Answer:
freedom of speech
Step-by-step explanation:
Throughout his life time, Voltaire has published a lot of books that teach the mass about the importance of freedom of speech (approximately, he produced around 70 collections of books and essays about this topic).
He believed, Freedom of speech allow positive communication to occurs between different groups in society.
It enables people with different social class, political background, and religion to come together and make their point understood by other groups. This will increase the overall tolerance within members in society.