There is some debate in the literature as to what the word 鈥榚xtreme鈥� means because determining what is extreme is a subjective exercise. For the purposes of this review, extremism is the rejection of other perspectives, when one鈥檚 own views are thought to be exclusive (Davies, 2009). However, it does not simply 鈥渞efer to a rejection of liberal values鈥� or anti-democratic views (Kundnani, 2015, p. 26). Nevertheless, there are two attributes that are important when talking about extremism: (1) the political beliefs of extremists are not widely shared even within their own societies; and (2) extremists lack the means or power to obtain their goals on their own. Both traits are important in understanding their choice of strategy (Lake, 2002, p. 18). That is why extremist violence is used as a 鈥渇orm of communication that interacts with other forms of social and political communication鈥� (Crelinsten, 2010, p. 77). Violent extremism there- fore is defined 鈥渁s those activities and beliefs which are used to advocate, engage in, prepare, or otherwise support ideologically-motivated violence to further socioeconomic and political objectives鈥� (Mirahmadi et al., 2015, p. 2). This leads to radicalisation when it forms a moral hierarchy, in which extreme positions are justified on moral grounds.