Definition:

In rhetoric, the place where citizens exchange ideas, information, attitudes, and opinions.

Though the concept of the public sphere originated in the 18th century, German sociologist Jürgen Habermas is credited with popularizing the term in his book The Structural Transformation of the Public Sphere (1962; English translation, 1989). See Examples and Observations, below.

See also:

• Common Ground

• Communication and Communication Process
• Deliberative Rhetoric
• Discourse Analysis
• Rhetorical Situation

Examples and Observations:

• "The public sphere is . . . a metaphorical term used to describe the virtual space where people can interact. . . . The World Wide Web, for example, is not actually a web; cyberspace is not a space; and so with the public sphere. It's the virtual space where the citizens of a country exchange ideas and discuss issues, in order to reach agreement about 'matters of general interest' ([Jürgen] Habermas, 1997: 105). . . .
  
  "The public sphere is . . . a metaphor which keeps us focused on the distinction between individual, personal forms of representation--over which we have a large degree of control--and shared, consensual representations--which are never exactly what we would like to see precisely because they are shared (public). It's a liberal model which sees the individual human being as having an important input into the formation of the general will--as opposed to totalitarian or Marxist models, which see the state as ultimately powerful in deciding what people think."
  (Alan McKee, The Public Sphere: An Introduction. Cambridge Univ. Press, 2005)

• Habermas on the Public Sphere
  "By 'the public sphere' we mean first of all a realm of our social life in which something approaching public opinion can be formed. Access is guaranteed to all citizens. A portion of the public sphere comes into being in every conversation in which private individuals assemble to form a public body. They then behave neither like business or professional people transacting private affairs, nor like members of a constitutional order subject to the legal constraints of a state bureaucracy. Citizens behave as a public body when they confer in an unrestricted fashion--that is, with the guarantee of freedom of assembly and association and the freedom to express and publish their opinions--about matters of general interest. In a large public body this kind of communication requires specific means for transmitting information and influencing those who receive it. Today newspapers and magazines, radio and television are the media of the public sphere. We speak of the political public sphere in contrast, for instance, to the literary one, when public discussion deals with objects connected to the activity of the state. Although state authority is so to speak the executor of the political public sphere, it is not a part of it."
  (Jürgen Habermas, passage from Strukturwandel der Öffentlichkeit, 1962. Excerpt translated as "The Public Sphere" and published in New German Critique, 1974)
• Blogging and the Public Sphere
  "Blogging reverses a trend that had become increasingly worrying in an era dominated by mass media, namely the erosion of what the cultural critic Jurgen Habermas called 'the public sphere'--an area where citizens gather to generate opinions and attitudes that affirm or challenge the actions of the state. Mass media offered the illusion of diversity while narrowing the range of real choices available--the '600 channels and nothing on' syndrome. Blogging has revived--and begun to expand--the public sphere, and in the process may revitalise our democracies."
  (John Naughton, "Why Everyone's Invited to the Tenth Birthday Bash for Blogger." The Observer, Sep. 13, 2009)