“There are those who can prove that plans and ideals for a united world and a well organized Brotherhood of Men have existed for hundreds of years and have come to nothing. These are the ones who say “Human nature cannot change!” There are others who declare that we are living through a momentous epoch in history which is ushering in stupendous changes and the possibility for real world unity and a new and better civilization.”

In Beiruit
Mao II (1991)

2009, Nobel Prize acceptance speech (December 2009)
Context: We do not have to think that human nature is perfect for us to still believe that the human condition can be perfected. We do not have to live in an idealized world to still reach for those ideals that will make it a better place. The non-violence practiced by men like Gandhi and King may not have been practical or possible in every circumstance, but the love that they preached — their fundamental faith in human progress — that must always be the North Star that guides us on our journey.
For if we lose that faith — if we dismiss it as silly or naïve; if we divorce it from the decisions that we make on issues of war and peace — then we lose what's best about humanity. We lose our sense of possibility. We lose our moral compass.
Like generations have before us, we must reject that future. As Dr. King said at this occasion so many years ago, "I refuse to accept despair as the final response to the ambiguities of history. I refuse to accept the idea that the 'isness' of man's present condition makes him morally incapable of reaching up for the eternal 'oughtness' that forever confronts him."
Let us reach for the world that ought to be — that spark of the divine that still stirs within each of our souls.

1850s, Speech at Chicago (1858)
Context: There is something else connected with it. We have besides these men — descended by blood from our ancestors — among us perhaps half our people who are not descendants at all of these men, they are men who have come from Europe — German, Irish, French and Scandinavian — men that have come from Europe themselves, or whose ancestors have come hither and settled here, finding themselves our equals in all things. If they look back through this history to trace their connection with those days by blood, they find they have none, they cannot carry themselves back into that glorious epoch and make themselves feel that they are part of us, but when they look through that old Declaration of Independence they find that those old men say that 'We hold these truths to be self-evident, that all men are created equal,' and then they feel that that moral sentiment taught in that day evidences their relation to those men, that it is the father of all moral principle in them, and that they have a right to claim it as though they were blood of the blood, and flesh of the flesh of the men who wrote that Declaration, and so they are. That is the electric cord in that Declaration that links the hearts of patriotic and liberty-loving men together, that will link those patriotic hearts as long as the love of freedom exists in the minds of men throughout the world.

Some Reflections on Peace in Our Time (1950)

360 Doctrines and Comprehensive Theories, Union of Civilizations

II. Progress and Entropy. p. 46
The Human Use of Human Beings (1950)

Source: Striking Thoughts (2000), p. 21
Context: If thought exists, I who think and the world about which I think also exist; the one exists but for the other, having no possible separation between them. Therefore, the world and I are both in active correlation; I am that which sees the world, and the world is that which is seen by me. I exist for the world and the world exists for me. … One sure and primary and fundamental fact is the joint existence of a subject and of its world. The one does not exist without the other. I acquire no understanding of myself except as I take account of objects, of the surroundings. I do not think unless I think of things — and there I find myself.

360 Doctrines and Comprehensive Theories, Union of Civilizations

Source: Vestiges of the Natural History of Creation (1844), p. 154