Apart from “the spirit of a person”, which is a description of what or who that person is, spirits are basically thought patterns that become mainstream, or obsessive, although even strong memories can be classed as “spirits”.
“I say you are gods” appears in the old testament. Humans were made in the image of God, and as such, have latent power at their disposal. We are “spiritual” beings, because all of the creation has a connective influence on every other part of it.
Our thinking is a part of it all, as God is intimately connected to his creation, knowing the fall of every sparrow, and every hair on our head.
When thought patterns become “locked in” to certain habits or obsessions or suchlike; they have a spiritual influence.
Large amounts of superstition exist because of people observing “happenings” that they then attach to what appears to be the obvious cause.
People see ghosts, because of the spiritual influence existing, possibly through the distortion of the latent power of God, or more correctly, as that power in humans they have as “copies” of the divine.
When we come to biblical times, and particularly perhaps through Greek superstitious influence, we find the cause of all manner of sicknesses being allocated to spirits.
There was a woman who had “a spirit of infirmity”. This seems a bit different, being fairly remote from any idea of mental aberration, and would seem to be one of those ailments that might have been more obviously attributed to curvature of the spine, a short leg, or something.
Others had blindness etc. (some of these have spiritual meanings also).
The “demoniacs” were those who were really in trouble. These were those who were “permanently” mentally affected. Also were descriptions of epileptics.
All these complaints were said to be caused by spirits and of supernatural origins.
There is the possibility that some saw them as “life forces”, as in having a submissive spirit for example, but predominately the superstitious notion would prevail.
The Spirit of God, is the life force of God, his essence, his life. But some of these other spirits were not life promoting, but instead, were life denying, even destructive.
Those who had a “gift” of psychic discernment, who perhaps operated as fortune tellers or similar, were those who were misusing the natural creative force. Apart from a one to one type of operation, there is also a kind of “universal consciousness” sort of thing, similar to the “cloud” in internet terms today, where information is pooled and stored.
By this means, information that we might consider unknowable and inaccessible, so that the telling of it is ascribed to some supernatural entity (such as the dead), is accepted as the only explanation. The “Rosicrucians” say that “thoughts have wings”.
Integrity difficulties arise when, for example, people pray to dead people, which is contrary to God’s intention.
It may be that every theological error directly impacts on a spiritual level, as well as the obvious surface repercussions.
There are many commonly accepted forms of “The supernatural”. But mostly, people are not willing to recognise that God himself is “THE Supernatural”, and it is to him they should be referring all things, and not to some supposed “dead person”, or to some imagined deity.
“Sowing seed” as in “sowing the word”, is the equivalent of “putting thoughts into someone’s head”. Jesus said “My words to you are spirit and life”. This means that his audible words received by the brain [heart] are transferred into thoughts that represent his spirit, and may become a representation of his spirit and so present life to the hearer.
Catholics take it a bit further with their transubstantiation of the bread and wine. This is when it gets to be superstition because they believe it supernaturally actually becomes the body and blood of Jesus.
“…for the word of God is living and active..….”