Full Idea
The public use of man's reason must always be free, and it alone can bring about enlightenment among men; the private use of reason may quite often be very narrowly restricted (…in a particular civil post or office).
Gist of Idea
Enlightenment requires the free use of reason in the public realm
Source
Immanuel Kant (Answer to 'What is Enlightenment?' [1784], p.55)
Book Reference
Kant,Immanuel: 'Political Writings', ed/tr. Reiss,Hans [CUP 1996], p.55
A Reaction
The private aspect seems to be the common restriction on speech by employees of the state. Does free speech have only instrumental value? Is the life of virtue possible without it?