“But some characters in books are really real--Jane Austen's are; and I know those five Bennets at the opening of Pride and Prejudice, simply waiting to raven the young men at Netherfield Park, are not giving one thought to the real facts of marriage.”

Pudd'nhead Wilson's New Calendar, Ch. LIX
Following the Equator (1897)

Rex Stout, page 244
Invitation to Learning

Source: Match Me If You Can

Source: Book of a Thousand Days

The Paris Review interview (1994)
Context: When people ask me about LSD, I always make a point of telling them you can have the shit scared out of you with LSD because it exposes something, something hollow. Let’s say you have been getting on your knees and bowing and worshiping; suddenly, you take LSD and you look and there’s just a hole, there’s nothing there. The Catholic Church fills this hole with candles and flowers and litanies and opulence. The Protestant Church fills it with hand-wringing and pumped-up squeezing emotions because they can’t afford the flowers and the candles. The Jews fill this hole with weeping and browbeating and beseeching of the sky: How long, how long are you gonna treat us like this? The Muslims fill it with rigidity and guns and a militant ethos. But all of us know that’s not what is supposed to be in that hole. After I had been at Stanford two years, I was into LSD. I began to see that the books I thought were the true accounting books — my grades, how I’d done in other schools, how I’d performed at jobs, whether I had paid off my car or not — were not at all the true books. There were other books that were being kept, real books. In those real books is the real accounting of your life.

Vol. I, Ch. 27, pg. 803.
Das Kapital (Buch I) (1867)

Variant: Sometimes I don't know whether Zelda and I are real or just characters in one of my novels.