You know how Al Pacino has for years seemed like an unfortunate parody of himself? No dummy, Pacino apparently recognizes this, and unsteadily channels his recognition into The Humbling. Arguably the same could be said for Philip Roth, whose 2009 novel is the source of director Barry Levinson’s film, in which Pacino plays an over-the-hill actor having delusions and an affair with his lesbian goddaughter. She’s played by Greta Gerwig, in such a way that it’s never clear whether to feel sorry for her or grateful. “I have been thinking about you inappropriately since it was really inappropriate,” she tells him at one point, but also asks, “So what happened with your acting?” The reasonableness of that question notwithstanding, their chemistry just seems bogus, and anyway, who really wants to see another dated Rothian tightrope walk between male virility and virulence? It’s a mopey, silly situation, whose only tension comes from our perpetual fear that Levinson is about to make us watch a somber drama copulating with a farce. The adaptation was co-scripted by Buck Henry and Michal Zebede — he famously the writer of The Graduate, way back in the presumptive halcyon days of edgy age-inappropriate romance; she whose previous credit is the TV show Devious Maids. Subplots waste willing supporting actors including Dianne Wiest, Nina Arianda, Charles Grodin, and Dylan Baker (though it’s to Baker’s great credit that as the Pacino character’s shrink, seen entirely on Skype, he doesn’t seize a perfect excuse to phone it in). But then, the main plot wastes the main actors too.