Pareto argues that people can adopt or defend an idea without understanding it in detail when believing it serves their interests. In this account, acceptance of a theory may depend less on careful examination of its arguments than on the practical, social or political advantages associated with it.

The remark reflects Pareto’s broader interest in the difference between the reasons people give for their beliefs and the underlying motives that may influence them. A theory’s name can become a symbol of identity, loyalty or interest even when its content is only vaguely understood.

The quotation does not imply that all beliefs are insincere or purely self-interested. Rather, it highlights the possibility that usefulness can shape conviction independently of knowledge. It can therefore be applied when examining ideological allegiance, public debate or situations in which people adopt labels and doctrines without closely considering what those doctrines actually contain.