This essay offers a detailed reconstruction of the thought of Inayatullah Khan al-Mashriqi, a camp-follower of fascism in inter-war India who sought to reformulate Islam as a “Religion of Science” according to the precepts of Darwinian evolutionism. Mashriqi has so far been neglected because his political impact was only short-term and did not contribute to the larger story of decolonization in India and Pakistan. But far from being marginal, Mashriqi's philosophical ruminations actually provide a window for a much-needed re-evaluation of the meaning of colonial modernity. While there was much in Mashriqi's writing that conforms to the usual picture of anti-colonial nation-building—his obsession with the truth of science, for instance, and his emphasis on disciplinary political methodologies—the by now standardized critique of such features in the “postcolonial” literature no longer suffices. Behind a façade of continuities with nineteenth-century “Enlightenment” traditions stood a much darker vision of modernity that no longer had any recourse to the certainties of a grand narrative of modernization. Instead, it was a vision that fluctuated between mystical exuberance and deep pessimism. The only sense of certainty was provided by a radical notion of emotional authenticity and a related belief in quasi-religious leadership figures. The larger conclusion to be drawn from the dualistic and contradictory structure of Mashriqi's “fascism” is that the intellectual history of inter-war South Asia needs to be given relative autonomy from the standard nationalism–modernization narrative, for rather than the continuation of an earlier modernity, it should be interpreted as the starting point of a new and much darker formation that arguably continues into the present.