Theories abound about what dreams are. Scientists only have a very basic grasp: they know that when humans dream, certain perceptual areas of the brain light up with electrical activity. This knowledge doesn't really solve any mysteries for us.
I want to offer that what we experience as dreams are actually worlds similar to our waking world in some regards. How can that be? you might wonder. Our waking world is so firm and solid - there's the ground beneath our feet, the hours that drag out through the day while we're at work, our stable identities and our stable friends. Meanwhile, in dreams things shift and alter constantly.
Dreams Are Energy
It can be because our waking world, just like the worlds we experience in our dreams at night, is only energy interpreted by our minds and senses into a specific configuration that seems very stable. Both dreams and the waking world are just streams of energy. Though the energy of our waking world certainly appears quite stable compared to that of our dream worlds, it's actually not rock solid. Far from it - everything we experience as matter is made up of tiny particles moving very rapidly through space.
And consider this: do you remember exactly what you ate for breakfast two mornings ago? And don't your friends always recall stories about your exploits together rather differently than you do? And haven't you often perceived things in a certain way that you later learned to be false or incomplete? I ask these questions only to point out that there's many facets of our reality that are subject to shift. Memory is especially vulnerable, but even present-moment happenings can be experienced very differently by various subjects.
The Dream Body
Just as we have a physical body with physical senses, we also have a dreaming body with dream senses. The sense organs of the dreaming body correspond to the chakras, or energy centers, of the body. One of the reasons why the worlds we experience in our night-time dreams don't seem as stable as our waking world is that our dreaming senses are not as highly developed as our physical senses. Many of us have undergone a very thorough education in navigating the physical world via our physical senses (remember your parents telling you to always "look out" for dangerous things and to always "listen" to them? they were drawing attention to and training your senses as they did that) and a very poor or nonexistent education in navigating the dream world via our dream senses (did your parents or teachers ever give you dreaming advice other than suggesting that you have "sweet dreams"?) In many other cultures in other times, the cultivation of the dream senses and the navigation of the dream world was considered just as important (if not more so) than the cultivation of the physical senses and the navigation of the waking world.
How could navigation of dream worlds possibly be more important than navigation of waking worlds? Don't we need to know how to get around in the waking world in order to survive? Absolutely, yes. And in that sense the waking world has a fundamental importance. But our present society wrongly values the navigation of the waking world so much more highly than that of the dreaming world that we actually end up having a lopsided and less happy existence. "Man cannot live on bread alone" is an old proverb. It means that human beings are more-than-physical creatures who need more-than-physical nurturance. It's not enough to just survive. We need to flourish at the level of soul, of spirit. And the dreaming experience is so crucial because that experience is actually where the soul can find its nourishment.
If the human physical form is nourished by food, water, and oxygen, the human soul is nourished by the symbols given to us in our dreams. Just like we have to gather food and water and oxygen in order to survive, we have to gather and assimilate our dream symbols in order to flourish. This is something that goes almost entirely neglected in our society because the prevailing paradigm doesn't like to recognize that there's a vast source of power beyond any worldly or material power. The capitalist system that we dwell in masterfully controls material resources and material power. It has, however, no such monopoly on immaterial power. The only way that capitalism can perpetuate itself is by having its institutions teach us to deny, ignore, minimize and otherwise neglect the vast power of insight and creation that comes to us each night through our dreams.
By choosing to meditate, keep a dream journal and practice dream interpretation, we begin to cultivate our dream body and our dream senses. We grow closer to integrating the energy streams of dreams with the energy stream of our waking world. As we achieve that integration, life within our waking world becomes more intuitive and more in harmony with our deep being. This occurs because most of us mistake who we are: we think we're our waking egos, a little separate "I" with a personal history of grievances and desires, longings and fears. In a way, this is correct. We are our egos. But we are also much more. We are souls, and our waking ego is just one little part of the whole soul that we are. The work of being alive is to come to know ourselves as complete, integrated souls. As we do this work we shed our pettiness and selfishness and become aware of our connection to the larger forces at work in the universe.
As we become fully integrated (Keats liked to say "made") souls, we are more and more capable of working for the good of everyone rather than just for the good of our individual egos. We're of greater service to others; we generate less drama in our lives; we experience greater joy. We don't need to look to the external world for validation through status, power, physical gratification and material wealth. In short, we become free of the snares of greed that tie us into capitalism. Instead, we become the sovereigns of our own selves, capable of answering directly to the source of everything that exists.