So, I loved the finale, but I am not looking to get into an argument with anyone but here a couple of observations about what was in the finale. Some have been posted before but I am trying to collect them all here.
So there are two huge huge macro theories/nuggets that they gave us in the finale to allow us to decode many of the answers in the show. Some have missed these.
1) the first is with the source. they have explained the source vaguely throughout, primarily because they want to leave it to interpretation. However, in the finale they go out of their way to make a comparison to the source and the hatch. They use similar shots of what it was like for Jack and Locke to look down it. Also Locke mentions the similarity. But is that it?
I feel pretty strongly that as some have mentioned earlier that the show is telling us that the source room is an ancient "station" built with the purposes of controlling a massive pocket of electromagnetic energy, just like the hatch. Mother gives us a spiritual answer to what the source is, but here is a possible scientific explanation.
Imagine an ancient culture (long before Jacob) finds a massive pocket of energy. (we know that the statue and various other relics are older that Jacob). They dig and it starts doing horrible things. They don't understand the science so they plug it up and then they do what they always do with things they don't understand... they worship it, and assign a protector.
As built most effectively in Across the Sea, the way that the writers chose to address island phenomena is by creating a sense that instead of it being random, it merely has always been happening over and over again. In that episode we see ancient men fight over science and faith, kill mothers, "purge" men, lie, make rules to games, con each other (if you interpret mother as taking the form of Claudia), and a whole lot more. Apparently the ancient cultures have made hatch like things before too.
Another reason to prove why I think this is what the writers were thinking is to realize that Desmond once again was the one who had to "pull the plug to save us all", just like he had to push the button. Also when Jack puts the plug back and waits for things to stop shaking, his expression is really similar to when john locke stopped pushing the button, but eventually Jack's faith is rewarded as water starts flowing down.
I feel like this is all one way of explaining it. there is also a spiritual explanation from mother and Jacob. I believe that it is both, but I won't touch on the spiritual until my next part.
Okay, theres more I noticed about that but moving on...
(again sorry if everyone noticed this stuff, I just haven't been seeing it many other places.
2) The second is the vending machine with Juliet and sawyer. While a touching moment, it is also a sly parable for the source. Juliet tells sawyer to get his unstuck candy bar by unplugging and plugging back in the vending machine. When Sawyer unplugs it, all the lights go out (as a fuse blows) but this is pretty clearly exactly what they do to fix the problem of the man in black. They unplug the island, so his soul so to speak can be unstuck, and he can become mortal.
More proof, the candy bar right next to the apollo bar in the machine is called the "avalon" bar. Avalon is I believe a norse mythological purgatory. So I believe (according to mother's spiritual explanation of the source)that the source is some sort of gate to the afterlife (the color of the light in purgatory is similar to the light of the source?) and that the man in black's soul was "Stuck" making him immortal and he just needed a reboot.
To be fair this scene could be interpreted in more ways, but I have no doubt its important.
Final thoughts
So basically, I think lost answered its questions (not all of them) but many with comparisons and metaphors, as well as making things seem like they repeat. This is why there are so many ancient things on the island. They want us to feel like this conflict had history and these essential conflicts have happened again and again.
This is why I don't need explanation of walt. The man in black was special (he saw dead people) and there will always be special people (hurley, miles, and walt). Yes the answer is there just are... but I think its more satisfying when I can say there just are but there always have been.
Also in "the man behind the curtain" they mention an inactive volcano on the island, that could have something to do with the source.
Oh and finally does anyone think that when Echo died, and they flash to him with his brother as children walking into the sunset, its their purgatory?