**Major spoilers for 'The Force Awakens' lie ahead, so if you haven't seen it, you know the drill**
Now that I've got your attention, I am fairly convinced that Rey is Luke's daughter, but I also think that Finn will learn the ways of the Force too. My reasoning is five-fold:
J.J. Abrams's Opposition to a Midi-chlorian Bloodline
In an interview, Abrams states:
For me when I heard Obi-Wan say that the Force surrounds us and binds us all together, there was no judgement about who you were. This was something that we could all access. Being strong with the Force didn’t mean something scientific, it meant something spiritual. It meant someone who could believe, someone who could reach down to the depths of your feelings and follow this primal energy that was flowing through all of us. I mean, that’s what was said in that first film! And there I am sitting in the theater at almost 11 years old and that was a powerful notion. And I think this is what your point was, we would like to believe that when s**t gets serious, that you could harness that Force I was told surrounds not just some of us but every living thing. And so, I really feel like the assumption that any character needs to have inherited a certain number of midi-chlorians or needs to be part of a bloodline, it’s not that I don’t believe that as part of the canon, I’m just saying that at 11 years old, that wasn’t where my heart was. And so I respect and adhere to the canon but I also say that the Force has always seemed to me to be more inclusive and stronger than that. SlashFilm
Finn fits that bill beyond perfectly. He was a Stormtrooper. Later in the movie, after learning about the Force, he spoke as one who had faith. When Han asked how they would lower the shields, he answered like a naive child; "We'll use the Force."
People have argued that this is the reason why Rey isn't a Skywalker. However, I think there are too many parallels between her and Luke, which Abrams likely intended. Therefore, it is in Finn that Abrams plays out his views on the average Joe using the Force...
The Light Side of the Force
What is it that suddenly gave Finn, who was raised to be a Stormtrooper since birth, a conviction that what he was trained to do was wrong? Something was prompting Finn that helping Poe was "the right thing to do."
Kylo Ren Sensed It in Him
When Finn (FN-2187) first rejected his orders and did not fire, he later stood there and stared at Kylo Ren from a great distance. Kylo suddenly looks directly at him, and later when Ren was told that a Stormtrooper had assisted Poe's escape, he already knew who it was.
How else could he have known, unless Ren sensed the light in Finn? The Force doesn't make you omniscient.
There Was an Awakening
When Kylo Ren first spoke with Supreme Leader Snoke, Snoke asked him, "There was an awakening. Did you sense it?" And he did. It wasn't Rey, because she wasn't even introduced yet. It must have been Finn. Kylo Ren sensed it in him.
It could be argued at this point that Ren took no interest in the traitor and didn't offer to train him as he did, Rey. However, it may be that he was merely more interested in Rey because she was so powerful, or that he sensed that there was too much light in Finn to turn him to the dark side.
He Fought With a Lightsaber
Finn fought with a lightsaber, and he even held his own against a trained Jedi, Ben/Kylo Ren. He wasn't amazing, mind you, but the fact that he was not simply overpowered immediately says something.
It also makes you wonder why Maz suggested he use the lightsaber when Finn said he needed a weapon. She knows the Force... You don't just hand a lightsaber to someone trained with a blaster and hope for the best.
In addition, Finn using the lightsaber could be a bit of foreshadowing of future events. I know, I'm reaching a bit here...
Star Wars Episode 8 is in theaters May 2017.