In this clip from The Dark Knight, Heath Ledger describes Joker's motivations. The Joker just does things because he can. This is seen in murderers. Murderers have low impulse control, and when the thought of killing someone pops into their head, they act on it.
The Joker's behavior can also be seen is anticlimactic . He says that he's like a "dog chasing cars." He puts in time, effort, energy, thought into catching the "car," and once he has it, that's that. There is a let down, and Joker then repeats the chase in order to see if he can get a different response. A similar circumstance occurs with children; They tell a joke that they think is funny, when it really is not that funny, and continue to tell the joke until they get someone to laugh.
In this clip, Joker describes his greatest weapon: fear. The Joker takes what the public fears the most and becomes a living manifestation of that fear. After 9/11, everyone was afraid of terrorist attacks, to the point that a large percent of the public "decided to drive instead of fly—believing they were avoiding risk—road deaths rose by more than 1,500" (Gardner 1968). The Joker uses terrorism to bring Gotham city to its knees.
According to Joe Navarro, a terrorist divides the world into that which is useful to him, and that which no longer is. In this scene from the Dark Knight, Joker has five men help him rob the bank, each man has a specific job. One takes care of the alarm systems, one gets the safe open, two for strength, and one for the get away bus. Once each man has served his purpose, the Joker kills them or has one of the other goons kill them. This scene shows the bus driver. Once he has loaded the money into the bus, the Joker does not need him, so the Joker kills him. This behavior mirrors a terrorists division of the world into that which is useful, and then suddenly useless.
Joe Navarro believes that a terrorist has an intractable mind, a mind that is made up, stubbornly resilient, unbending, even when confronted with reality. Joker shows this trait in the previous scenes from The Dark Knight. He is convinced that deep down, the normal people are just as evil as he is. When the people of Gotham City prove him wrong by not blowing up the ferry with the felons onboard, Joker still decides that he will blow them up. His reluctance to give up his beliefs is synonymous with the intractable mind of a terrorist.
One trait of a terrorist is that they “tend to be incomplete human beings” (Navarro). The Joker clearly views himself that way. In this scene, when the banker asks the Joker what he believes in, the Joker replies “I believe whatever doesn’t kill you simply makes you stranger." Joker then shows the banker his scarred face. Joker thinks that whatever incident lead to his facial scars has mad him different from the rest of humanity.
Heath Ledger’s Joker is another adaptation to the modern fears of Americans. His Joker is a terrorist. The definition of a terrorism is “violence when intended for a civilian population to exact their compliance” (Navarro). In the Dark Knight a man named Reese is about to reveal the Batman’s identity, when the Joker calls up and says that he does not want Reese to spoil everything but “why should I have all the fun? Let’s give someone else a chance. If Coleman Reese isn’t dead in sixty minutes, then I blow up a hospital." Joker’s threat fit in with an act of terrorism. Ordinary citizens try to kill Reese, to prevent the Joker from blowing up a hospital that may have their family members in them. Officer Burg tries to kill Reese because his wife is in the hospital. Another example is when the Joker has Harvey Dent’s Girlfriend Rachel abducted. Rachel is abducted by one of Commissioner Gordon’s detectives, Ramirez. When Harvey Dent, now Two Face, confronts Ramirez and asks her why she abducted Rachel, Ramirez says that Joker got to her a while ago, since her mother is in the hospital. Joker used violence to coarse the people of Gotham City into doing his dirty work.