Reality vs. Perception
This film is a landmark of German Expressionist cinema. As such, much of the action is depicted less as a literal event and more as a dreamlike rendering of the characters' perceptions and emotional states. The distinctly unrealistic set design and makeup contribute to creating a filmic world that is based more in a perception of reality than reality itself. Francis is telling the story of the film, and his depiction of events is often uncanny, macabre, and exaggerated. In this way, the viewer is observing his subjectivity rather than a faithful of realistic account. This contributes to our understanding of the general theme about perception versus reality as it is reflected in the plot. Perceptions are consistently being unraveled and reversed throughout the film, and by the end we realize that perhaps Francis was an unreliable narrator all along. When we realize that he is actually a patient at the asylum, and is suffering from delusions, we realize that the entire "reality" of the film has been grounded in a misrepresentation. Thus, we see that a major theme of the film is the fact that that which is "real" depends entirely on perception.
Authoritarianism
Dr. Caligari is a stand-in for an authoritarian leader. In the beginning, his relation to Cesare is that of a master to a slave; he has complete control over Cesare's actions and uses Cesare's status as a somnambulist to commit secondhand murders. Then later, he is presented as an oppressive figure in charge of the mental asylum who is to be feared because of his power and nefarious aims. Later, Caligari is revealed to have gone insane as a result of his obsessive lust for power. Finally, he is revealed to be a benevolent authoritarian figure in charge of the asylum, in the final scene. These various guises all lead to the same question: which is the real Caligari, and if he can be each of these things, then can his authority ever be trusted? Many critics have cited the film as representing the psychological experience of living under an authoritarian government, and exploring the question of power's corruptive forces. Can any authority be trusted, or is power by nature just one step away from lunacy?
Ideological Brainwashing
The original screenplay did not feature the twist ending, and Caligari was a genuine figure of menace who was successfully manipulating the population into a frenzy of fear through the power of suggestion. Caligari needed only to hypnotize Cesare into becoming a killer in order to spread suspicion and paranoia among the citizens. The murders led the citizens of the town to lose trust in their neighbors and seek out the protection of an oppressive authority figure. Even with the twist ending of the final screenplay, the theme of a powerful villain's ability to affect and change people's perception persists. If we look at the film in historical context— 1920s Germany—it reads as a kind of warning to German audiences about the potential danger of a small but rising Germany nationalist ideological movement and the rise of Nazism.
The Madness of Storytellers
One of the implicit themes of the film is its suggestion that storytellers are by definition somewhat mad. The story told in the movie turns out to be the insane ramblings of a mental patient. The movie itself is directed in unusual and Expressionistic strokes, by filmmakers who portray architecture and geometry in warped and unrealistic ways. Every aspect of the narrative invites the audience to distrust its reliability. The film seeks to undermine the audience's trust and faith in storytelling, whether that story is the one told by a mental patient or the director himself. In this way, the film suggests, storytelling is subjective and prone to lapses of objectivity.
Prophecy
When Alan and Francis go to the fair, they wander excitedly into Dr. Caligari's tent. Caligari makes a huge spectacle of revealing his pet, Cesare, before informing the audience that one of Cesare's talents is his ability to tell the future. This ability is at once an exciting gift as well as a forbidding promise. If we know too much about the future, how does that affect our lives and actions in the present? How does the prophecy affect the course of life itself? When Alan eagerly asks Cesare when he will die, Cesare tells him that he will die that evening. Indeed, the prophecy later comes true, when Cesare kills Alan himself. Cesare's prophecy comes true precisely because he makes sure it comes true. In this way, the film blurs the lines of identity between the prophet and the murderer, the seer and the tyrant.
Sleep and Dreaming
Cesare is defined by his status as a somnambulist, a sleepwalker. As Caligari tells the crowd at the fair, Cesare has been asleep for over 20 years. This is a marvel in and of itself, but it also distorts Cesare's accountability. In his constant state of sleepwalking, the somnambulist cannot be held accountable for his actions. For this precise reason, Caligari has him carry out a series of disorienting murders in the town. No one suspects the sleepwalker, precisely because he is always asleep. In a dream-like trance, how could anyone commit murder? Thus, a theme of the film is the notion that in sleep, we are in a kind of moral limbo, not held accountable for our actions. This lack of accountability mirrors the fact that insane people are not held accountable for their actions, and must be subdued rather than brought to justice. Additionally, the film's design and aesthetics can be interpreted not only as reflective of the waking psychological states of the characters, but also expressive of a dream state, in which boundaries are dissolved and nothing is quite as it seems.
Identity
The biggest twist in the film, which comes at the end, is the audience's realization that Francis has misrepresented himself. While we have taken him at his word throughout the film—indeed, he is our way in to the story itself—by the end of the film we realize that he is a patient at the insane asylum, and that his account is unreliable. In this way, his entire identity shifts, as we see that he is really a madman rather than a reliable protagonist. Indeed, all of the characters' identities shift in this final scene: we see that Jane is in fact an insane woman who thinks she is a queen, Cesare is a gentle (and awake) man looking at a flower, and Caligari is their doctor. This shift is disorienting to the viewer, and shows us the ways that identity is malleable.
Additionally, Caligari's identity changes throughout Francis' account. First, he is a mysterious carnival man, then he is revealed to be the asylum director. As asylum director, we learn, he has been obsessed with a historical figure, the actual Caligari, who committed a number of secondhand murders in Northern Italy in the 1700s with the help of a somnambulist named Cesare. This revelation of Caligari's meticulous emulation of history is shocking because it has the effect of collapsing time and calling into question the nature of reality and identity. Who is the real Caligari? Who is the real Cesare? By emulating the actions and taking on the name of a historical figure, does Dr. Caligari actually become that figure? Caligari's appropriation of identity disorients the notion of identity itself.
