““I was trained in the old tradition! We found our strength in the basic verities, to which you, as a patrician, must surely subscribe. Am I right in this?”
“Absolutely, and in all respects!” declared Cugel. “Recognizing, of course, that these fundamental verities vary from region to region, and even from person to person.””

Letter to Evert Augustus Duyckinck (3 March 1849); published in The Letters of Herman Melville (1960) edited by Merrell R. Davis and William H. Gilman, p. 79
Context: And do not think, my boy, that because I, impulsively broke forth in jubillations over Shakspeare, that, therefore, I am of the number of the snobs who burn their tuns of rancid fat at his shrine. No, I would stand afar off & alone, & burn some pure Palm oil, the product of some overtopping trunk. — I would to God Shakspeare had lived later, & promenaded in Broadway. Not that I might have had the pleasure of leaving my card for him at the Astor, or made merry with him over a bowl of the fine Duyckinck punch; but that the muzzle which all men wore on their soul in the Elizebethan day, might not have intercepted Shakspers full articulations. For I hold it a verity, that even Shakspeare, was not a frank man to the uttermost. And, indeed, who in this intolerant universe is, or can be? But the Declaration of Independence makes a difference.—There, I have driven my horse so hard that I have made my inn before sundown.

2014, Young Southeast Asian Leaders Initiative Town Hall Speech (November 2014)

Conference call https://www.nytimes.com/cq/2007/01/31/cq_2212.html?pagewanted=all with reporters after announcing candidacy for the 2008 Democratic president nomination (January 30, 2007)
2000s

Speculating on the nature of radioactive emanations, in his Nobel lecture http://nobelprize.org/nobel_prizes/chemistry/laureates/1904/ramsay-lecture.html, December 12, 1904.

As quoted in Edmund J. Keller (1991) Revolutionary Ethiopia: From Empire to People's Republic, Indiana University Press, p. 212

The Value of Science (1955)
Context: The scientist has a lot of experience with ignorance and doubt and uncertainty, and this experience is of very great importance, I think. When a scientist doesn’t know the answer to a problem, he is ignorant. When he has a hunch as to what the result is, he is uncertain. And when he is pretty darn sure of what the result is going to be, he is still in some doubt. We have found it of paramount importance that in order to progress we must recognize our ignorance and leave room for doubt. Scientific knowledge is a body of statements of varying degrees of certainty — some most unsure, some nearly sure, but none absolutely certain. Now, we scientists are used to this, and we take it for granted that it is perfectly consistent to be unsure, that it is possible to live and not know. But I don’t know whether everyone realizes this is true. Our freedom to doubt was born out of a struggle against authority in the early days of science. It was a very deep and strong struggle: permit us to question — to doubt — to not be sure. I think that it is important that we do not forget this struggle and thus perhaps lose what we have gained.

Election campaign launch, February 14, 1996.

Address to the European Parliament (2015)
Context: There are those living in Europe today who remember the ravages that struck the continent in the late 1930s and the World War that followed because of an aggressive, expansionist ideology based on hate and disregard for the very essence of humanity. Europe’s war became the World’s War. Today, we are fighting a similar war. A war against an expansionist ideology that feeds on hate; that is committing murder in the name of God and religion to justify evil actions that no religion tolerates — a war against terrorists who disrespect Islam’s values and humanity’s values.
Our victory now depends on our unity. Europe’s role is vital. Only by cooperation can our regions shut down the sources of terrorist support and defeat their purposes.
It is also essential that our regions renew the source of our great strength: the mutual respect that binds and sustains us. Young people, especially, must be inspired by values that reject violence, create peace and build inclusive society.

Source: The Autobiography of Malcolm X