An imagined threat might be an extremely powerful motivation to action; and an aspiration, even if built on fantasy, is not nothing, provided it really moves people to action. … Even illusions can have effects. The realist must take powerful illusions seriously as factors in the world that have whatever motivational power they in fact have for the population in question, that is, as something to be understood. This is compatible with seeing through them, and refusing steadfastly to make them part of the cognitive apparatus one employs oneself to try to make sense of the world.

p. 11. - Philosophy and Real Politics (2008)