“The idea of free and unfettered science, unfettered by hypotheses, could only occur in the age of Liberalism. It is absurd.”

Possibly a paraphrase of Bertrand Russell in My Philosophical Development (1959): "This is one of those views which are so absurd that only very learned men could possibly adopt them." It is similar in meaning to Orwell's line from Notes on Nationalism (1945): "One has to belong to the intelligentsia to believe things like that: no ordinary man could be such a fool." However, Russell was commenting not on politics, as Orwell was, but on some philosophers and their ideas about language.
Misattributed
Variant: Some ideas are so stupid that only intellectuals believe them.

The Scientist As Rebel (2006)

Preface
What the Bones Tell Us (1997)

Amusing Ourselves to Death: Public Discourse in the Age of Show Business (1985)
Context: In the Middle Ages, there was a scarcity of information but its very scarcity made it both important and usable. This began to change, as everyone knows, in the late 15th century when a goldsmith named Gutenberg, from Mainz, converted an old wine press into a printing machine, and in so doing, created what we now call an information explosion.... Nothing could be more misleading than the idea that computer technology introduced the age of information. The printing press began that age, and we have not been free of it since.

Source: The Characteristics of the Present Age (1806), p. 11

Source: A Princess of Mars (1917), Chapter 9

Mont Saint Michel and Chartres (1904)
Context: Experience proved that man's power of choice in action was very far from absolute, and logic seemed to require that every choice should have some predetermining cause which decided the will to act. Science affirmed that choice was not free,— could not be free,— without abandoning the unity of force and the foundation of law. Society insisted that its choice must be left free, whatever became of science or unity. Saint Thomas was required to illustrate the theory of liberum arbitrium by choosing a path through these difficulies, where path there was obviously none.

33 min 20 sec
Source: Cosmos: A Personal Voyage (1990 Update), Heaven and Hell [Episode 4]
Context: There are many hypotheses in science that are wrong. That's perfectly alright; it's the aperture to finding out what's right. Science is a self-correcting process. To be accepted, new ideas must survive the most rigorous standards of evidence and scrutiny.
Context: There are many hypotheses in science that are wrong. That's perfectly alright; it's the aperture to finding out what's right. Science is a self-correcting process. To be accepted, new ideas must survive the most rigorous standards of evidence and scrutiny. The worst aspect of the Velikovsky affair is not that many of his ideas were wrong or silly or in gross contradiction to the facts; rather, the worst aspect is that some scientists attempted to suppress Velikovsky's ideas. The suppression of uncomfortable ideas may be common in religion or in politics, but it is not the path to knowledge and there is no place for it in the endeavor of science. We do not know beforehand where fundamental insights will arise from about our mysterious and lovely solar system, and the history of our study of the solar system shows clearly that accepted and conventional ideas are often wrong and that fundamental insights can arise from the most unexpected sources.

"Science and Dictatorship," in Dictatorship on Its Trial, by Eminent Leaders of Modern Thought (1930) - later as Dictatorship on Trial (1931), Otto Forst de Battaglia (1889-1965), ed., Huntley Paterson, trans., introduction by Winston Churchill, George G. Harrap & Co., (Reprinted 1977, Beaufort Books Inc., p. 107. https://books.google.com/books?id=IjsiAAAAMAAJ&dq=9780836916072&focus=searchwithinvolume&q=%22only+in+an+atmosphere+of+free+speech%22 https://books.google.com/books?id=alq9M3_8qIcC&dq=9780836916072&hl=en&sa=X&ved=0ahUKEwj9w8nJkYfKAhUL12MKHf5uCscQ6AEIHDAA http://babel.hathitrust.org/cgi/pt/search?q1=%22Science%20can%20flourish%20only%20in%20an%20atmosphere%20of%20free%20speech%22;id=uc1.%24b47955;view=1up;seq=9;start=1;sz=10;page=search;orient=0 http://catalog.hathitrust.org/Record/000590821
1930s
Context: A dictatorship means muzzles all round and consequently stultification. Science can flourish only in an atmosphere of free speech.