"Geometry enlightens the intellect and sets one’s mind right. All of its proofs are very clear and orderly. It is hardly possible for errors to enter into geometrical reasoning, because it is well arranged and orderly. Thus, the mind that constantly applies itself to geometry is not likely to fall into error. In this convenient way, the person who knows geometry acquires intelligence." (Ibn Khaldun, "The Muqaddimah: An Introduction to History", 1377)
"[...] the public is composed of the class or classes directly addressed by any work, and not of the heterogeneous mass of readers. Mathematicians do not write for the circulating library. Science is not addressed to poets. Philosophy is meant for students, not for idle readers. If the members of a class do not understand--if those directly addressed fail to listen, or listening, fail to recognise a power in the voice--surely the fault lies with the speaker, who, having attempted to secure their attention and enlighten their understandings, has failed in the attempt? The mathematician who is without value to mathematicians, the thinker who is obscure or meaningless to thinkers, the dramatist who fails to move the pit, may be wise, may be eminent, but as an author he has failed." (George H Lewes, "The Principles of Success in Literature", 1865)
"Everything is so arranged that the blind logic of mathematics executes the will of the most enlightened and free Mind." (Pierre L Maupertuis, "Les Loix du Mouvement et du Repos, déduites d'un Principe Métaphysique", 1746)
"The mystery that clings to numbers, the magic of numbers, may spring from this very fact, that the intellect, in the form of the number series, creates an infinite manifold of well distinguishable individuals. Even we enlightened scientists can still feel it e.g. in the impenetrable law of the distribution of prime numbers." (Hermann Weyl, "Philosophy of Mathematics and Natural Science", 1927)