The question often comes up just how do seers see? There are at least two different types of seers with respect to perceiving activity in the spirit realm, and how they perceive things in the spirit differ.
How do Seers see who see very clearly?
For some seers, something is literally hitting their retina and their optic nerves are literally transferring this information to part of their brain, which literally interprets it visually. They see very clearly things in the spirit realm. There is some brain chemistry activity going on related to this very clear ability to see things.
Biochemical reactions are at play.
When seers take certain antidepressants or anti-migraine drugs, the brain chemistry changes in such a way that sometimes the seer ability is shut completely off. And yet, when these same people abstain from these medications, about two weeks later, the seer ability appears to switch back on.
I suspect the brain chemistry related to pineal gland in these types of seers that differ from non-seers, allowing their brains to interpret quantum wave patterns triggered by activity in the spirit realm that are reaching their retinas.
It’s like having a special antennae up that somehow pics up quantum vibrations that are emitted by spiritual activity.
How do Seers see who see less clearly?
For other types of seers, their brains are picking up some sort of impression from the spirit realm, which it interprets visually, but the activity is probably not hitting their retinas, or at least not as clearly as the above type.
The impressions in the brain may come in a waking state or in a sleeping state (in which case, the impressions are dreams). They are able to perceive things physically, without some sort of lightwaves hitting their retinas, or if something does hit their retinas, it’s very faint, but their brains are still able to tune in to it, sometimes with practice, to detect the impression isn’t natural.
The pineal gland probably plays a role for these types of seers as well.
The Pineal Gland
Possibly, the pineal gland in seers has special qualities which enable them to see aspects of the spirit world that are present in our reality. However, research needs to be done to examine just what enables seers to see into the spirit realm.
Most seers of the first kind cannot control this sight: it comes and goes. Seers of the second type can tune in or out, but also cannot perceive as clearly.