“We find in the history of ideas mutations which do not seem to correspond to any obvious need, and at first sight appear as mere playful whimsies — such as Apollonius' work on conic sections, or the non-Euclidean geometries, whose practical value became apparent only later.”
            as quoted by Michael Grossman in the The First Nonlinear System of Differential and Integral Calculus (1979). 
The Sleepwalkers: A History of Man's Changing Vision of the Universe (1959)
        
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Arthur Koestler 25
Hungarian-British author and journalist 1905–1983Related quotes
                                        
                                        under Hipparchus, Menelaus and Ptolemy 
A History of Greek Mathematics (1921) Vol. 1. From Thales to Euclid
                                    
Geometry as a Branch of Physics (1949)
Source: Mathematical Thought from Ancient to Modern Times (1972), p. 454
Geometry as a Branch of Physics (1949)