Travis frequently changes his view of whether he is in control of his destiny or whether his destiny is predetermined. In the beginning of the film, Travis complains about being lonely and not having any place to go. He tries to control his own fate and change his situation by getting a job and finding a girl. When Travis's plans don't turn out the way he hoped, he shifts the blame away from himself by professing a belief in predestination, claiming he fails because he is meant to be "God's lonely man." By the second half of the movie, Travis has given up on the idea that he has any control over what he does. When he leaves his apartment with the plan of killing Palantine and himself, he notes that this is his destiny and that he never had any choice. Yet he fails in his goal of shooting the candidate, which suggests that Travis's theory about destiny is flawed. Travis creates a new fate for himself by killing Iris's protectors, a decision he makes on his own. Travis, not God, creates this destiny.
Other characters, such as Iris and Wizard, have their own views about how they might change their destinies. Wizard adheres to a more passive philosophy of life, as he tells Travis he'll always be a taxi driver no matter what he does. Travis does indeed remain a taxi driver, which suggests that he may not have as much power over his fate as we might expect. Iris is powerless in many ways, and while her fate may not be predetermined, it is certainly influenced by other people. Sport manipulates and uses her, refusing her the freedom of choice, and Travis forces freedom on her whether she wants it or not. Though Iris came to New York in an act of independence, by the end of the film she has lost control of her destiny.
Among the millions of people in New York City, meaningful personal connections can be few and far between, and in Taxi Driver we see several cases of such urban isolation. Travis resents that the people in his cab pretend he doesn't exist, and in a way, New York itself is an extension of the little world of the taxi: The city is full of people who don't pay attention to each other and who pretend Travis isn't there. Travis isn't the only lonely character in the film. Tom and Betsy flirt with each other, but they don't seem to share a true personal connection. Betsy is lonely enough to consider a date with Travis, a stranger who approaches her from the street. Wizard and the other cabbies congregate at an all-night diner, hinting that they don't have families or stable home lives. The only true relationship in the film is between Sport and Iris, and that relationship is based on illegal exploitation. Taxi Driver contains many shots of crowds, each person going in his or her own direction. To some extent, this view of New York reflects Travis's warped, isolated perspective, but he is not alone in feeling lonely.
Taxi Driver's surprise ending portrays society's glorification of Travis's violence. Instead of dying in the shootout, Travis survives and becomes a local hero, despite having murdered several people in cold blood. The film shows several press clippings hanging on the wall of Travis's room as well as a thankful letter written by Iris's parents. Ironically, Travis, the perpetual social outsider, becomes celebrated in society by violating its laws. The law-abiding Travis was invisible, but the murderous Travis is a hero. In a way, this plot twist validates Travis's criticisms of New York society, which tolerates and even praises violent criminal behavior. Only by acting violently could Travis escape the loneliness that seemed to be his fate.
The windshield of the taxi is the lens through which Travis views the city, and the taxi itself is a vehicle of loneliness and isolation. As the opening credits role, Travis drives his taxi through the city in the rain. The lights of the city are blurred through the rain on the windshield until the wipers reveal the scene. For the second time, the rain blurs the scene through the windshield, but this time the wipers do not make everything clear again. This blurry view suggests that Travis's view of the city and the world is skewed. Travis never sees the world as it actually is. Because his perspective is warped by mental illness, the taxi, in a way, protects him from the outside world. Inside the taxi, Travis isn't vulnerable to jealous men, beautiful women, and his own angry rages. Outside, the world is full of danger. Within the taxi, Travis is safer, but he must endure isolation even when he has passengers. Passengers often pretend Travis doesn't exist, and personal connections are rarely, if ever, attempted.
Though Travis never says anything overtly racist, besides using the word "spook" in his diary, his racism is clear from the way he looks at the black people around him. Travis notices black men everywhere, revealing a deep-seated fear and hatred of black men in particular. The constant shots of groups of black people and black men reveal Travis's obsession. The camera focuses on the black people walking through the streets or sitting in the diner as if they are from outer space. Black people are often shot in slow motion, showing that Travis's gaze lingers on them. He is fascinated with what he hates. Travis's obsession separates him from society, because for the most part the people around Travis accept what goes on. While Wizard and Doughboy are happy to sit around with Charlie T, Travis is uncomfortable. When he leaves the diner with Wizard, Travis looks back at Charlie T, who pretends to shoot Travis with a gun he makes out of his hand. Travis is disturbed by this gesture. Travis also seems jealous of black men. He focuses on the black couple dancing when he watches American Bandstand, as if he is not able to believe that they can be happy while he must be alone.
Only two characters in the film share Travis's racism. The first is the unnamed passenger, who wants to kill his wife for having slept with a "nigger." The passenger gives voice to words Travis thinks but did not have the courage to say, which is why the passenger has so much influence over Travis. Some critics argue that the passenger is an object of Travis's imagination, representing the deepest recesses of his psyche. The other racist character is the man who runs the convenience store. When Travis shoots the young black man who is robbing the convenience store, he worries about the consequences of having used an unlicensed gun. The man behind the counter tells Travis not to worry about it, and he beats the dead man with a crowbar. Travis feels justified in his racism because a few other people share it, even though their feelings probably do not resemble his. In the original screenplay, all the people Travis kills at the end of the film were written as black. Scorsese changed this aspect of the story because he believed racism to that extreme would be too controversial.
Images on television reveal to Travis an alternate reality he himself cannot take part in, where relationships between people are possible. Unlike the actors in the porn films Travis frequents, the people on television seem real to him, and he both envies and resents them. When Travis watches television near the end of the film, he watches it with a gun in his hand, occasionally aiming it at the screen. He watches American Bandstand just after he kills the black man who robs the convenience store. The first image he sees on the screen is a close-up of a young and happy-looking black couple. We get an extended view of the dance floor as the camera zooms into the screen. Amidst all the slow-dancing couples there is one pair of shoes without anyone in them. Travis resembles those shoes not only because he is single, but also because he is not even there. He observes other people's happiness through the lens of television.
Later, Travis watches a soap opera conversation between a husband and wife, which, unlike American Bandstand, was shot specifically for this film. The wife is leaving her husband for her lover. Instead of pointing his gun at the television, Travis tilts the table it rests on until it topples, and the monitor shatters. When the television breaks, so does what's left of Travis's self-control. He has broken his only window onto outside relationships. He puts his head into his hands and rocks back and forth hysterically. At the end of the film, Travis's room post-shoot out contains a new television to replace the old one, indicating that Travis is trying to make a fresh start.
Travis hates the filth of New York City in the summer, and he wishes for a great rain to wash it all away. His definition of filth includes not only the smell of the city or the garbage, but also the people who live in the city, including the black people in Harlem and the prostitutes and hippies in Times Square. In one of his first diary entries, Travis expresses gratitude for a rain that has left the city slightly cleaner than before, but he adds that someday a "real" rain will fall to clean up the city. By this Travis is imagining an apocalyptic flood, one that will separate the people he thinks should be redeemed from those who are not worthy or clean enough. Water takes on the qualities of a redemptive, baptizing force when Travis gives a ride to a prostitute and a john and goes out of his way to drive his cab through an open fire hydrant. He bathes the exterior and interior of his car, both of which have been corrupted by the passengers.
A common lesson for young screenwriters is that a gun that appears in the first scene of a movie must go off before the credits roll. Taxi Driver mocks this axiom by giving its hero, Travis, four guns and a knife. The film is full of guns. Travis views them with a certain reverence, and the first and last shots of the .44 Magnum are slow close-ups panning from the handle to the barrel. Guns take on a powerful significance in Travis's emotional life. He buys his guns only after having been rejected by Betsy, and in a way they help him to be potent after his failure at courting her.
Fake guns have significance as well. Travis and other male characters frequently use hand motions to simulate shooting. The hand has the power to insult and offend, but no power to do any physical harm. Charlie T is the first person to make this hand gesture at Travis, accompanied by a verbal shooting noise, even before Travis buys his guns. Later, Sport makes the same motion when Travis visits Iris. These men mock Travis when they pretend to shoot him, and he is put off by their gestures. After the final shootout, when Travis has no bullets left and the police arrive, Travis puts his hand to his head and pretends to shoot himself. In his maniacal state, he seems to believe this gesture will actually work.
When Travis first encounters Iris, she enters his cab and is pulled out by Sport, who tosses Travis a $20 bill to keep him quiet. Travis takes the money, but he leaves it on the front seat, separate from the rest of his cash. Subsequently, whenever Travis sees the folded bill, he remembers Iris, the filth of the city, and his own silence. For Travis, the bill symbolizes the city's corruption, where anyone can be bought, like a prostitute, for the right price. The money serves as a constant reminder of his own complicity in Iris's situation, and it eventually spurs him to action. He is ashamed that he took the money in the first place, and his shame motivates his later actions. When Travis visits Iris in her room, he uses this bill to pay for his time with her. He returns the money to the man it came from in an attempt to atone for his previous inaction, the first step in his new role as Iris's liberator.