Speaking Freely Through the Ages As long as there have been laws, there have been attempts to silence people.

• Author: Gulliver, Katrina
• Position: Free Speech: A History From Socrates to Social Media

MANY LANGUAGES HAVE in-built speech codes: There are levels of formality and informality in address, words that are not to be used in certain contexts, even forms of speech specific to men and women. European languages tend not to carry the levels of baroque distinction found elsewhere, but they still maintain formal and informal registers. English is distinctive in having essentially abandoned them; our you was once the formal/plural form of address {thee being the familiar).

But when we talk about freedom of speech, we usually mean legal restrictions backed up by the state. These too date back thousands of years. Ancient edicts offered strict instructions in who was allowed to say what and to whom. Around 2500 B.C., the Sumerian Code of Ur-Nammu declared that "if a slave woman curses someone acting with the authority of her mistress, they shall scour her mouth with one sila [0.85 liter] of salt." I'm guessing that she wasn't allowed to say that slavery sucked either.

With Free Speech: A History From Socrates to Social Media, Jacob Mchangama races through those thousands of years of intellectual and political history to show how distinctive-and how essential--the concept of free speech is. Mchangama, a Danish lawyer, has been an important voice for liberty over the last decade, particularly in the context of Islamic blasphemy claims in Europe. His book is an excellent guide for anyone who wants to know why free speech matters.

For much of European history, the speech being widely policed was heretical or treasonous. (Or both: The divine right of kings meant a fair amount of potential crossover.) As Mchangama shows, early universities were sites of information exchange as well as crackdowns on those people thought to be spreading dangerous views.

These were by necessity elite debates: Most people had no opportunity to read the controversial texts that scholarmonks were troubled over. That started to change with the arrival of the printing press, although that didn't mean your average reader suddenly got sucked into Thomas Aquinas. As Mchangama points out, the same printing presses that disseminated philosophical tracts "churned out a steady stream of virulent political and religious propaganda, hate speech, obscene cartoons, and treatises on witchcraft and alchemy."

We see this with every new form of communication. Barely five minutes after the invention of the photograph, someone was taking nudie pics. But the printing press opened doors...