and hinges on a decisively illegal action taken wholly on the basis of hearsay. What an opportunity that is, ethical-consideration-wise, yet Allen just breezes right past it. Adversarial observers of his personal life should note his habit of dramatizing big ideas about culpability not so much by really going to dark places, but instead by suggesting them in lines of throwaway dialogue. Irrational Man is involving, but it feels inadequate.