In Flaubert’s literary universe, intellectual pretensions are often derided as stupidity in disguise. With a mix of fascination and rejection, Flaubert explores the many facets of stupidity and lays bare its key symptoms: vanity, literality, automatism, and animality. By attacking bourgeois stupidity and valorizing idiocy as genuine simplicity, Flaubert reassesses the powers of the mind. In contrast to contemporary metaphysical conceptions of the mind as sovereign, he develops a continuist and immanent approach that links intelligence and idiocy. At the same time, he asserts the mind’s ability to counter the inertia of stupidity through the practice of irony and aesthetic transfiguration.