The Joker's words forward an ageless idea, that good and evil--here manifest as a devotion to order and a celebration of anarchy--are equal opposites. Taken to its extreme, such moral dualism suggests that the most malevolent action is motivated by purely evil intent, and that goodness simply replicates itself.

At first glance, the villain of Christopher Nolan's The Dark Knight (2008) seems to be what he claims, someone committed to chaos for chaos' sake. He has no apparent friends, family, or loved ones for whose sake he commits his acts of theft and destruction, and even his coworkers in crime regularly receive a bullet to the head or some much more horrible end for their efforts. He kills government figures, destroys hospitals, and even burns mountains of money in his possession for no other reason than to shake the sociopolitical foundations of Gotham. And, to further bewilder those individuals horrified by his strange appearance and stranger actions, he spins numerous, mutually exclusive origin stories to explain the scars on his face and the flashing knives in his hands.

Batman's selfless, self-sacrificing actions throughout the film (particularly at its close), neatly foil his foe's actions, completing the Joker's proposed portrait of two discrete, dueling forces locked in endless struggle.

There is, however, the small but significant matter of the Joker's infamous laugh, an ingredient which ruins his own recipe. If the Joker were truly the polar opposite of our brooding hero, he would take no delight in his own actions . . .

It's not enough for the Joker to be an enigma with incomprehensible impulses, someone whose drive towards chaos is the antithesis of Batman's desire to protect and preserve. The Joker's laughter signals his familiarity with what is a God-given, intrinsic good--delight. That he and Batman each derive pleasure from dramatically different courses of action does not erase the fact that this same principle motivates them. As C. S. Lewis explains in Mere Christianity (1943, 1945), "badness is only spoiled goodness," "a parasite, not an original thing." Evil may possess its own distinct modus operandi, but it lacks a set of motivators to set those actions in motion, and must borrow and bastardize those created by a righteous God. People sin, in other words, to gain what is inherently good, they just pursue that good at the wrong time, to the wrong degree, or for the wrong reason. Sexual arousal, comradery, happiness, emotional security, and any number of other enjoyable experiences in this life only become immoral when pursued at the cost of relationship with the Lord and with others.

Last year's No Country for Old Men introduced us to a cold killer so emotionally detached from his actions and those around him that he came across more as a force of Nature (in the Tennysonian, "red in tooth and claw" sense) than an actual human. By contrast, the Joker's delirious delight in destruction makes him less a riddle than he wishes to be, opening a crack in that mad mask he hopes will repel others' thoughtful gaze. Knowing that he can laugh suggests he has a heart that can be made glad and, perhaps, sad.

This most recent iteration of Batman's greatest foe may not be very sympathetic, but the glee implicit in the psychopath's smile suggests that he might just be human after all.