Bab 469: Chapter 236: Grandma Dragon_2

But on the other hand, just like in the history of human science, there are two things in the physical world that are the most difficult to observe: one is the planets floating in outer space, and the other is the microscopic particles in everything, which happen to stand at the "large" and "small" extremes—similarly, in the Far Realm, there are highly similar phenomena.

Evil Spirits that are too weak in power are like an insignificant breeze, whose traces are difficult to detect even after they've vanished; and contrastingly, entities known as "Ning Shen", because of their colossal volume and presence in another world, completely surpass the perception range of the human brain.

In short, it's "self-deception" — the human brain inherently has this function. If one forcibly tries to surpass this natural barrier, the likely outcome would be a burnt-out mind.