Edward Gibbon:

All that is human must retrograde if it do not advance.

Felix Adler:

Ethical religion can be real only to those who are engaged in ceaseless efforts at moral improvement. By moving upward we acquire faith in an upward movement, without limit.

H. L. Mencken:

I believe that liberty is the only genuinely valuable thing that men have invented, at least in the field of government, in a thousand years. I believe that it is better to be free than to be not free, even when the former is dangerous and the latter safe. I believe that the finest qualities of man can flourish only in free air – that progress made under the shadow of the policeman's club is false progress, and of no permanent value. I believe that any man who takes the liberty of another into his keeping is bound to become a tyrant, and that any man who yields up his liberty, in however slight the measure, is bound to become a slave.

HH the Dalai Lama:

Peace, in the sense of the absence of war, is of little value to someone who is dying of hunger or cold. It will not remove the pain of torture inflicted on a prisoner of conscience. It does not comfort those who have lost their loved ones in floods caused by senseless deforestation in a neighboring country. Peace can only last where human rights are respected, where the people are fed, and where individuals and nations are free.

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Henry David Thoreau:

If a man walks in the woods for love of them half of each day, he is in danger of being regarded as a loafer. But if he spends his days as a speculator, shearing off those woods and making the earth bald before her time, he is deemed an industrious and enterprising citizen.

Henry Steele Commager:

Change does not necessarily assure progress, but progress implacably requires change. Education is essential to change, for education creates both new wants and the ability to satisfy them.

James Russell Lowell:

He who is firmly seated in authority soon learns to think security, and not progress, the highest lesson of statecraft.

John Dewey:

Every great advance in science has issued from a new audacity of the imagination.

from The Quest For Certainty

Mark Twain:

Time and tide wait for no man. A pompous and self-satisfied proverb, and was true for a billion years; but in our day of electric wires and water-ballast we turn it around: Man waits not for time nor tide.

Mark Twain:

If I were required to guess off-hand, and without collusion with higher minds, what is the bottom cause of the amazing material and intellectual advancement of the last fifty years, I should guess that it was the modern-born and previously non-existent disposition on the part of men to believe that a new idea can have value.

Thomas A. Edison:

Restlessness and discontent are the first necessities of progress.

W.E.B. Du Bois:

The most important thing to remember is this: To be ready at any moment to give up what you are for what you might become.

Will Rogers:

You can't say civilization don't advance -- for in every war, they kill you in a new way.