The growth of Knowledge consists of correcting misconceptions in our theories. Ever since the Enlightenment this had happened through a tradition of criticism. New explanations are proposed, criticized, and then refined. Since the tradition of Conjecture and criticism has created all Knowledge and Progress it's absolutely imperative that we keep it. Free speech is critical. No idea should be beyond criticism.

We have made virtually no progress over the vast majority of human history. Our species has existed for 200,000 years and for the vast majority of that time, people were alive, they were thinking, they were suffering, and they wanted things. But nothing ever improved. The improvements that did happen happened so slowly that archaeologists can’t distinguish between artifacts from eras separated by thousands of years. Then there was slow improvement, and then faster improvement. Then there were attempts to institutionalize a tradition of Criticism, which is the key to rapid progress—that is, progress discernible in a human lifetime—and there was also Error Correction, so that regression was less likely. That happened several times and failed every time except once—in the European Enlightenment of the seventeenth and eighteenth centuries.