Overton Window
==============

The Overton Window is the range of ideas tolerated in public discourse. Joseph
Overton described the window, including a range of how an idea is accepted,
particularly in the political sphere:

    Unthinkable
    Radical
   |Acceptable
   |Sensible
   |Popular
   |Policy
   |Popular
   |Sensible
   |Acceptable
    Radical
    Unthinkable

Overton described a range from more to less freedom.

Similar work by Hallin described three spheres of media coverage: sphere of
consensus, sphere of legitimate controversy and sphere of deviance.