"When we represent a group of connections by a closed and coherent set of concepts, axioms, definitions and laws which in turn are represented by a mathematical scheme we have in fact isolated and idealized this group of connections with the purpose of clarification. But... it is not known how accurately the set of concepts describes reality. These idealizations may be called a part of the human language that has been formed from the interplay between the world and ourselves, a human response to the challenge of nature. In this respect they may be compared to the different styles of art, say of architecture or music. A style of art can also be defined by a set of formal rules which are applied to the material of this special art. These rules can perhaps not be represented in a strict sense by a set of mathematical concepts and equations, but their fundamental elements are very closely related to the essential elements of mathematics. Equality and inequality, repetition and symmetry, certain group structures play the fundamental role both in art and in mathematics."