The theory of the Habermasian public sphere is applied to Twitter. To do so, the traditional literature on public opinion is combined with more recent literature on social media. After the literature research the main knowledge gap is identified. This gap is the lacking relation between the philosophical investigation on public opinion on Twitter and an empirical investigation on actual tweets. This thesis combines the fields of philosophy and data science to contribute to the knowledge gap. Palm oil is used as a case study. The main research question is: How can public opinion on Twitter be characterized, on the case study of palm oil? The findings of this research suggest how Twitter, in its current form, does not create the optimal environment for forming something that is approaching public opinion due to five characteristics: the exclusion of more than half the world population (a), the domination by a few users (b1) (often with strategic interest (b2)) , the pollution through spam (c), Twitter’s role (d) and the characteristics of tweets (e). a. The exclusion of more than half the world population from social media is at least based on the lack of internet access, new media literacy and cultural capital. b.1. The dominating key players are users who get the most attention from other users, policymakers and journalists. This can either be on a specific topic, or transcending topics. The findings from this research suggest that organizations like Greenpeace, BBC Earth and the Roundtable on Sustainable Palm Oil have an above average role in guiding the thinking of the public and therewith steering public opinion. It is difficult to find a user that is saying something completely different than what the defined influencers are saying. These few key players play an above average role in defining public opinion on Twitter, and the influence of this role is not limited to Twitter. b.2. The tweets analyzed show how the dominant key players often act with a strategic interest in mind. The public sphere should, according to Habermas, be free of power and ideology and the only common interest should be the interest in good opinion formation. c. The pollution through spam is argued to play a serious role in influencing public opinion on Twitter. The exact effects of fake accounts and hyperactive automated users is unclear but it can be argued, as can be seen from the examples, that they cause a stream of misinformation and therewith influence public opinion. d. It cannot be proved what Twitter is doing, and if and how they have influenced the debate on palm oil, since the algorithm is nontransparent. Examples like Morozov’s accusation of censorship in Twitter’s ‘trending algorithm’ shows the influence they can have e. tweets are not just 280 characters. They are often carefully considered combinations of hashtags, calls for action, snippets of information, interpreted data and images or videos. These characteristics all help in convincing the reader of the point the user is trying to make.