"The dark realm"
The human mind is arguably the greatest mystery of the known Universe. It's thoughts are generated by chemical reactions in the physical brain, but thoughts occupy no physical space. They are produced by environmental stimulus, retained memories, and individual will, and exist only in the imaginary realm of the mind, yet they drive most of the physical actions of the modern human body. Some human physical action is still driven by instinctual reactions to environmental stimulus, but as the human mind has evolved physical action is driven more by abstract thought than by instinctual reaction to physical stimulus.
Some thoughts "flow" in response to environmental stimulus. Other thoughts are chosen to continuously "loop" in the mind causing the individual to spend much of his/her precious time (life) projecting their consciousness into the isolated realm of the mind. This causes the consciousness of the individual to become separated from the physical universe that all living creatures share. The longer the consciousness chooses to remain in these "looping" thoughts the longer it remains separated from the physical universe. These "looping" thoughts are commonly referred to as obsession.
Obsession is driven by memories of real experiences, mental conditioning (mostly rooted in childhood), and will. Memories that commonly initiate obsessions are rooted in fear, guilt, shame, lust, desire, religion, love, anger, curiosity, ambition, power, etc. These obsessions are thoughts that the individual chooses to "entertain", believing that by doing so they will solve a problem that is causing them pain, find a way to obtain possessions they long for, obtain status and power in their respective cultures, or for many other reasons. The insidious characteristic of obsession is that it doesn't guarantee you will obtain the things you long for, and even if you do they seldom, if ever, bring the satisfaction that you desire.
Every human living in industrial civilization chooses to obsess, some more than others. Industrial civilization requires the individual to obsess in order to make a living and survive. Some tragic souls obsess to the point of psychosis when perception of the physical universe becomes completely lost, and only their imaginary world exists to them. Industrial civilization is the product of obsession. Almost all of the inventions we live with today came from minds that were obsessed with the design of their inventions. Other minds obsessed over how to become wealthy from the manufacture, and sale of these inventions. We are beginning to see the irreversible destruction these obsessions have brought upon the Living Earth. Mankind originally perceived these inventions as "good", but ultimately the technologies produced by obsession have completely destroyed the living balance that once sustained the Earth. Without obsession human culture would have never grown beyond small, ecologically balanced tribes.
How can one escape the deceptive trap of obsession?
As the "wolves" of thought keep crashing against the doors of your mind, turn away from them and turn your consciousness toward the miraculous Creation you were born into. Thoughts can't enter your mind unless you invite them in by choosing to focus on them. If possible, get your body into a peaceful location, and choose to focus on seeing, hearing, smelling, touching (feeling), and tasting the things around you. Remember that you are spending (investing) your precious, limited time (life energy), so decide how much time you will choose to spend alone in the darkness of the mind, and how much time you will choose to spend in the reality of the material world with all other living creatures. The more time you choose to focus your consciousness on the physical input your body is constantly receiving the more peace and oneness you will feel with all things. It may seem contradictory, but the miraculous creation of your physical body is the temple of spiritual reality, and the organic instrument by which one receives spiritual nourishment, and revelation. The human mind is nourished and healed when it allows thought to "flow" through it as an organic response to physical stimulus. When the will chooses to obsess over thought the spirit descends into darkness, and the Living Earth suffers.
Light is made of physical particles.
It only exists in material space.
Even imagined light (thoughts containing images)
exists in the darkness of the mind where there is no matter,
so there can be no light.