[speculator] group is primarily responsible for change, for economic and social progress. The [rentier] group, instead, is a powerful element in stability, and in many cases counteracts the dangers attending the adventurous capers of the [speculators]. A society in which the [rentiers] almost exclusively predominate remains stationary and, as it were, crystallized. A society in which [the speculators] predominate lacks stability, lives in a state of shaky equilibrium that may be upset by a slight accident from within or from without. Like in the governing elite where things work best when both residues of Class I and Class II are represented, so in the economic order maximum effectiveness is attained when both rentiers and speculators are present, each providing a balance by checking the excesses of the other. Pareto implies throughout that a judicious mixture in top elites of men with Class I and Class II residues makes for the most stable economic structure, as well as for the most enduring political structure. References Elite theory Political science terminology Vilfredo Pareto