“If Shakespeare had never existed, he asked, would the world have differed much from what it is today? Does the progress of civilization depend upon great men? Is the lot of the average human being better now that in the time of the Pharaohs?”

Ch. 22 http://www.literature.org/authors/twain-mark/connecticut/chapter-22.html
A Connecticut Yankee in King Arthur's Court (1889)

1840s, Heroes and Hero-Worship (1840), The Hero as Prophet

Quoted in Harold Nicolson's diary entry (6 July 1936), quoted in Nigel Nicolson (ed.), Harold Nicolson: Diaries and Letters. 1930-1939 (London: Collins, 1966), p. 268.
Later life

2014, Young Southeast Asian Leaders Initiative Town Hall (April 2014)

Αs translated by William Smith, in The Popular Works of Johann Gottlieb Fichte (1889), Vol. I, Lecture IV, p. 188.
The Vocation of the Scholar (1794)
Context: Upon the progress of knowledge the whole progress of the human race is immediately dependent: he who retards that, hinders this also. And he who hinders this, —what character does he assume towards his age and posterity? Louder than with a thousand voices, by his actions he proclaims into the deafened ear of the world present and to come —"As long as I live at least, the men around me shall not become wiser or better; — for in their progress I too, notwithstanding all my efforts to the contrary, should be dragged forward in some direction; and this I detest I will not become more enlightened, — I will not become nobler. Darkness and perversion are my elements, and I will summon all my powers together that I may not be dislodged from them."

Opening lines
The Napoleon of Notting Hill (1904)
Context: The human race, to which so many of my readers belong, has been playing at children’s games from the beginning, and will probably do it till the end, which is a nuisance for the few people who grow up. And one of the games to which it is most attached is called “Keep to-morrow dark,” and which is also named (by the rustics in Shropshire, I have no doubt) “Cheat the Prophet.” The players listen very carefully and respectfully to all that the clever men have to say about what is to happen in the next generation. The players then wait until all the clever men are dead, and bury them nicely. They then go and do something else. That is all. For a race of simple tastes, however, it is great fun.
For human beings, being children, have the childish wilfulness and the childish secrecy. And they never have from the beginning of the world done what the wise men have seen to be inevitable.

" Is Macroeconomics Really Economics? http://blog.independent.org/2013/08/14/is-macroeconomics-really-economics/," The Beacon (Independent Institute, 14 August 2014).
Context: The world probably would have been much better off had macroeconomics never been devised. Although I have in mind Keynesian macroeconomics above all, I include other types of macro models as well. I even include, somewhat reluctantly, the whole quantity theory approach descended from David Hume to the Friedmanites, now known as monetarism. … In short, among its many other deficiencies, as spelled out by Mises and his followers, monetarism’s most fundamental flaw is identical to the most fundamental flaw of Keynesian, Post-Keynesian, New Classical, and other theories advanced by macroeconomists during the past seventy or eighty years: not only does the theory leave out critical variables, but it is too simple, being expressed in huge, all-encompassing aggregates that conceal the real economic action taking place within the economic order.

Source: 1930s, In Praise of Idleness and Other Essays (1935), Ch. 8: Western Civilisation

The Education of Henry Adams (1907)