'Nobody else is having your experience for you'
The soul is the immaterial part of a person. It's the "I" in the statement "I am." As such, that sense of self is timeless, because God says that He put eternity in our hearts yet not that we would know the end from the beginning. However, we exist in a sequence of time, such that we can never have the same moment over again. Thus, our sense of being is obtained in the stream of experience. My colleagues in the world of Gestalt therapy understand this when they affirm that you can never step into the same river twice.
Our sense of being alive as a soul is an experience of self. It's the experience of being, and it comes, as primary experience, through being created in the image of God, who told Moses that His essential nature was existence itself. He said, "I am that I am."
The primary experience of being a soul is that I am; everything else in the stream of experience is derived and contingent as a result of being a soul among other souls in this or that context of life.
When I am focused on the experience of being myself, I put out of focus aspects of the world in which I exist. In actuality I cannot exist without others and without a supportive environment, but that is not my focus when I become introspective. When I focus on others and the environment, then I tend to lose the sense of self, because it is as if my soul becomes identified with whatever has my attention. Sometimes I can play tricks on myself, imagining that someone else is thinking or feeling this way or that about me, but at that time my focus is really on myself, and I have lost contact with the other. The experience of such "self-conscious" emotions as shame, guilt, embarrassment, and pride are examples.
Many people have believed that the soul inhabits the body, resulting in what has become known as dualism; however, dualism has fallen out of favour, and that's happened for many reasons. One of the reasons psychologists find it difficult to maintain a dualistic perspective when considering human beings is the mind-body problem. The mind is seen as essentially the same thing as the soul, or at least the name for a major feature of the soul. At any rate, after people realised that our organ of thought is the brain, they began to wonder if the mind was nothing more than what the brain does, making mind and brain synonymous.
Are they? Not quite, but that's a subject for another time.
Right now, I want to call your attention to something called "insight."
Some people have the ability to see themselves in context and to grasp what part they, themselves, play in their circumstances. That, to me, is a gift of grace. You have to be able to focus on your circumstances, holding those observations in one hand, while focusing on yourself and holding those observations in the other. Then, you have to be able to compare the two, asking in what ways one might influence the other.
Who does that? People with some kind of mastery do that. People who explored as babies do that. People who have an internal locus of control do that. People who are successful in life do that. People don't do that if they only see the world as a fateful place in which good or bad luck happens to people.
People don't do that if they've had everything handed to them, if they've never had to struggle so as to learn that they have a say in the circumstances of their lives, that there is a relationship between what they feel, think, and value "in here" and what kind of life comes to them in the world "out there."
Insight is the realisation that the "I" in "I am" is responsible for one's stream of experience.
Nobody else is having your experience for you, or merely putting it into your body. It's yours and largely a result of what you make it. Therefore, insight is you taking responsibility for yourself. It's one of the byproducts of psychotherapy, or in another vein, of spiritual growth, and it's a benchmark of maturity.