Abstract

Public opinion is a central concept in political sociology, since it represents the main informal route to democratic legitimacy, both through the social processes of consensus building, and the exercise of a critical function - of an informal but politically influential counter-power. Various competing perspectives on the concept of public opinion have successively emerged since the eighteenth century. However, none of these were discarded once for all, or, conversely, supplanted the others. In the categorisation proposed in this paper, these concurrent perspectives define public opinion, respectively, as: (a) Social court, (b) Public discussion, (c) Collective action, (d) Majority opinion, (e) Public emotion, (f) Multidimensional process. In order to disentangle this enduring theoretical ambiguity, the second part of this article presents a typology of the main contemporary forms of expression of public opinion: (1) Collective attitude, (2) Aggregate opinion, (3) Current of opinion, (4) Movement of opinion. Each of these theoretical and research-oriented types of public opinion combines different elements of the previous perspectives, and identifies various processes that tend to coexist in the contemporary public sphere. Each type is defined on the basis of a different combination of the following criteria: stages of public thematisation; levels of «processuality»; types of publics involved; principles of effectiveness; political function; related theoretical concepts; main research instruments and techniques. An inclusive definition for the four types will complete this attempt at a sociological re-conceptualization of the contemporary forms of public opinion.