“”Answering the Question: What is Enlightenment?” (German: “Beantwortung der Frage: Was ist Aufklärung?”) is the title of a 1784 essay by the philosopher Immanuel Kant. In the December 1784 publication of the Berlinische Monatsschrift (Berlin Monthly), edited by Friedrich Gedike and Johann Erich Biester, Kant replied to the question posed a year earlier by the Reverend Johann Friedrich Zöllner, who was also an official in the Prussian government. Zöllner’s question was addressed to a broad intellectual public, in reply to Biester’s essay entitled: “Proposal, not to engage the clergy any longer when marriages are conducted” (April 1783) and a number of leading intellectuals replied with essays, of which Kant’s is the most famous and has had the most impact. Kant’s opening paragraph of the essay is a much-cited definition of a lack of Enlightenment as people’s inability to think for themselves due not to their lack of intellect, but lack of courage.” (Wikipedia)

Complete English translation of Kant’s essay here.