Arthur Koestler Quotes about Philosophy
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"The Sleepwalkeers: A History of Man's Changing Vision of the Universe". Book by Arthur Koestler, 1959.
Arthur Koestler (2017). “The Sleepwalkers: A History of Man's Changing Vision of the Universe”, p.27, Penguin UK
Arthur Koestler (1981). “Kaleidoscope: essays from Drinkers of infinity, and The heel of Achilles and later pieces and stories”, Vintage