Philosophy, Russell argues in An Outline of Philosophy, is concerned with the universe as a whole. Humanity demands consideration solely as the instrument by which we acquire knowledge of the universe. Russell illuminates the ways in which we are capable of knowledge and discovering natural laws with a discussion of perception, memory, learning in infants and animals and linguistic ability. He moves on to a study of the physical world and then to a discussion of humanity as it sees itself. Finally Russell considers some of the great philosophers of the past and what philosophy has to say about humanity’s place in the universe.