Long ago I read a book that was very popular in its day; Johnathan Livingston Seagull. The author, Richard Bach, used the story of one bird, Johnathan, to illustrate that what may seem impossible can be attained with the correct mix of courage, common sense and resolve.  The story struck a nerve for many, myself included, and is no doubt the initial motivation for a great many endeavors by human beings.
Mr. Bach wrote another book following the success of Seagull, J. L. The book is Illusions. As the title suggests, what we see can be misleading. A few pages still ring strongly in me from thirty plus years ago when I read the book. It plays like a movie reel in my mind; a man floundered on what we view as land, and could only gain firm purchase and equilibrium by climbing out of the splashing, wavy mess of rock and dirt and grass. To do so, he had to pull himself up and onto a surface of water.
A close comparison can be found in the movie the The Matrix, when Morpheus and Neo are sparring in a dojo, or martial arts training room. They are in a training program. Their physical bodies are reclined in chairs as they are plugged into the matrix.  Neo is getting whipped and whipped good. He breathes rapidly. Morpheus asks Neo, “Do you think that is air you are breathing?”
Our reality is defined by our visible portion of the electromagnetic spectrum, or EMS. And what a tiny sliver it is! Of the ‘to date’ known EMS of 100%, human beings experience a mere .0035%.  If we consider one twenty-four hour day as the full 100%, at our visible portion of .0035%, we would be ‘awake’, or ‘aware’, for only five minutes out of the 1440 minutes a full day is comprised of.
99.996% is a stunning figure when we apply that to the ‘unknown’. Of course, technology allows us to see beyond our sliver into the larger balance, but for those of us relying on two eyeballs, a nose, a couple of ears, our touch and taste, it would seem we are wandering in a vast cavern in the dark, with a single match as our only source of light.
Knowing as we do that there exists almost 100 times more planes of existence than we perceive has helped me in believing in a higher power. It seems to me that a person must be myopic, or very shortsighted, to proclaim there is no God, no alien life forms, no other entities beyond those our sliver of perception reveal to us.
If we fill a container of water, allowing both the water and the glass container are, to our naked eye, crystal clear, we could conclude the water is composed of nothing beyond two parts hydrogen and one part oxygen. But, if we place a drop of this water beneath a slide to view through a microscope, we would see the ‘crystal clear’ water is anything but. It is teeming with life, filled with particulates of both organic and inorganic matter. What we see is not always as it appears.
Science has proven beyond doubt that all matter is in motion, so when we hold a rock in our hand, what we are really holding is a mass of atoms whirling at inconceivable speeds, but doing so in a pattern that results in what we call a rock. If that rock is tossed into a stream of lava, the pattern dissolves and the rock loses the structure of that which allows us to call it a rock, even as the same components still exist, though now in a liquefied form which we call lava.
With so little about our world known, and so much of it unknown, an open mind is not only a benefit to our growth, it is a necessity. Perhaps a ghost is simply an entity existing on a different frequency of the electromagnetic spectrum. Kind of takes the ‘spooky’ out of the equation.
As humans, we perceive .0035% of the EMS. Maybe a giraffe experiences .00035%. Who knows? Perhaps it is not so far fetched to posit that God experiences, or has a back stage pass if you will, to the full 100% of the electromagnetic spectrum. One thing is certain; if something cannot be proven one way or the other, then both options are equally feasible.