IMMANUEL KANT: 

AN ANSWER TO THE QUESTION: WHAT IS ENLIGHTENMENT? 

Enlightenment is humanity's emergence from its 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 resolution and courage to use it without guidance from another. Sapere aude! Have courage to use your own understanding! This is therefore the motto of the Enlightenment. 

Laziness and cowardice are the reasons why such a large portion of humanity, long after nature has freed them from external guidance (naturaliter maiorennes), nevertheless gladly remain immature for life. And these are the reasons why it becomes so easy for others to set themselves up as guardians. It is so comfortable to be immature. If I have a book that has understanding for me, a pastor who has a conscience for me, a doctor who judges my diet for me, and so on, then I don't need to make any effort myself. I don't need to think, as long as I can pay. Others will take care of that troublesome business for me. 

That the vast majority of people (including the entire "fair sex") consider the step toward maturity not only burdensome but also very dangerous—this is ensured by those guardians who have so kindly taken upon themselves the oversight of these people. After first making their domestic animals stupid and carefully preventing these docile creatures from daring to take a single step outside the pen in which they confined them, they then show them the danger that threatens if they try to walk alone. Now this danger is actually not so great, for they would eventually learn to walk through occasional falls. But an example of this kind makes one timid and usually frightens people away from all further attempts...