The more we progress the more we tend to progress. We advance not in arithmetical but in geometrical progression. We draw compound interest on the whole capital of knowledge and virtue which has been accumulated since the dawning of time.
In an article on Bunyan lately published in the "Contemporary Review" - the only article on the subject worth reading on the subject I ever saw (yes, thank you, I am familiar with Macaulay's patronizing prattle about "The Pilgrim's Progress") etc.
All censorships exist to prevent anyone from challenging current conceptions and existing institutions. All progress is initiated by challenging current conceptions, and executed by supplanting existing institutions. Consequently, the first condition of progress is the removal of censorship.