Unknown Possibilities Quotes
Although most listeners had to spend some time parsing this famous quote, it actually was not a new notion. See Copernicus in linked quotes.
Secretary of Defense Donald Rumsfeld over a century later paraphrased this notion in discussing the problem with information from the intelligence agencies.
This statement as with others like it offended the religious authorities of the time as they claimed that they—-The Bible---knew everything important just as fundamentalist Muslims claim today about the Koran. So statements of this kind were considered heresy by some and still are.