information:classification
Conceptual origins

The "second force" arose out of Freudian psychoanalysis, which were composed by psychologists like Alfred Adler, Erik Erikson, Carl Jung, Erich Fromm, Karen Horney, Melanie Klein, Harry Stack Sullivan, and Sigmund Freud himself. Maslow then emphasized the necessity of a "third force" (even though he did not use the term), saying that "it is as if Freud supplied us the sick half of psychology and we must now fill it out with the healthy half", as a critical review towards the cold and distant approach of the psychoanalysis and its deterministic way of viewing the human being.