8 stages overall of psychosocial development: trust v mistrust, autonomy v shame/doubt, initiative v guilt, industry v inferiority, identity v role confusion, intimacy v isolation, generativity v stagnation, integrity v despair
believed that every human goes through a certain number of stages to reach his/her full development, theorizing 8 stages, that a human goes through birth to death; each stage is marked by a conflict, for which successful resolution will result in favorable outcome; only when both extremes are understood/accepted as both required/useful can optimal virtue for stage surface