My thinking is that meaning never comes from the component pieces of something, but flows downward from the greater into the smaller.
Take Tolkien’s poem. There is no requirement for the collection of molecules that make up a tree to be considered a meaningful thing called a “tree.” Two atoms that happen to be stuck together have no more inherent meaning than two different atoms located at opposite ends of the universe. (I’m actually not that interested or knowledgeable about science, so don’t get caught up in the model of the universe. It’s just an object lesson.)
Meaning doesn’t exist apart from creativity, and shared meaning can’t exist apart from communication. Trees are trees because they represent something meaningful to us, and we label them as a distinct thing. Presumably, some pre-historic human one day had the creative revelation that a tree is a meaningful entity with a distinct place in the cosmos. (The Creation story in Genesis has Adam naming the animals.)
I feel that all meaning is a revelation of the eternal, pre-existing meaning that is my clearest and deepest understanding of God. (“In the beginning was the Word.”) I imagine that atheists might explain primeval humans’ coining of a concept of a tree based on what they used trees for in their habitat for evolutionary advantage, and I have neither the education nor the inclination to argue against that. (I’m not trying to be an apologist here.) However, I believe that if our created meanings are not drawn from some transcendent Truth, then ultimately there is no reason to value anything at all.
Listening to the Gamechurch podcast interviewing ex-Christian atheist Scott Benson, I realized that I’m more nihilistic than the atheists. Nothing matters. The empty universe doesn’t care about progress, or justice, or community mores. The belief that the state of being alive is a preferable condition for a human organism than the state of being dead is arbitrary. There are social ethics and cultural narratives, but there is no reason for their savage betrayal to be inherently worse than their observance. Obviously some people find meaning in the things themselves, enough meaning to be motivated to live good lives and to make the world a better place. I can’t find that meaning without believing in God.
The Word became flesh. To me, the Christian Incarnation means that the River of meaning was born into human history. One corollary is that the intangible inspiration behind all the mythologies actually became real. I’m not a fundamentalist. (Though nearly ever day I worry whether I should be.) I believe that in Christ, the truest meaning behind all the narratives and myths and religions, so far as they reflected divine Truth, came true. As Tolkien wrote in the end of On Fairy Stories, all tales may yet come true.
So… I don’t actually know if that’s what Christian Existentialism is. But its what I believe.