Great theories generate numerous testable hypotheses. Engelmann's theory was very successful in that regard. His hypotheses were on target whether about aggression, random violence, cultural closure, anti-intellectualism, diminishing freedoms, or scientific viewpoints. In the late 1960s when riots were common place and everyone blamed everyone else, Engelmann sought answers to questions no one else was asking. Statistically speaking, how do groups emerge? In terms of probability how can they persist? The questions involve two mathematical curves. One represents the likelihood that a subgroup of a specific size will emerge; the other is the probability that it will persist. The product of the two curves provided the answer for the one-third hypothesis in 1967. Those groups most likely to emerge and to persist are the ones that amount to one-third of the total population, whether they be ethnic enclaves in the city, students protesting in the streets, social movements coming to the fore, or local governments on the rise.