Aristotle's idea that living things have potentials in need of actualization is the bedrock of Humanistic psychology as well as the basis of the U.S. Army commercial that urges young people to “be all that you can be.” The notion of individual fulfillment, however, has seen its ups and downs.

Following the Classical Greek period of Socrates, Plato, and Aristotle, Athens was conquered by the Roman Empire. Constantine, one of the early Roman emperors, accepted Christianity as did most of the later emperors and within a few hundred years almost the whole of Europe was ruled by the Church. For most of Christianity's first 1,000 years, the idea of fulfillment had nothing to do with individuality or human potentials but rather eternal salvation; that is, happiness is not of this world but lies only in the next.

Psychologist Roy Baumeister reviewed the history of the concept of self and found that with the exception of a just a few writers, interest in human uniqueness was absent during the Middle Ages and did not reappear until the Romantic era of the late eighteenth and early nineteenth centuries. Baumeister notes, “The Romantic era is perhaps best known for its quests to replace Christian salvation with viable, secular images of human fulfillment in life on earth.” Elsewhere he says, “The Romantic era is well known for its experimentation with new ideas of human fulfillment. These focused on work, especially in art and literature, and subjective passion, especially love. In addition, a vague but important interest in the cultivation of ones inner qualities emerged.”