Towards a fruitful concept of radicalisation: a synthesis.

The term 'radicalisation' is relatively new. It is mostly the result of the political climate since 2005, but now widely used in work on extremism, fundamentalism, conspiracism, fanaticism, terrorism, and counter-terrorism. But exactly what is radicalisation and can we still properly use the term in the face of the many objections that have been levelled against it? I defend a conception of radicalisation that combines the fourmain approaches in the literature, the so-called monist and pluralist, as well as the absolutist and relativist ones. It does so on the basis of conceptual analysis, reflective equilibrium and particular case studies. Since the term will not be going away, it is wiser to be as lucid on how one defines it as possible. Such a definition matters for three reasons: there is much confusion in the public debate about radicalisation, e.g. about Islamism, increasing right-wing radicalisation in Europe and North America, and the views of conspiracy thinkers and anti-vaxxers, the term 'radicalisation' is also widely used in the academic literature on terrorism and counter-terrorism, but there is much unclarity about its relation to violence, to phenomena like fundamentalism, extremism, terrorism, and, finally, in order to be fruitful in research we need a definition that can be operationalized.