In his Tree of Knowledge (ToK) System, Henriques (2003) posits that the human ego or “self” has evolved because human beings are the only animals that have had to justify their behavior to others. This essay provides evidence for this Justification Hypothesis (JH) from everyday life sociology, starting with the work of George Herbert Mead and Charles Horton Cooley, and focuses on research related to the concept of the “looking-glass self.” Special emphasis is given to the pragmatics of speech acts, the presentation of self in interaction rituals, the accounts given by actors in justification of their actions, and the role of social norms and conformity in the large-scale justification systems commonly called “culture.” © 2004 Wiley Periodicals, Inc. J Clin Psychol.