The most important aspect of ...

The most important aspect of freedom of speech is freedom to learn. All education is a continuous dialogue - questions and answers that pursue every problem on the horizon. That is the essence of academic freedom.
The most important aspect of freedom of speech is freedom to learn. All education is a continuous dialogue - questions and answers that pursue every problem on the horizon. That is the essence of academic freedom.
 William O. Douglas

More phrases

All the great things are simple, and many can be expressed in a single word: freedom, justice, honor, duty, mercy, hope.
I know but one freedom and that is the freedom of the mind.
 Antoine de Saint-Exupéry
Freedom is not worth having if it does not connote freedom to err.
The amount of happiness that you have depends on the amount of freedom you have in your heart.
 Thích Nhất Hạnh
Without freedom of thought, there can be no such thing as wisdom - and no such thing as public liberty without freedom of speech.

Quotes from the same author

No matter what the legislature may say, a man has the right to make his speech, print his handbill, compose his newspaper, and deliver his sermon without asking anyone's permission. The contrary suggestion is abhorrent to our traditions.
 William O. Douglas
The Court's great power is its ability to educate, to provide moral leadership.
 William O. Douglas
Motion pictures are of course a different medium of expression than the public speech, the radio, the stage, the novel, or the magazine. But the First Amendment draws no distinction between the various methods of communicating ideas.
 William O. Douglas
I have the same confidence in the ability of our people to reject noxious literature as I have in their capacity to sort out the true from the false in theology, economics, or any other field.
 William O. Douglas
Man must be able to escape civilization if he is to survive. Some of his greatest needs are for refuges and retreats where he can recapture for a day or a week the primitive conditions of life.
 William O. Douglas