Below, is one of my favorite passages from Chesterton’s Orthodoxy (although it is almost impossible to find a favorite!). It comes from his chapter, “The Maniac.” Enjoy!
“There is a notion adrift everywhere that imagination, especially mystical imagination, is dangerous to man’s mental balance. Poets are commonly spoken of as psychologically unreliable; and generally there is a vague association between wreathing laurels in your hair and sticking straws in it. Facts and history utterly contradict this view. Most of the very great poets have been not only sane, but extremely business-like; and if Shakespeare ever really held horses, it was because he was much the safest man to hold them. Imagination does not breed insanity. Exactly what does breed insanity is reason. Poets do not go mad; but chess-players do. Mathematicians go mad, and cashiers; but creative artists very seldom. I am not, as will be seen, in any sense attacking logic: I only say that this danger does lie in logic, not in imagination. Artistic paternity is as wholesome as physical paternity. Moreover, it is worthy of remark that when a poet really was morbid it was commonly because he had some weak spot of rationality on his brain. Poe, for instance, really was morbid; not because he was poetical, but because he was specially analytical. Even chess was too poetical for him; he disliked chess because it was full of knights and castles, like a poem. He avowedly preferred the black discs of draughts, because they were more like the mere black dots on a diagram. Perhaps the strongest case of all is this: that only one great English poet went mad, Cowper. And he was definitely driven mad by logic, by the ugly and alien logic of predestination. Poetry was not the disease, but the medicine; poetry partly kept him in health. He could sometimes forget the red and thirsty hell to which his hideous necessitarianism dragged him among the wide waters and the white flat lilies of the Ouse. He was damned by John Calvin; he was almost saved by John Gilpin. Everywhere we see that men do not go mad by dreaming. Critics are much madder than poets. Homer is complete and calm enough; it is his critics who tear him into extravagant tatters. Shakespeare is quite himself; it is only some of his critics who have discovered that he was somebody else. And though St. John the Evangelist saw many strange monsters in his vision, he saw no creature so wild as one of his own commentators. The general fact is simple. Poetry is sane because it floats easily in an infinite sea; reason seeks to cross the infinite sea, and so make it finite. The result is mental exhaustion, like the physical exhaustion of Mr. Holbein. To accept everything is an exercise, to understand everything a strain. The poet only desires exaltation and expansion, a world to stretch himself in. The poet only asks to get his head into the heavens. It is the logician who seeks to get the heavens into his head. And it is his head that splits.
It is a small matter, but not irrelevant, that this striking mistake is commonly supported by a striking misquotation. We have all heard people cite the celebrated line of Dryden as ‘Great genius is to madness near allied.’ But Dryden did not say that great genius was to madness near allied. Dryden was a great genius himself, and knew better. It would have been hard to find a man more romantic than he, or more sensible. What Dryden said was this, ‘Great wits are oft to madness near allied’; and that is true. It is the pure promptitude of the intellect that is in peril of a breakdown. Also people might remember of what sort of man Dryden was talking. He was not talking of any unworldly visionary like Vaughan or George Herbert. He was talking of a cynical man of the world, a sceptic, a diplomatist, a great practical politician. Such men are indeed to madness near allied. Their incessant calculation of their own brains and other people’s brains is a dangerous trade. It is always perilous to the mind to reckon up the mind. A flippant person has asked why we say, ‘As mad as a hatter.’ A more flippant person might answer that a hatter is mad because he has to measure the human head.
And if great reasoners are often maniacal, it is equally true that maniacs are commonly great reasoners.”
– Chesterton, “The Maniac” from Orthodoxy