Is your body “you”?
It sure doesn’t feel that way, does it? Your body is “yours,” you inhabit it, but the real “you” is inside, thinking and feeling and aware. “You” don’t sense “yourself” as something physical.
This is something that has confounded scientists and philosophers for centuries. That feeling is universal, and it’s awfully hard to say it’s not true, but there’s no way to demonstrate it scientifically or to even define its functions in concrete terms philosophically. If you’re not physical, then what are you made of? How does the “you” affect the physical world? How do “you” even control your own body?
There are no good answers from the natural world, so people have jumped to the hazy idea that there is a spiritual reality which parallels and interacts with natural reality, and the real “you” is a spirit, made of spiritual material.
Swedenborg says that not only is this true, but that spiritual reality - what he calls the “spiritual world” - is actually more real than the physical world, and is actually the source of physical reality. In fact, he says that every detail of the natural world is a sort of projection of a detail of the spiritual world, and if we understand those relationships we can see the spiritual reality within natural things, much as we see lines and curves on paper and understand them as words.
Often, then, the word “spiritual” is used by Swedenborg and on this website as a sort of catchall for non-material reality, everything about heaven and hell and our deeper loves and thoughts, when those loves and thoughts extend beyond physical things.
But Swedenborg also divides spiritual reality into three layers, and (somewhat confusingly) uses “spiritual” to describe the middle of those three layers.
The inmost level of spiritual reality is referred to as “celestial,” and is marked by a pure love of the Lord, which flows forth directly as wisdom. This is the highest state humans can reach, and is the state of the highest heavens, where people live in complete innocence and harmony from the Lord’s love.
The outermost layer of spiritual reality is referred to as “natural,” and is marked by a love of doing the Lord’s will and a knowledge of what the Lord teaches. This level exists in all of us, and is where we put what we know and love into action, where everything becomes tangible. Those in the natural heaven live simply, loving to do what’s right and taking joy in understanding what’s right.
Between those two is the midde, or “spiritual,” layer of spiritual reality. It is marked by love of other people, and a love of exploring and understanding the things the Lord teaches, making it in a way the most intellectual of the three. Those in the spiritual heaven love to explore what is true for its own sake, and marry that to a love of those around them, a love of serving and being good to them.
(References: Arcana Coelestia 4286 ; Divine Love and Wisdom 174, 251; The Word 3 [1-3]; The Doctrine of Life for the New Jerusalem for the New Jerusalem 86; The New Jerusalem and its Heavenly Doctrine 48)