BEN: You will go to the Dagobah system. LUKE: The Dagobah system? BEN: There you will learn from Yoda, the Jedi Master who instructed me.
Man, we wish our mentors would appear to us in trippy dream sequences. It would make picking out outfits way easier. Jokes aside, the ball is now in Luke's court—he now must make the decision to either follow fate or defy it.
LUKE: There's nothing wrong, R-2, I'm just setting a new course. We're not going to regroup with the others. We're going to the Dagobah system.
Although the film spends a lot of time talking about "fate" and "destiny," it must be noted that Luke makes the choice to go to Dagobah. He could have easily ignored Ghost Obi-Wan's advice and gone about his merry, lightsaber-swinging way, but he decides to take his fate into his own hands.
LUKE: There's something familiar about this place.
When Luke first comes on Dagobah, he can't shake the feeling that he's been there before, which further emphasizes the idea that his arrival was destiny.
EMPEROR: We have a new enemy—Luke Skywalker. [...] He could destroy us. VADER: He's just a boy. Obi-Wan can no longer help him. EMPEROR: The Force is strong with him. The son of Skywalker must not become a Jedi.
The Emperor must not have read many Greek tragedies because if he had he would've known that trying to bypass fate through murder and general villainy always backfires. In addition, Vader's reluctance to accept the implications of the Emperor's prophecy subtly foreshadows the revelation that he is Luke's father.
YODA: It is the future you see. LUKE: The future? Will they die? YODA: Difficult to see. Always in motion is the future.
This is important, as it's our first indication that fate isn't exactly—well—fated. Think of it like forecasting a hurricane: It's pretty easy for meteorologists to figure out a range of possible paths for a storm, but it's a lot harder to narrow it down to one.
LUKE: I can't keep the vision out of my head. They're my friends. I've got to help them. YODA: You must not go! LUKE: But Han and Leia will die if I don't. OBI-WAN: You don't know that. Even Yoda cannot see their fate.
Despite Yoda and Obi-Wan's vehement protestations, Luke refuses to abandon his friends to Vader. Once again, this represents Luke actively taking his fate into his own hands, ignoring prophecies and destinies and all of that hogwash and simply focusing on the here and the now. Sounds like a Jedi to us.
YODA: Told you, I did. Reckless is he. Now matters are worse. OBI-WAN: That boy is our last hope. YODA: No. There is another.
This certainly changes things, doesn't it? While most people interpret this scene as referring to Leia (although there is debate over whether Leia was intended to be Luke's sister at the time of Empire's release), the important part is that it once again upends the concept of fate—or at least complicates it.
VADER: Your destiny lies with me, Skywalker. Obi-Wan knew this to be true.
Here's a pro-tip from the experts at Shmoop: If a seven-foot-tall, armor-wearing machine man starts rambling about destiny while trying to stab you with a laser sword, he's probably trying to sell you a bill of goods.
VADER: You do not yet realize your importance. You have only begun to discover your power. Join me and I will complete your training.
Like Yoda and Obi-Wan, Darth Vader is convinced that Luke is destined to change the galaxy—the only difference is that Vader wants to use this for his own benefit. Still, a critical viewer might argue that Yoda and Obi-Wan are no different.
VADER: Luke. You can destroy the Emperor. He has foreseen this. It is your destiny. Join me, and together we can rule the galaxy as father and son.
If Yoda and Obi-Wan were right about Luke's immaturity, then he would've taken this offer, right? How is Luke able to refuse? In the end, the film argues that, although we all must confront destiny, that doesn't mean we don't have a choice. In the words of another great alien-killer: "It ain't over 'til the fat lady sings."