As Boileau said, “La réalité n’est pas toujours vraisemblable.” Reality is not always probable, or likely. But if you’re writing a story, you have to make it as plausible as you can, because if not, the reader’s imagination will reject it.

Jorge Luis Borges (1899-1986) Argentine writer

Discussion published in the Columbia University Forum (1971)
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Often quoted without the first sentence, referring to Boileau, making it seem as if it is purely Borges' statement.