“An absence of disqualifiers is a rare and beautiful thing,” says the stoic and gentle philosophy professor Harry Stevenson (Morgan Freeman) who occupies the center of “Feast of Love.” Director Robert Benton’s new film itself deserves the same pragmatic and genuine, if not wildly effusive, praise. A narrative expedition that tracks a group of couples struggling to get and stay together, “Feast of Love” bears a circumstantial similarity to big-canvas social dramas like “Magnolia” and “Crash.” But Mr. Benton’s film, based on Charles Baxter’s well-regarded novel, possesses few of those previous films’ strident excesses and self-indulgent contrivances. Instead of fatefully and noisily uniting a disparate group of people through calamity and coincidence, “Feast of Love” diagrams and defines a Portland, Ore., community two people at a time as they are drawn together or driven apart by desire.