For or against Brexit? : Justifying oppositional arguments in online discussion

Introduction. This investigation examines argumentation about political issues occurring in online discussion groups. A case study was made by concentrating on debates about Brexit - the prospective withdrawal of the United Kingdom from the European Union. Method. Building on Toulmin’s model for argument patterns, it was examined how oppositional arguments about Brexit were grounded by drawing on facts and opinion-based evidence and how the evidence of information these types was justified. To this end, a sample of 40 discussion threads initiated before the 2016 Brexit referendum were downloaded from PoliticsForum - an online platform. Analysis. The data consisting of 1563 messages were scrutinized by means of descriptive statistical analysis and qualitative content analysis. The focus was placed on the latter method by analysing the ways in which the discussants justified the rebuttal of opposing arguments. Results. Oppositional arguments justifications were mainly based on the description of personal opinions and negative evaluation of opposing views. Analytic approaches to justification based on explanation and comparison were less popular. This preference is probably due to the lower cognitive effort required while simply describing the attributes of an entity or judging its positive or negative qualities by drawing on one’s beliefs and experiences. Conclusions. Argumentation occurring in online platforms will form an increasingly important part of political struggles. On the other hand, online debates on controversial issues such as Brexit tend to be broad rather than deep.