What is enlightenment? In a 1784 essay with that question as its title, Immanuel Kant answered that it consists of “humankind’s emergence from its self-incurred immaturity,” its “lazy and cowardly” submission to the “dogmas and formulas” of religious or political authority.1 Enlightenment’s motto, he proclaimed, is “Dare to understand!” and its foundational demand is freedom of thought and speech.