“At times, it seems to me that to be human is to want that which we cannot have. For some, this is power. For me, it is peace.”

Day One
Dialogue Concerning the Two Chief World Systems (1632)
Context: It always seems to me extreme rashness on the part of some when they want to make human abilities the measure of what nature can do. On the contrary, there is not a single effect in nature, even the least that exists, such that the most ingenious theorists can arrive at a complete understanding of it. This vain presumption of understanding everything can have no other basis than never understanding anything. For anyone who had experienced just once the perfect understanding of one single thing, and had truly tasted how knowledge is accomplished, would recognize that of the infinity of other truths he understands nothing.

The expression of these kindly feelings were not restricted to a section of the country, nor to a division of the people. They came from individual citizens of all nationalities; from all denominations — the Protestant, the Catholic, and the Jew; and from the various societies of the land — scientific, educational, religious or otherwise. Politics did not enter into the matter at all.
I am not egotist enough to suppose all this significance should be given because I was the object of it. But the war between the States was a very bloody and a very costly war. One side or the other had to yield principles they deemed dearer than life before it could be brought to an end. I commanded the whole of the mighty host engaged on the victorious side. I was, no matter whether deservedly so or not, a representative of that side of the controversy. It is a significant and gratifying fact that Confederates should have joined heartily in this spontaneous move. I hope the good feeling inaugurated may continue to the end.

Conclusion
1880s, Personal Memoirs of General U. S. Grant (1885)

1980s, First term of office (1981–1985), Abortion and the Conscience of the Nation (1983)

Preface, p. ix
The Pig Who Sang to the Moon (2003)

Address to the United Nations (1964)

The trial of Charles B. Reynolds for blasphemy (1887)
Context: I want you to understand what has been done in the world to force men to think alike. It seems to me that if there is some infinite being who wants us to think alike he would have made us alike. Why did he not do so? Why did he make your brain so that you could not by any possibility be a Methodist? Why did he make yours so that you could not be a Catholic? And why did he make the brain of another so that he is an unbeliever — why the brain of another so that he became a Mohammedan — if he wanted us all to believe alike?
After all, maybe Nature is good enough and grand enough and broad enough to give us the diversity born of liberty. Maybe, after all, it would not be best for us all to be just the same. What a stupid world, if everybody said yes to everything that everybody else might say.
The most important thing in this world is liberty. More important than food or clothes — more important than gold or houses or lands — more important than art or science — more important than all religions, is the liberty of man.