The Dutch rationalist philosopher Benedict de Spinoza (1632-1677) thought that the right of the individual to the free expression of his or her ideas was an “indefeasible natural right” much like the right to property:
Since, therefore, no one can abdicate his freedom of judgment and feeling; since every man is by indefeasible natural right the master of his own thoughts, it follows that men thinking in diverse and contradictory fashions, cannot, without disastrous results, be compelled to speak only according to the dictates of the supreme power. …
(T)he object of government is not to change men from rational beings into beasts or puppets, but to enable them to develope their minds and bodies in security, and to employ their reason unshackled; neither showing hatred, anger, or deceit, nor watched with the eyes of jealousy and injustice. In fact, the true aim of government is liberty.
About this Quotation:
When Spinoza wrote these words (1670) in defense of freedom of expression it was a dangerous thing to do even in a relatively free state like the Netherlands. As was often the practice at that time he offered both theoretical as well as practical reasons for this. The theoretical ground was a strong one, namely that the right to hold thoughts in one’s own mind and to express them to others via speech or print was an “indefeasible natural right” much like the “inalienable rights” expressed in the American Declaration of Independence penned 100 years later. Like other natural rights this right was not negotiable - all people had this right from the fact of being a human being with a given nature. Even Kings (or especially Kings) had to respect this right and this is one reason why they thought Spinoza’s position was a threat to their power. His weaker argument was a prudential one, that it might be in the interests of those who wielded religious or political power to grant some free exercise of thinking, speaking (or preaching, which is just another form of speaking), and printing, because it prevented speech from being driven underground where it might morph into even more virulent, anti-state and anti-church forms. Furthermore Spinoza argued, censorship did not work for long because men just learned to think one thing and say another, and also figured out ways to get around the oppressive laws. Eventually the Netherlands became a haven for heretical religious and political thinkers in England (e.g. John Locke) and France (Voltaire) who printed books in the Netherlands which were banned in their own countries, thus creating a nice new source of income for the Dutch printing industry. A “good government” soon learned that if it wanted to promote “progress in science and the liberal arts” it might also have to allow some freedom in less savoury matters such as individual criticism of the privileged church or of the Sovereign.