“The lunatic is all idée fixe, and whatever he comes across confirms his lunacy. You can tell him by the liberties he takes with common sense, by his flashes of inspiration, and by the fact that sooner or later he brings up the Templars.”
Source: Foucault's Pendulum
Help us to complete the source, original and additional information
Umberto Eco 120
Italian semiotician, essayist, philosopher, literary critic… 1932–2016Related quotes

"Donkeys," said Nasrudin.
N. Hanif (ed.), Biographical Encyclopaedia of Sufis: Central Asia and Middle East (2002), ISBN 8176252662, p. 335

“He has no talent at all, that boy! You, who are his friend, tell him please to give up painting.”
spoken to Claude Monet about Pierre-Auguste Renoir (1874), as quoted by John Rewald, The History of Impressionism, Vol.1 (1961).
1850 - 1875

“You can always tell a detective on TV. He never takes his hat off.”
Source: Playback (1958), chapter 14

“He takes the strangest liberties —
But never takes his leave!”
"My Familiar".

In a letter to Ada Leverson [Sphinx] recorded in her book Letters To The Sphinx From Oscar Wilde and Reminiscences of the Author (1930)

Isaac Newton, cited in The Watchtower magazine, 1977, 4/15.