This article evaluates the validity of "theories of change" of anti-polarisation and anti-radicalisation interventions. Assumptions of four dominant social policies are confronted with the literature. In addition, epistemological issues are discussed. Notions of "what works and why", do not equate to straightforward application. Also, the potential of the four policy approaches depends in great measure on their conceptualisation of "polarisation" or "radicalisation". A focus on interventions could be dismissed as naive, when no account is offered of wider sociopolitical factors fuelling radicalisation or ethnic tensions. The interaction between these two notions is a relevant topic for future research.