An Essay Concerning Human Understanding: Complete and Unabridged in One Volume

"An Essay Concerning Human Understanding" is one of John Locke's famous works. First appearing in 1690, the essay concerns the foundation of human knowledge and understanding. The essay was one of the principal sources of empiricism in modern philosophy and influenced many enlightenment philosophers. Book II sets out Locke's theory of ideas, including his distinction between passively acquired simple ideas, such as "red," "sweet," "round," etc., and actively built complex ideas, such as numbers, causes and effects, abstract ideas, ideas of substances, identity, and diversity. He also offers a theory of personal identity, offering a largely psychological criterion. Book III is concerned with language, and Book IV with knowledge, including intuition, mathematics, moral philosophy, natural philosophy ("science"), faith, and opinion.