PART I - ESTABLISHING CHESTERTON'S MYSTICISM
CHESTERTON'S MAKESHIFT MYSTICAL THEORY
It would be opportune at this point to present, in his own words, Chesterton's vision of reality, which I claim flowed from a mystical grace.
"Real mystics," he once wrote, "don't hide mysteries, they reveal them. They set a thing up in broad daylight, and when you've seen it, it is still a mystery. But the mystagogues hide a thing in the darkness and secrecy, and when you find it, it's a platitude." 
As a real mystic, what did Chesterton reveal? It was his central preoccupation to unveil the realities we see with our eyes. His mystical doctrine concerns seeing reality with open eyes, the eyes of faith. He experienced God mostly in created reality itself. He believed there was something wrong with our eyes which blocked our vision of reality. It was his sublime calling to open our eyes again.
Very early, through his encounter with Impressionism (which was for him a kind of dark night of the soul), he says that he formulated, in the throes of this darkness, his own "makeshift mystical theory". I don't know which came first, the theory or the mystical experiences, but here is what he said:
This is the heart of his mysticism, and it arose out of his own encounter with nothingness - and grace.
Wonder and the Wooden Post
I find Chesterton's reflections on mysticism in "Wonder and the Wooden Post", especially helpful for my purposes.
One day he accidentally banged his head against a post. This experience helped him to see "a truth about the mysteries and the mystics which I have half known all my life." It was an encounter with reality that led him to reflect upon mysticism and mystics.
First of all, he lists attitudes in his own life which indicate
He then begins a discussion of what we might call "mystics who do not see what he sees."
The reflection of reality in the mind is not the same as the reality itself. There is a danger - not often avoided - that the more a person gazes upon this inner reality, the more it can dwindle into insignificance, to the point where one is no longer moved by it, for good or ill. One of the perennial criticisms of mysticism is that it cuts one off from outer reality, makes one live in an unreal world -- or at least removes one from this outer world. The inner world becomes so absorbing that the outer world dwindles away into a fine point of abstraction and/or unreality.
Not only that, but this inner world poses a further danger for the modern mind which is not penetrated by faith. The realities of the world actually become something else in the mirrors of the mind that is cracked, curved, and distorted.
It should be noted that Chesterton is concerned in these passages with the false mystic observing himself. Elsewhere he says that the saints emphasized two things in looking inward: that the self was a window -- not a mirror --letting through the face of God; and that they were primarily interested in cleaning the window through repentance.
"All my mental doors open outwards." What a refreshingly strange and unexpected statement to come from an intellectual! For all his intellectual brilliance, Chesterton was in dread of having his mental powers disconnected from reality; in dread of not returning to actual reality -- the thing that is marvellous in our eyes. For this reason it would be a misnomer to describe him as an "intellectual mystic."
Chesterton goes on about the wooden post:
This paragraph also reveals the essence of Chesterton's mysticism. In his view, we cannot explain why anything is; we are aware that we are neither creating it nor keeping it in existence; we do not know where anything comes from; it is simply stupendous that anything at all exists. This is why, as he says, "facts are fantasies":
Chesterton was amazed at existence itself -- the it-is-thereness of things, the fact that things simply are. I'm sure that the as yet unrecognized Presence was in his heart when, as a young man of 20, in 1894, he penned the following poem, entitled "In the Evening":It is the little brown hour of twilight
I pause between two dark houses,
For there is a song in my heart.
If I could sing at this moment what I wish to sing,
The nations would crown me,
If I were dumb ever afterwards.
For I am sure it would be the greatest song in the world,
And the song every one has been trying to sing
But it will not come out.
Even after Chesterton tears the veil away from the realities that stare us in the face, they remain mysteries. By showing us the splendour of existence, he does not explain away its mystery. On the contrary, actual realities become a most surprising sacrament of the Presence. Even the organs through which we apprehend reality are more astounding than what we apprehend. What we need is a grace of distance, something sharp and powerful that will cleave us from the miracles that are so close we cannot see them:
The Sword of Surprise
Sunder me from my bones, O sword of God,
Sunder me from my blood that in the dark
Give me miraculous eyes to see my eyes,
The Word of God is called a "sword" in the scriptures. Chesterton prays that the Lord, the Word of God, act as a sword and sever him from the blindness which prevents his seeing the splendour of immediate reality. The concluding stanza is a beautiful prayer for a compassionate love of oneself, that is, for the grace to see ourselves as we see our neighbor:
Sunder me from my soul, that I may see
That our eyes are sundered from the marvels of immediacy is a theme of one of Chesterton's very early writings in Coloured Lands (1912).
Tommy is sitting outside and is bored with the bare, white-washed wall of the cottage; bored with the blank blue of the summer sky; bored with the dull yellow of the thatched roof; bored with the irritatingly straight row of flower pots; bored with the red of the flowers; bored with the greenness of the grass. Grown-up people in this state of mind "go away and write books about their view of the whole world." But Tommy was just ten years old, and couldn't do that.
A strange-looking young man comes along and says he's Tommy's brother (his deeper self?) He says he knows how Tommy feels because he felt like that once himself. He thought if he could make the world all one colour, his favourite colour, he wouldn't be bored. (The Magicians want to "control the elements.") A Wizard gave him different colored glasses of his choice, but he still wasn't satisfied.
And then the miracle happened. The Wizard was tired of the young man's grumbling and told him to make things the colour he liked.
And with that he turned so sharply that Tommy had no time to turn and see him jump over the hedge; for Tommy remained staring at the cottage, with a new look in his eyes. 
One of the causes of our boredom is the belief that reality has just randomly been thrown together, without any rhyme or reason; or that it is like a machine that is getting old and rusty. If we believed that each colour was the choice of a Great Artist, we would see everything with new eyes of wonder, as if we were looking at pictures at an exhibition.
Chesterton's mystical doctrine is not a romantic, humanistic materialism. There is an Artist behind the colours, just as there is a Director behind the play. Objects are not hard, like bolts, but fluid, like paint. The things we see with our eyes are immediate dabs of the Artist's brush, and events the spontaneous directives from the Director. We are involved in an on-going drama, immersed in a play which is in the process of being acted out. When Tommy realized that the colours he was seeing were the result of an actual choice on somebody's part, he had a new look in his eye.
The poem Chesterton singles out in his Autobiography to exemplify the dawning of this luminous realization "was one called `The Babe Unborn,' which imagined the uncreated creature crying out for existence and promising every virtue if he might only have the experience of life." "The Babe Unborn" occupied the first place in The Wild Knight. Here are the last two, poignant verses:
If we can speak of a "born again Gilbert", this rebirth probably happened during his time of darkness, when, as a young man, he realized -- I contend through a mystical grace -- that simply being born, his own passage from nothingness to being, was the greatest miracle of all.
Quoted by Marshall McLuhan in G.K. Chesterton: A Half-Century of Views, ed. Denis Conlon, 1.
 Autobiography, 94-95.
 The Coloured Lands, 1912.
 Ibid., 160-161.
 Ibid., 86.
 The Works of G.K. Chesterton, The Wordsworth Poetry Library, 49.
 Lands, 29-30.
 Wordsworth Poetry Library, 243.