Id * Ego * Superego
“Sigmund Freud conceived of the personality as consisting of three interrelated influences. The Id is a person’s natural instincts and desires, such as to procreate, to eat and to survive. The Ego uses reason to mediate between reality and the Id, so one might say that in today’s world I can only afford two children, or there are six people needing to eat so I can’t have the whole chicken. Lastly, there is the Superego, akin to the conscience, and thought to originate as an internal version of what parents, school, and society teach. This introduces the concept of ‘I should’–for example, share my good fortune with those less fortunate than myself.”
Excerpted from: Rogerson, Barnaby. Rogerson’s Book of Numbers: The Culture of Numbers–from 1,001 Nights to the Seven Wonders of the World. New York: Picador, 2013.