The existence of religion can be understood as a direct result of the emergence of language (i.e. human consciousness). This can be explained as follows.
On Halliday's model, with the emergence of language and the stratification of linguistic content into meaning and wording, a metaphorical relation between meaning and wording became possible. This has the effect of creating symbolic (Token-Value) relations at the level of meaning — meanings of meanings — thereby expanding the overall meaning potential of language.
The earliest deployments of metaphor were lexical, rather than grammatical, because words are the least abstract dimension of language. This created the rich mythic symbolism of the world's religions, including the personification of material phenomena as gods, which amounts to a reconstrual of the natural world as intersubjective.
But even the restrictions of lexical metaphor can yield profound intellectual insights. For example, in Hindu symbology, the Universe is reconstrued as a mental projection (dream) of the God Vishnu, and in Abrahamic symbology, as a verbal projection of the Creator (God said "Let there be light. …"). That is, in both traditions, 'the world' is reconstrued as meaning that is projected by the creator of meaning. In this symbology, the creator god represents language as meaning potential, and an individuation of the creator god, a soul, represents an individuation of meaning potential, the consciousness of an individual human.
A scientific approach to religion is to try to understand it; a religious approach to religion is to denounce it as an abomination. The symbology of religious traditions potentially provides rich insights into the evolution of human consciousness.