“Enlightenment is man’s emergence from his self-imposed immaturity. Immaturity is the inability to use one’s understanding without guidance from another. This immaturity is self-imposed when its cause lies not in lack of understanding, but in lack of resolve and courage to use it without guidance from another. Sapere Aude! ‘Have courage to use your own understanding!’—that is the motto of enlightenment.”

The opening paragraph states the answer to the title question directly and introduces the figurative use of immaturity to describes humanity’s unenlightened state. Kant challenges his readers by telling them that humanity’s immaturity is due to their own failures, not their incapacity. He gives enlightenment a Latin motto that further challenges readers, stressing courage and the importance of Thinking for Oneself. The overall effect is direct and brisk: Kant wants to motivate his readers from the very start of the essay.

“Laziness and cowardice are the reasons why so great a proportion of men, long after nature has released them from alien guidance […], nonetheless gladly remain in lifelong immaturity, and why it is so easy for others to establish themselves as their guardians. It is so easy to be immature. If I have a book to serve as my understanding, a pastor to serve as my conscience, a physician to determine my diet for me, and so on, I need not exert myself at all. I need not think, if only I can pay: others will readily undertake the irksome work for me.”

Kant continues to challenge his readers in the second paragraph. The reader will surely not want to identify as lazy or cowardly, so Kant hopes they will reflect on the ways that they rely on others do their thinking or make their decisions for them. His tone almost conveys contempt for those who do so.

“Having first made their domestic livestock dumb, and having carefully made sure that these docile creatures will not take a single step without the go-cart to which they are harnessed, these guardians then show them the danger that threatens them, should they attempt to walk alone. Now this danger is not actually so great, for after falling a few times they would in the end certainly learn to walk; but an example of this kind makes men timid and usually frightens them out of all further attempts.”

Kant uses the metaphor of unenlightened people as livestock to further raise the stakes of his challenge. People resemble livestock and thus lose their humanity to the degree that they allow others to lead them. Kant shows that he is still confident that people can think for themselves (“this danger is not actually so great […]”) but believes that it is simply lack of resolve or courage that prevents them from doing so.