Carl Sagan's COSMOS recalls the burning of Alexandria's library, the greatest of its time. More than a repository of scrolls, the library was a center of study and scholarship, what we would today call a university. Supposedly it contained a complete history of the ancient world, knowledge now lost. Among those who held the title of Head Librarian were Erastothenes, who in the 3rd century BC calculated Earth's circumference; and Aristarchus, who in the 2nd century BC suggested that Earth was not centre of the universe. Euclid and Archimedes also studied at the library,
In COSMOS we read about Hypatia, the last librarian of Alexandria and a woman famed in her time for mathematics. She was also a philosopher and astronomer. Alexandria's library was burned several times: by Julius Caesar's forces in 48 BC, by the Roman Emperor Aurelian in 270 AD, by the Coptic Pope Theophilus in 391 AD, and by Muslims in 642 AD. Hypatia was horribly murdered by a mob in 415 AD. (Sagan's book takes some liberties with history, linking her death with the burning of the library).
Has humanity advanced in these thousands of years? The historical record shows that burning of books can be a tactic of any philosophy. Today in our computer age we have censors trolling the internet and Arxiv deleting or attacking what does not agree with them. What has not changed is that we must always be vigilant against those who would burn books. Those who would burn books will also burn people.
From ancient times until this month some people will try to burn libraries. Erastothenes' spherical Earth, Aristarchus' cosmology, and the achievements of Hypatia outlived them by thousands of years. Discoveries about nature are truths that can not be censored. If the speed of light slows down or a Black Hole exists nearby, no human censorship can prevent it.