Humanistic psychology is based on client-centered therapy and the idea that each individual has the potential to achieve a position in their psyche called self-actualization. Humanistic psychology differs from psychodynamic theory in that it is optimistic about the human psyche and does not view conflict as inevitable. Humanistic psychology assumes that people attach meaning to their unique perspectives on the world and that their behavior is strongly influenced by them. Carl Rogers defined healthy personality as one that exhibits congruence between the perceived self and the experienced self and that the individual in question enjoys unconditional positive respect from his or her parent or guardian. He defined an unhealthy personality as one lacking these elements. Abraham Maslow also suggested a hierarchy whereby a person's healthy personality could be measured by stages of psychological and physical needs (see diagram 2). He suggested that in order for a person to flourish and become a fully functioning person, they must first satisfy all the needs at each level of the pyramid before moving on to the next.