Danish Prince

“When we talk mathematics, we may be discussing a secondary language, built on the primary language truly used by the central nervous system. Thus the outward forms of our mathematics are not absolutely relevant from the point of view of evaluating what the mathematical or logical language truly used by the central nervous system is. However, the above remarks about reliability and logical and arithmetical depth prove that whatever the system is, it cannot fail to differ considerably from what we consciously and explicitly consider as mathematics.”
― John von Neumann, The Computer and the Brain

“A large part of mathematics which becomes useful developed with absolutely no desire to be useful, and in a situation where nobody could possibly know in what area it would become useful; and there were no general indications that it ever would be so.”
― John von Neumann

“Philosophy of science is philosophy enough.”
― Willard Van Orman Quine

“Plurality is never to be posited without necessity.”
― William of Ockham, Quaestiones et decisiones in quattuor libros Sententiarum Petri Lombardi