It was years ago that Babylon 5 tied psychic powers to Vorlon genetic manipulation and hinted they were connected somehow to "hyperspace." It was also years ago that Stargate SG-1 tied them to "major rewiring of the brain" and other dimensions etc.
Those were scientifically ludicrous explanations but the simple truth is that we, the audience (or most of us anyhow) want
to be able to suspend disbelief. The ficitional science may be risible but to a hopeful eye, it floats like a mirage of cool water and shady palms in a desert of dry fact.
Defiance at this late stage gives us aliens wtih the "Sight." It appears to be a gift from the gods, compensating the Irathients's lack of culture with supernatural abilities. Apparently being free from the stultifying civilization allows one to partake of the numinous. And that, it seems, is all there is to that.
They couldn't even throw us a bone.