“There are two kinds of characters in all fiction, the born and the synthetic. If the writer has to ask himself questions — is he tall, is he short?”

Letter to his brother Jeff, from Hawaii (7 April 1941); p. 11
To Reach Eternity (1989)

Like It Was, p.249

Source: Tender Is the Night

Sakharov Prize for Freedom of Thought Acceptance Speech (2013)

Source: Jonathan Strange & Mr Norrell

"Inner Landscape : Interview with J.G. Ballard" by Robert Lightfoot and David Pendleton, in Friends No. 17 (30 October 1970) http://www.jgballard.ca/media/1970_oct_friends_magazine.html; also quoted in The Columbia Dictionary of Quotations (1993) by Robert Andrews
Context: A hundred years ago one has the impression that people had made a clear distinction between the outer world of work and of agriculture, commerce and social relationships — which was real — and the inner world of their own minds, day-dreams and hopes. Fiction on the one hand; reality on the other. This reality which surrounded individuals, the writer's role of inventing a fiction that encapsulated various experiences going on in the real world and dramatising them in fictional form, worked. Now the whole situation has been reversed. The exterior landscapes of the seventies are almost entirely fictional ones created by advertising, mass merchandising… politics conducted as advertising. It is very difficult for the writer.
Given that external reality is a fiction, the writer's role is almost superfluous. He does not need to invent the fiction because it is already there.

[John J. B. Morgan and T. Webb Ewing, Making the Most of Your Life, 2005, 75 http://books.google.fr/books?id=5i-JlfkMEUUC&pg=PA75]
Attributed
Variant: No man really becomes a fool until he stops asking questions.

As quoted in "Master of the Secret World: John le Carré on Deception, Storytelling and American Hubris" by Andrew Ross, in Salon (21 October 1996); also in Conversations with John le Carré (2004) edited by Matthew Joseph Bruccoli and Judith Baughman, p. 140