Since the release of The Force Awakens, the most common objection from fans to the theory that Rey was Luke’s daughter “Wouldn’t Luke be able to sense that Rey was alive and on Jakku all of that time?” The answer it turns out is no and Lucasfilm already has a built in explanation for why not.
First things first, you have to explain how Rey got to Jakku. “Luke wouldn’t abandon his own child!” is another common objection to the idea of Rey Skywalker that has to be circumvented. Fortunately there is a very easy remedy: Luke wasn’t the one that abandoned her, she was kidnapped and something happened that caused the kidnappers to abandon her. That poses another problem though. If Luke knew his daughter had been kidnapped he would never give up on trying to find her. Why wouldn’t he be looking for her? Well there’s a simple answer to that as well: he didn’t realize she had been kidnapped, he thought that she had been killed. So now the only obstacle is finding a way for Rey to be kidnapped in such a way that Luke would be convinced that she had died. It just so happens that the novel Thrawn: Alliances lays out a way to do just that.
Thrawn: Alliances is split between two stories, one of Anakin and Thrawn during the Clone Wars, the other of Vader and Thrawn during the Rebellion. The story of Vader and Thrawn is about them trying to rescue Force Sensitive Chiss (Thrawn’s species) girls that had been abducted.
Here’s where it gets interesting. When the girls were abducted they were put into hibernation chambers. Just prior to the girls being put in the chambers Vader could sense their fear and distress. However, once they had been put inside he could sense nothing from them. The book makes a point that he couldn’t be sure whether the girls had been put in the hibernation chambers or whether they had been killed.
It’s also worth noting that Zahn added a few other interesting details about these girls. First of all, for the Chiss, only girls are Force Sensitive and they lose their Force Sensitivity as the grow into adulthood. This fact raises some flags because the story of Thrawn and Vader would not be impacted in the slightest if some of the Chiss children were boys and would only need minor modifications if adult Chiss were capable of being Force Sensitive. Secondly, the girls all serve as navigators for Chiss ships flying through the Unknown Regions. Chiss navigators have a title that Thrawn explains translates as Sky-Walker. At this point either Mr. Zahn has something in his eye or he’s winking at us really hard. Let’s put the hints together. How do you kidnap a Force Sensitive little girl Sky-Walker in such a way that one of the most powerful Force users in the galaxy couldn’t sense the difference between her being abducted and her being killed? The book gives the answer: put her in a hibernation chamber.
Rey being abducted in such a way that Luke would think her dead ties up a couple other loose ends as well. The theory: Ben Solo betrayed Luke which led to an attack. Luke hid Rey and told her “I’ll come back, Sweetheart. I promise.” (the line Rey hears a mysterious voice speak during her Forceback in the Force Awakens novelization). Luke then goes to try to save his wife, but she is tragically killed in the attack, which explains why she doesn’t appear in the Sequel Trilogy. While Luke is trying to save his wife, Rey is taken and put in the hibernation tank. Luke feels it as Rey dying. Something happens that makes him not question the absence of her body: an explosion, the collapse of the building where he hid her, maybe one of the attackers has a Mandalorian style disintegration rifle. The point being that Luke at this point is 100% convinced that his child is dead. Fast forward a few years, Luke goes into Ben Solo’s hut and peers into his mind while he’s sleeping. He sees that Ben was in some way responsible for the attack that led to Luke losing his wife and child. Suddenly, Luke drawing his saber in a moment of pure instinct doesn’t seem so out of character, does it?