Luke Defeats Himself through His Own Egotism
Luke's encounters with Yoda in the Dagobah system initiate the Jedi training process. Yoda first tells Luke that he lacks the youth, patience, and idealism necessary to focus. Luke's father, Anakin Skywalker, failed as a Jedi for similar reasons: anger, egotism, and disillusionment with the Jedi ideals in times of conflict. As viewers of The Empire Strikes Back learn towards the end of the movie, Anakin evolved into the sinister Darth Vader. Luke's attitudes lead to his bad experiences on Dagobah and his sobering defeat at Cloud City when he departs in an attempt at heroism. Ultimately, Yoda foresees Luke's temporary failure, leading to Luke's return to the Jedi training process for Return of the Jedi.
One key element in Luke's defeat in this movie is his consistent failure to "unlearn what you have learned" as Yoda urged. Luke claims to be "looking for a great warrior," to which Yoda replies "Wars not make one great!" When Luke loses all faith in the possibility of utilizing the Force (see the page relating the film to Eastern philosophy) to levitate his crashed X-Wing out of a swamp, Yoda tells him "do or do not; there is no try." Yoda lifts the craft out with the Force alone , to which Luke replies "I don't believe it." In a summary of Yoda's disappointment with Luke's egotistical hindrances to his own attitude, the Jedi Master replies "That is why you fail."
The cave provides enormous symbolism of Luke's defeat by his own ego. To quote Joseph Campbell, "those who set out to slay others will slay themselves." Luke ignores Yoda's premonition that the cave teems with bad vibes (in Star Wars terms, the "Dark Side of the Force"). In the cave, he hallucinates that he fights and decapitates his nemesis, Darth Vader, in a light saber duel. In a chilling and foreshadowing display of the risks of an egotistic quest, Vader's helmet rolls over, explodes, and reveals Luke's face. Unfortunately, Luke ignores this omen in his decision to depart from Dagobah to attempt to save Han Solo, Leia, and company from the Empire. Yoda advises Luke to have patience and not to follow his ego and abandon his training to save them "if you honor what they fight for." Alas, Luke's ego once again inhibits his submission to the Force, preventing his access to its benefits and power. The cave also represents the descent component of the hero cycle (Campbell).
Anger, a major associate of the brash, youthful egotism that Luke characterizes throughout The Empire Strikes Back, also contributes to Luke's failure in Episode V. Obi-Wan Kenobi, Luke's mentor in the ways of the Force from Star Wars Episode IV: A New Hope, heeds that Luke "not give into hate; if you choose to face Vader, you will do it alone." By giving into his rage, Luke ends his training to "become an agent of evil" that Vader and the Emperor can temporarily use for his martial skills. Yoda acknowledged that only a fully trained Jedi could channel the Force to conquer Vader and Emperor Palpatine, but Luke insisted on his youthful rage causing premature evacuation. Luke's ego tells him he "feels the Force," but as Obi-Wan realized, he "cannot control it."
Luke's egotism culminates in his gallant yet foolish clash with Darth Vader after arriving in Cloud City too late to prevent the Empire and Boba Fett from freezing Han Solo in carbonite. Han, by the way, also experiences certain conflicts with his ego throughout the film in his attempts to woo Princess Leia (Luke's sister). Just as in the cave on Dagobah, Luke draws his saber before his opponent, indicating an egotistic aggression resulting in self-destruction. Everything Luke craved that Yoda declared a Jedi would never require (adventure, excitement, heroism, et cetera) appeared truly empty when Vader beat him in three stages of a violent duel. Ultimately, Luke's ego would lose him one hand and many opportunities to serve the Rebel Alliance to his full potential. Luke's premature quest to defeat other enemies only led him to defeat himself, but he would return in the following film with many applicable lessons under his belt and much less of an ego under the hood of his Jedi robe.