When an initiate or Rune Master casts a Rune spell, the god is manifest in the mundane world – the caster experiences the god. This experience is greater than abstract belief or knowledge – it is consciously perceived and felt. When Vasana casts Lightning, she experiences Orlanth, she IS Vinga. Once the spell is cast, she is again Vasana, but she has had that instant of being the god manifest.
Few Gloranthans – even God Learners – have much of our post-modernism or could even comprehend it. They have experienced spiritual truths and can’t help but acknowledge them – as that is the basis of their magic.