One of the primary elements of the culture of the Enlightenment was the rise of the public sphere, a "realm of communication marked by new arenas of debate, more open and accessible forms of urban public space and sociability, and an explosion of print culture," in the late 17th century and 18th century. Elements of the public sphere included: it was egalitarian, it discussed the domain of "common concern," and argument was founded on reason. Habermas uses the term "common concern" to describe those areas of political/social knowledge and discussion that were previously the exclusive territory of the state and religious authorities, now open to critical examination by the public sphere. The values of this bourgeois public sphere included holding reason to be supreme, considering everything to be open to criticism (the public sphere is critical), and the opposition of secrecy of all sorts.
How was the public sphere defined?
realm of communication marked by new arenas of debate, more open and accessible forms of urban public space and sociability, and an explosion of print culture