You still can't explain the Force any better. You only describe what it does not what it is.
It's an energy field, created by life, that pervades the universe. That is what it is. That's pretty much all we can say about energy fields. Gravity is a field created by mass that pervades the universe. Electromagnetism is a field created by charged particles that pervades the universe. They can be usefully characterized by observations of what they do, and once you understand what they do, you can create a model that describes their place in the universe. F=Gm1m2/d^2. Therefore, gravity is a field that causes masses to accelerate towards each other. Yoda uses the Force to lift an X-wing and spy on Luke. Therefore, the Force is a field that can be consciously manipulated to do work and perceive the universe independent of sense organs. Can our observations of the Light be used to construct a useful model of how the Lost universe works? Does it make the Lost universe more coherent, or needlessly complex?
I initially brought up Tolkien but then I realized it doesn't apply because he wrote the Silmarillion which is basically an encyclopedia.
The Silmarillion comprises text printed on paper and bound between paper or boards, that's about all it has in common with an encyclopedia.
The power of the ring is not specifically explained in the Lord of the Rings story itself.
Sure its power is specifically explained in
The Lord of the Rings. It "rules" and "binds" the other rings and "ensnares" their bearers (Shadow of the Past). If returned to Sauron, the other ring bearers would be "laid bare" to him (Mirror of Galadriel). It inspires tyranny in its bearers and sets them up to be Dark Lords (Shadow, Council of Elrond). It is "fraught with all his malice; and ... a great part of his strength of old" (Council). "All that was made or begun with that power" depends on it. Its destruction would leave Sauron nothing more than an impotent spirit (The Last Debate). It might even have enough sentience to talk (Mount Doom). This is all a fairly consistent description of a powerful, evil spirit injecting his essence into a physical object, and that object having a mental effect on other beings.
What may not be explained is the origin or nature of that power, or how it functions. But that doesn't
need to be explained in LotR, because LotR is part of a larger work that comprises myth, history, epic verse, metaphysics, etc. It was always intended to be just one of many stories in the Arda cycle. Within that cycle, it functions as an epic. Other parts of the cycle function as myth or metaphysics, and the interested reader is free to consult them to explore the Arda cycle's cosmogony, theology, etc.
Lost is not part of a larger work; it is complete and whole, and must stand or fall on its own merits.
Why not? They're part of the canon. They're part of
The Lord of the Rings. Tolkien wrote them and sent them to his publisher and said "Here is another part of The Lord of the Rings, George," and they have been published as an integral part of the novel since the beginning. You can't selectively ignore parts of LotR that you don't like. I mean, you can certainly ignore them, but you can't ignore them and have an intelligent conversation about LotR. (I am guilty of this in Star Wars: I ignored the Prequels in my earlier comment because I am not very familiar with them.)
But the point of Lost wasn't to explain the Light. That's not what the story was about.
When you write an elephant into a room, and the elephant is magic and its powers and its apparent purpose change every year, and it is impressed upon the characters that the elephant is dreadfully important and the entire reason they have been in the room for six years is to protect the elephant, and your finale is largely about attempts to destroy or save that elephant, then it is disingenuous wave away any criticism of the elephant by saying the story was not about the elephant.
