The category of belief has been severely criticised in the last decades but ideas of having principles based on interior refl ections and conscience are as strong as ever across the world. This indicates that the modern idea of conviction - religious or secular - should be understood as a way of relating to the world that has a genealogy of its won that is not identical to religious belief. Modern convictions are based on two forms of ethics: firstly an individualized ethics of sincerity that emerged from the 17th century onwards as an ideal of honest and consistent public conduct. Secondly, an ethics of consequence that emerges with radical, Jacobin and collective politics and a new belief in radical socio-political utopias in the 19th century. In the 20th century, these ethical formations have spread across the world and form today the basis of a global grammar of interiority that lies at the heart of near-universal fi gures such as the 'activist' and the committed selfl ess social worker.