This thesis aims to create a trinary of the concepts of religion, rationalism and superstitions in order to understand the manifestation of secularism in the socio-political life of a society, with special focus on India. The secularization thesis that anticipated the gradual relegation of religion into the private sphere with the flourishing of the values of modernity, especially reason, rationality and scientific temperament, was declared deficient (Stark 1999, Berger 1999) after the rise of religious violence all around the world. A post-secular (Habermas 2008, Caputo 2011) society was being imagined by devising harmonious and mutual tolerance between religious and secular values. This thesis argues that the binaries of religion and secularism do not evince homogenously throughout the world. The extent of their reciprocity differs contextually, and that their reciprocity nominally depends upon a third category, i.e. the conception of superstitions in that society. Religion as well as secularism consider superstitions as a ‘non-essential’ category that needs to be purged in order to render ‘true’ religion and pure secularism respectively. The perception of what constitutes superstitions is important to understand the limits of religion and secularism in a society. This thesis tries to understand the social and political role played by superstitions in India historically and argues that the need to include them as an important conceptual category increases with the rise of Hindu nationalist discourses in India. This thesis uses the trinary of superstitions, religion and rationalism in the activities of Hindu nationalists and rationalists of India to place the debate of secularism and post-secularism in perspective.