Francois-Marie d'Arouet lived from 1694 to 1778. In philosophy, he is better known as Voltaire. The French philosopher was a writer, activist and political idealist who used the written word to help push vast scientific, political and social change. He broke no new ground in the whirlwind of ideas sweeping Europe in the Enlightenment, but his writing served to introduce and popularize the original thinking of philosophers like Newton and Locke -- and to make him a celebrated public figure.
Voltaire was very outspoken when it came to organized religion. He lived in a historical period called the Enlightenment, when church and state began to separate. While he never openly declared himself to be a non-believer, he advocated a religious perspective known as deism. Deism proposes that there is some kind of supernatural creator, but it is not associated with any mainstream religion. Open opposition to religion was a serious offense that landed Voltaire in jail and ultimately, exile.
According to the "Stanford Encyclopedia of Philosophy," Voltaire was a strong advocate of political reform. He declared his own independent stance, saying he belonged to the "party of humanity." Aside from religion, his other main target was extremism in any form, be it political or religious. Voltaire directed much of his social and political criticism at the monarchy and aristocracy, also challenging the judicial system as "irrational and brutal."
Although Voltaire was a deist, he still had a very naturalistic worldview. He had a deep regard for science and its importance in promoting rational thought over superstition. Since he still believed in a supernatural creator, he did not subscribe to the emerging idea that living organisms could spontaneously generate from non-living matter. Still, Voltaire felt that basing your beliefs on "empirical evidence" was the antidote to religiosity and the dangerous authority it can create.
Voltaire was a proponent of personal liberty and freedom of speech, making the famous statement, "I disagree with what you say, but I will defend to the death your right to say it." For Voltaire, rational human beings -- for the most part -- were capable of thinking for themselves and therefore did not need institutions thinking for them. At the same time, he pointed out that many people are incapable of such rational thought and must therefore turn to religion for personal guidance. Despite his apparent disdain for religion, Voltaire was a strong advocate for religious tolerance, stating that diverse, open religious beliefs are fine, "as long as they are not murderous."