Science that needs logical demonstration has failed to eliminate religious concepts. It is as if they have own validity that cannot be broken by scientific knowledge we trust the most at present. In this paper, I will attempt to establish a new cognitive theory to help explain the basis of belief in religious concepts. This form of cognition will be named simply unifying-induction or unifying-inductive cognition. As illustrations, I will consider some typical religious discourses involving concepts such as "all-in-one" or "one is everything." It is these typically religious discourses that science has not been able to easily sweep away by its logical scientific proofs. In the end, although we perhaps cannot know if the religious beings such as gods really exist or not, we may understand these concepts are very the creation of human cognition. It also has important implications for other disciplines such as robotics, developmental psychology, cognitive archaeology, the history of science, the study of religion and so on. (C) 2016 Elsevier B.V. All rights reserved.