Knowledge

Russell claims in the beginning of The Problems of Philosophy that he has chosen to focus on issues on which he has something constructive to contribute, alongside his criticisms. For this reason, he says, the book has more to say about epistemology, the theory of knowledge, than metaphysics, the theory of being. The book's structure is built around the question of how different classes of facts and things are known.

For instance, the first chapter distinguishes between appearance and reality. We are only directly acquainted with appearances and must know reality through appearances. Russell will go on to argue that knowledge is divided into two general categories: knowledge by acquaintance and knowledge by description.

Knowledge by acquaintance is any knowledge gained from sense-data of material or mental things or of intuitions about universals or other indubitable facts. Knowledge by description is knowledge of the truth of propositions that...