When, almost twenty years later, The Man Who Was Thursday was adapted for the stage,* Chesterton said in an interview:
[* By Ralph Neale and Mrs. Cecil Chesterton.]
In an ordinary detective tale the investigator discovers that some amiable-looking fellow who subscribes to all the charities, and is fond of animals, has murdered his grandmother, or is a trigamist. I thought it would be fun to make the tearing away of menacing masks reveal benevolence.
Associated with that merely fantastic notion was the one that there is actually a lot of good to be discovered in unlikely places, and that we who are fighting each other may be all fighting on the right side. I think it is quite true that it is just as well we do not, while the fight is on, know all about each other; the soul must be solitary; or there would be no place for courage.
A rather amusing thing was said by Father Knox on this point. He said that he should have regarded the book as entirely pantheist and as preaching that there was good in everything if it had not been for the introduction of the one real anarchist and pessimist. But he was prepared to wager that if the book survives for a hundred years—which it won't—they will say that the real anarchist was put in afterwards by the priests.
But, though I was more foggy about ethical and theological matters than I am now, I was quite clear on that issue; that there was a final adversary, and that you might find a man resolutely turned away from goodness.
People have asked me whom I mean by Sunday. Well, I think, on the whole, and allowing for the fact that he is a person in a tale—I think you can take him to stand for Nature as distinguished from God. Huge, boisterous, full of vitality, dancing with a hundred legs, bright with the glare of the sun, and at first sight, somewhat regardless of us and our desires.
There is a phrase used at the end, spoken by Sunday: "Can ye drink from the cup that I drink of?" which seems to mean that Sunday is God. That is the only serious note in the book, the face of Sunday changes, you tear off the mask of Nature and you find God.
Monsignor Knox* has called The Man Who Was Thursday "an extraordinary book, written as if the publisher had commissioned him to write something rather like the Pilgrim's Progress in the style of the Pickwick Papers"—which explains perhaps why some reviewers called it irreverent. The very wildness of it conveys a sense of thoughts seething and straining in an effort to express the inexpressible. Later in his more definitely philosophical books G.K. could say calmly much that here he splashes "on a ten leagued canvas with brushes of comet's hair"—with all the violent directness of a vision.
[* In the panegyric preached at Westminster Cathedral, June 27, 1936.]