Radicalisation has burgeoned into a multidisciplinary subfield of terrorism studies. Many recent publications describe it as a ‘process’, as in this typical definition: ‘radicalization can be loosely defined as a process where a previously passive individual changes to become more revolutionary, militant or extremist, and has been closely tied with those involved in terrorism’ (McGilloway, Ghosh and Bhui 2015: 39; see also Aistrope 2016: 182; Crone 2016; Demetriou and Bosi 2016; Hafez and Mullins 2015: 959; Leistedt 2016; Maskaliūnaitė 2015: 9; Neumann 2013: 874; Powers 2014: 2; Pruyt and Kwakkel 2014; Tsintsadze-Maass and Maass 2014). Radicalisation is a process of subjectivation, given that it indicates a transformation in thoughts, beliefs, opinions, behaviours or belongings. This subjective mutation consists in departing from a status quo to follow a path along a political continuum, with ‘moderate’ at one pole and ‘extremist’ at the other (Richards 2015). However, what counts as moderate or extreme ‘varies depending on what is seen as “mainstream” in any given society, section of society or period of time’ (Neumann 2013: 876–7). Otherwise stated, radicalisation is historically and contextually specific, and it ‘occurs in all societies and cultures, and arises in many types of movements, including ethno-nationalist, ideological, and non-Muslim religious ones’ (Hafez and Mullins 2015: 968).

As of the writing of this chapter in 2018, Islamic extremism had received the most attention in recent global mainstream media reports, because ‘right-wing extremist attacks are seen mostly as isolated events when compared with other attacks, such as those by Islamist extremist terrorists’, even though ‘statistics clearly show the significant risk posed by violent right-wing extremists in Western countries’ (Koehler 2016: 84, 86). While Euro-American far-right militancy and Islamic fundamentalist extremisms dominate headlines today, in the 1970s far-left radicalism stood out. Whether it refers to the far right, the far left or religious fundamentalism, the very idea of radicalisation defines extremes in relation to a sociopolitical centre. For the purposes of this chapter, I redefine radicalisation as a movement away from a centre, in any direction.

Radicalisation scholarship, by default, situates itself at the prevailing centre, the zero point from which extremes are perceived, defined and represented.