“Mathematical magic combines the beauty of mathematical structure with the entertainment value of a trick.”

Source: Hyperspace (1995), Ch.15 Conclusion<!--p.328-->
Context: Mathematics... is the set of all possible self-consistent structures, and there are vastly more logical structures than physical principles.

Source: Glory Season (1993), Chapter 24 (p. 466)

Source: Linear programming and extensions (1963), p. 2

As quoted in The Cosmic Code : Quantum Physics As The Language Of Nature (1982) by Heinz R. Pagels, p. 295; also in Paul Adrien Maurice Dirac : Reminiscences about a Great Physicist (1990) edited by Behram N. Kursunoglu and Eugene Paul Wigner, p. xv

Mathematics in Action (1954) page 3

1900s, "The Study of Mathematics" (November 1907)
Context: Mathematics, rightly viewed, possesses not only truth, but supreme beauty – a beauty cold and austere, like that of sculpture, without appeal to any part of our weaker nature, without the gorgeous trappings of painting or music, yet sublimely pure, and capable of a stern perfection such as only the greatest art can show. The true spirit of delight, the exaltation, the sense of being more than Man, which is the touchstone of highest excellence, is to be found in mathematics as surely as in poetry. What is best in mathematics deserves not merely to be learnt as a task, but to be assimilated as a part of daily thought, and brought again and again before the mind with ever-renewed encouragement.

Source: http://www.theguardian.com/science/2014/aug/13/interview-maryam-mirzakhani-fields-medal-winner-mathematician

Conversation with Einstein, as quoted in Bittersweet Destiny: The Stormy Evolution of Human Behavior by Del Thiessen
Context: If nature leads us to mathematical forms of great simplicity and beauty—by forms I am referring to coherent systems of hypothesis, axioms, etc.—to forms that no one has previously encountered, we cannot help thinking that they are "true," that they reveal a genuine feature of nature... You must have felt this too: The almost frightening simplicity and wholeness of relationships which nature suddenly spreads out before us and for which none of us was in the least prepared.

Preface p. v
A History of Greek Mathematics (1921) Vol. 1. From Thales to Euclid