Sir Karl Popper’s (2002) method of historicism has been neglected in the analysis of the radicalisation of Afghanistan’s society in the form of the Taliban. Popper’s historicism is the idea that the past may allow the forecasting of the future by understanding the state of the present in one specific line of historical inquiry. It is argued herein that by analysing periods of imperialism—those eras of social injustice, violence and oppression—it is seen that such imperialism led to radical fundamentalism, as many had no choice but to lash out. The push to strenuous religious identity, heavily laden with violent tactics, was the natural response of peoples trying to maintain their identities and collective destiny from imperial domination. Furthermore, as evidence continues to show, most often those individuals that are first to radicalise are the poorest of the poor, the dispossessed, or those who have experienced violent injustices. Using Popper’s method, it is possible to explain how imperialism breeds radicalism (using Afghanistan as an example) and as such provide some general recommendations to swing the pendulum in reverse so as to minimise radical behaviour. This article has implications for international relations, foreign policies and aid.