They exist in our perception because we are earth creatures.
Yet perception is always coloured by the position in which we are standing.
"Seth Speaks" is one of the volumes of higher teachings that tell us that the natural laws that govern our earth system are to some extent local and do not apply everywhere.
The human ego is in development, slowly evolving into greater awareness, and one of the side effects of its independence is the unfortunate tendency for it to conclude that it is alone and disconnected from the Source.
We think we are the only life form in a vast Space full of dusty and fiery rocks.
If we cannot see it and measure it with our clever instruments then it does not exist.
This is embarrassingly naive and must cause great merriment among the higher beings.
Voltaire described this in one of his essays.
We live in a kind of bubble apparently sealed off by Time and Space.
Yet there are great similarities in the nature of both time and space that we don't seem to grasp.
All that has ever happened in the "past" still exists and the past can be travelled through in a similar way as we travel through space.
Scientists still argue about time travel but using the inner senses we can do it.
Many people have described accidentally falling through "time warps" and seeing the past still happening.
Equally many people have seen "future" happenings before they occurred.
Someone saw Hamburg ablaze in World War II months before it actually occurred.
This is just a tiny glimpse of the possibilities once we are free of illusion.
The fascinating thing is that once you have accepted the possibility of time travel you can also become aware that Space is just as much an illusion as Time.
Seth says that our perception of the vastness of outer space is an illusion only seen from our particular perspective.
Think of being a tiny creature living in the sand on a beach: what does it perceive as the universe? A relatively small rock a few inches away must look immense.
The roar of the sea, if it can hear it, must be a great mystery and subject to a lot of speculation as to its nature.
In terms of Basic Reality therefore Space is not what it seems.
Other dimensions of existence exist "in the same space" without being aware of each other.
Our loved ones who have passed over are not separated from us by a vast distance.
They are not separated from us at all in those terms, but closer to us than we can imagine.
The outer universe is a mere projection of the true inner universe, like a film on a screen.
Plato knew this thousands of years ago when he described our perceptions as the shadow on the wall.
These things can only be understood by using our inner senses.
More and more people are awakening to this in spite of the loud protestations of the materialist scientists who say that our life is random and temporary.
The evidence for life being multidimensional is overwhelming.
Both religion and science have had a hand in distorting the true reality, but the evolutionofour consciousness is grinding forward and leaving the old perceptions exposed as nonsense.
If you are ready then it will dawn on you.