“Goebbels belongs to a widespread type of revolutionary; he is the intellectual revolutionary, mentally alert, inventive in destructive ideas, and a master of inflammatory speech.”

The Promise of Space http://books.google.com/books?id=FWwhAAAAMAAJ&dq=The+Promise+of+Space&ei=ab0yR__TKZzuoAL_mf3RDw&ie=ISO-8859-1&pgis=1 (1968); This and similar statements attributed to Mahatma Gandhi and J. B. S. Haldane may ultimately be derived from a statement attibuted to Arthur Schopenhauer:
On Clarke's Laws
Context: Clarke's Law of Revolutionary Ideas: Every revolutionary idea — in science, politics, art, or whatever — seems to evoke three stages of reaction. They may be summed up by the phrases:(1) "It's completely impossible — don't waste my time";
(2) "It's possible, but it's not worth doing";
(3) "I said it was a good idea all along."

Source: Lamb: The Gospel According to Biff, Christ's Childhood Pal

Source: Understanding Capitalism: Competition, Command, and Change, 2005, p.82

But incorrect ideas among the people are quite a different matter. Will it do to ban such ideas and deny them any opportunity for expression? Certainly not. It is not only futile but very harmful to use crude methods in dealing with ideological questions among the people, with questions about man's mental world. You may ban the expression of wrong ideas, but the ideas will still be there. On the other hand, if correct ideas are pampered in hothouses and never exposed to the elements and immunized against disease, they will not win out against erroneous ones. Therefore, it is only by employing the method of discussion, criticism and reasoning that we can really foster correct ideas and overcome wrong ones, and that we can really settle issues.
" VIII. ON "LET A HUNDRED FLOWERS BLOSSOM LET A HUNDRED SCHOOLS OF THOUGHT CONTEND" AND "LONG-TERM COEXISTENCE AND MUTUAL SUPERVISION" "
On the Correct Handling of Contradictions Among the People

As quoted by the New York Times http://www.nytimes.com/2003/10/22/us/luis-a-ferre-dies-at-99-pushed-puerto-rican-statehood.html in an October 22, 2003 obituary.

Source: Books, Beyond Order (2021), p. 197

Source: A Gift From Earth (1968), Ch. 2 : The Sons Of Earth
Context: From the beginning there had been a revolutionary group. Its name had changed several times, and Matt had no idea what it was now. He had never known a revolutionary. He had no particular desire to be one. They accomplished nothing, except to fill the Hospital's organ banks. How could they, when the crew controlled every weapon and every watt of power on Mount Lookitthat? If this was a nest of rebels, then they had worked out a good cover. Many of the merrymakers had no hearing aids, and these seemed to be the ones who didn't know anyone here. Like Matt himself. In the midst of a reasonably genuine open-house brawl, certain people listened to voices only they could hear.

Tactics and Strategy of the Latin American Revolution (1962)
Context: The most submissive countries and consequently, the most cynical, talk about the threat of Cuban subversion, and they are right. The greatest threat of the Cuban revolution is its own example, its revolutionary ideas, the fact that the government has been able to increase the combativity of the people, led by a leader of world stature, to heights seldom equaled in history. Here is the electrifying example of a people prepared to suffer nuclear immolation so that its ashes may serve as a foundation for new societies. When an agreement was reached by which the atomic missiles were removed, without asking our people, we were not relieved or thankful for the truce; instead we denounced the move with our own voice. We have demonstrated our firm stand, our own position, our decision to fight, even if alone, against all dangers and against the atomic menace of Yankee imperialism.

Speech (18 October 1967) http://www.cuba.cu/gobierno/discursos/1967/esp/f181067e.html