The contemporary German philosopher Jürgen Habermas has introduced a set of three concepts that I find useful. They play out in the 140-character messages, “tweets,” that populate Twitter. Here are Habermas’ three concepts, with tweets as illustrations. (I found these examples within seconds as I wrote this blog post.)

Lifeworld is the background of ordinary life: mainly private, maybe somewhat limited or biased, but also authentic and essential to our satisfaction as human beings. When in the Lifeworld, we mostly communicate with people we know and who share our daily experience, so our communications tend to be cryptic to outsiders and certainly not persuasive to people unlike us. Real examples from Twitter: “y 21st bday with my beloved fam, bf and bff :)” … “Getting blond highlights for new year.” … “Thanks! You too! I hope you get a chance to rest over the weekend before ‘life’ comes back at us.”

The Public Sphere is the set of forums and institutions in which diverse people come together to talk about common concerns. It includes civic associations, editorial pages of newspapers, New England Town Meetings, and parts of the Internet. The logic of public discourse demands that one give general reasons and explanations for one’s views–otherwise, they cannot be persuasive. Examples from Twitter: “Is it time to admit that the failures in our intelligence on terrorism are not systemic/technical but human/cultural?” “Clyburn Compares Health Care Battle To Struggle For Civil Rights” … “Reports from Iran of security forces massing in squares as new footage of protests is posted.” (Note that each of these tweets had an embedded link to some longer document.)

The “System” is composed of formal organizations such as governments, corporations, parties, unions, and courts. People in systems have official roles and must pursue pre-defined goals (albeit with ethical constraints on how they get there). For example, defense lawyers are supposed to defend their clients; corporate CEOs are supposed to maximize profit; comptrollers are supposed to reduce waste in their own organizations. You can see the “System” at work on Twitter if you follow Microsoft (“The Official Twitter of Microsoft Corporate Communications”), The White House, or NYTimes.

When well designed, Systems can be efficient, predictable, and fair. But they prevent participants from reasoning about what ought to be done, because officials have pre-defined goals. Thus it is dangerous for the System to “colonize” the public sphere and the Lifeworld. It is also dangerous for people to retreat entirely from the public sphere into the privacy of the Lifeworld. The Twitter Public Timeline shows this struggle play out in real time.