This document discusses the distinction between knowledge by acquaintance and knowledge by description as outlined by Bertrand Russell. Knowledge by acquaintance is direct, unmediated knowledge of one's experiences, like being aware of one's own pain. Knowledge by description is indirect or inferential knowledge, like knowing the biochemical structure of one's brain. Russell believed knowledge by acquaintance was the most basic form of knowledge that knowledge by description relies upon, either by using concepts we are acquainted with or by inferring descriptions from our acquaintance with experiences.