The process of a child’s development consists of acquiring knowledge, which requires the development of his capacity to grasp and deal with an ever-widening range of abstractions. This involves the growth of two interrelated but different chains of abstractions, two hierarchical structures of concepts, which should be integrated, but seldom are: the cognitive and the normative. The first deals with knowledge of the facts of reality—the second, with the evaluation of these facts. The first forms the epistemological foundation of science—the second, of morality and of art.

- Ayn Rand. The Romantic Manifesto (1969).