the act or faculty of perceiving, or apprehending by means of the senses or of the mind; cognition; understanding.
the state or quality of being real.
Perception is part of a reality. Perceiving means to have the data that is available to make sense of something perceived by our senses. The top of an iceberg is visible only above the water horizon. The limit for perception is the water horizon. If the individual did not know anything else, it would just perceive the iceberg as a floating island. But the reality is that the iceberg is almost triple the size under the water. If the information would had been available, the perception would had changed in regards to approaching closer to the iceberg.
is the house on fire? Do you call 911?
The house is not on fire. It is just the reflection of the sun setting among the trees.
Same is with perceiving God. We do not see everything that goes on about His awesome presence which is revealed in every DNA process, in every living creature, in every solar system. The more you enter in knowing God, the more the perception changes.
Understanding God means to embark into a scientific research of the material world and non material world.
You see many things, but you cannot tell what you see. Your ears are open, but you do not hear.