Daniels isn’t entirely convincing as a moron, but Carrey was born to lose. He does a wonderfully elastic turn that owes debts to Jerry Lewis’s various descents into idiocy and to the great down escalator that was Steve Martin’s “The Jerk.” Let’s be clear about the level of the humor here: there’s a scene in which Lloyd sets fire to a certain bodily emission. (Rhymes with art.) Still, in its most inspired moments – such as when Harry and Lloyd hit high-society Aspen and spend the cash in the briefcase on orange and powder-blue tuxes – “Dumb” made us convulse with laughter and we’re not going to lie about it now. Carrey is planning sequels to “Ace” and “The Mask,” and surely there’s a movie called “Dumbest” in our future. All that’s a bit much, but Carrey’s role as the Riddler in “Batman Forever” should put some meat on the bones of his career. Meanwhile, “Dumb” is a pleasure in its dopey way. We’ve seen it before, but we’d see it again.